FFmpegWriter.cpp

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// Copyright (c) 2008-2025 OpenShot Studios, LLC, Fabrice Bellard
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include <algorithm>
#include <chrono>
#include <cstdarg>
#include <iostream>
#include <memory>
#include <set>
#include <cmath>
#include <ctime>
#include <sstream>
#include <unistd.h>
 
#include "FFmpegUtilities.h"
 
#include "FFmpegWriter.h"
#include "Exceptions.h"
#include "Frame.h"
#include "OpenMPUtilities.h"
#include "Settings.h"
#include "Logger.h"
 
using namespace openshot;
 
// Multiplexer parameters temporary storage
AVDictionary *mux_dict = NULL;
 
#if USE_HW_ACCEL
int hw_en_on = 1;                   // Is set in UI
int hw_en_supported = 0;    // Is set by FFmpegWriter
AVPixelFormat hw_en_av_pix_fmt = AV_PIX_FMT_NONE;
AVHWDeviceType hw_en_av_device_type = AV_HWDEVICE_TYPE_VAAPI;
static AVBufferRef *hw_device_ctx = NULL;
AVFrame *hw_frame = NULL;
 
static int set_hwframe_ctx(AVCodecContext *ctx, AVBufferRef *hw_device_ctx, int64_t width, int64_t height)
{
    AVBufferRef *hw_frames_ref;
    AVHWFramesContext *frames_ctx = NULL;
    int err = 0;
 
    if (!(hw_frames_ref = av_hwframe_ctx_alloc(hw_device_ctx))) {
        std::clog << "Failed to create HW frame context.\n";
        return -1;
    }
    frames_ctx = (AVHWFramesContext *)(hw_frames_ref->data);
    frames_ctx->format = hw_en_av_pix_fmt;
    frames_ctx->sw_format = AV_PIX_FMT_NV12;
    frames_ctx->width = width;
    frames_ctx->height = height;
    frames_ctx->initial_pool_size = 20;
    if ((err = av_hwframe_ctx_init(hw_frames_ref)) < 0) {
        std::clog << "Failed to initialize HW frame context. " <<
            "Error code: " << av_err2string(err) << "\n";
        av_buffer_unref(&hw_frames_ref);
        return err;
    }
    ctx->hw_frames_ctx = av_buffer_ref(hw_frames_ref);
    if (!ctx->hw_frames_ctx)
        err = AVERROR(ENOMEM);
 
    av_buffer_unref(&hw_frames_ref);
    return err;
}
#endif // USE_HW_ACCEL
 
FFmpegWriter::FFmpegWriter(const std::string& path) :
        path(path), oc(NULL), audio_st(NULL), video_st(NULL), samples(NULL),
        audio_outbuf(NULL), audio_outbuf_size(0), audio_input_frame_size(0), audio_input_position(0),
        initial_audio_input_frame_size(0), img_convert_ctx(NULL),
        video_codec_ctx(NULL), audio_codec_ctx(NULL), is_writing(false), video_timestamp(0), audio_timestamp(0),
        original_sample_rate(0), original_channels(0), avr(NULL), avr_planar(NULL), is_open(false), prepare_streams(false),
        write_header(false), write_trailer(false), allow_b_frames(false), testing(false), audio_encoder_buffer_size(0), audio_encoder_buffer(NULL) {
 
    // Disable audio & video (so they can be independently enabled)
    info.has_audio = false;
    info.has_video = false;
 
    // Initialize FFMpeg, and register all formats and codecs
    AV_REGISTER_ALL
 
    // auto detect format
    auto_detect_format();
}
 
// Open the writer
void FFmpegWriter::Open() {
    if (!is_open) {
        // Open the writer
        is_open = true;
 
        // Prepare streams (if needed)
        if (!prepare_streams)
            PrepareStreams();
 
        // Now that all the parameters are set, we can open the audio and video codecs and allocate the necessary encode buffers
        if (info.has_video && video_st)
            open_video(oc, video_st);
        if (info.has_audio && audio_st)
            open_audio(oc, audio_st);
 
        // Write header (if needed)
        if (!write_header)
            WriteHeader();
    }
}
 
// auto detect format (from path)
void FFmpegWriter::auto_detect_format() {
 
    // Allocate the output media context
    AV_OUTPUT_CONTEXT(&oc, path.c_str());
    if (!oc) {
        throw OutOfMemory(
            "Could not allocate memory for AVFormatContext.", path);
    }
 
    // Determine what format to use when encoding this output filename
    oc->oformat = av_guess_format(NULL, path.c_str(), NULL);
    if (oc->oformat == nullptr) {
        throw InvalidFormat("Could not deduce output format from file extension.", path);
    }
 
    // Update video & audio codec name
    if (oc->oformat->video_codec != AV_CODEC_ID_NONE && info.has_video) {
        const AVCodec *vcodec = avcodec_find_encoder(oc->oformat->video_codec);
        info.vcodec = vcodec ? vcodec->name : std::string();
    }
    if (oc->oformat->audio_codec != AV_CODEC_ID_NONE && info.has_audio) {
        const AVCodec *acodec = avcodec_find_encoder(oc->oformat->audio_codec);
        info.acodec = acodec ? acodec->name : std::string();
    }
}
 
// initialize streams
void FFmpegWriter::initialize_streams() {
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::initialize_streams",
        "oc->oformat->video_codec", oc->oformat->video_codec,
        "oc->oformat->audio_codec", oc->oformat->audio_codec,
        "AV_CODEC_ID_NONE", AV_CODEC_ID_NONE);
 
    // Add the audio and video streams using the default format codecs and initialize the codecs
    video_st = NULL;
    audio_st = NULL;
    if (oc->oformat->video_codec != AV_CODEC_ID_NONE && info.has_video)
        // Add video stream
        video_st = add_video_stream();
 
    if (oc->oformat->audio_codec != AV_CODEC_ID_NONE && info.has_audio)
        // Add audio stream
        audio_st = add_audio_stream();
}
 
// Set video export options
void FFmpegWriter::SetVideoOptions(bool has_video, std::string codec, Fraction fps, int width, int height, Fraction pixel_ratio, bool interlaced, bool top_field_first, int bit_rate) {
    // Set the video options
    if (codec.length() > 0) {
        const AVCodec *new_codec;
        // Check if the codec selected is a hardware accelerated codec
#if USE_HW_ACCEL
#if defined(__linux__)
        if (strstr(codec.c_str(), "_vaapi") != NULL) {
            new_codec = avcodec_find_encoder_by_name(codec.c_str());
            hw_en_on = 1;
            hw_en_supported = 1;
            hw_en_av_pix_fmt = AV_PIX_FMT_VAAPI;
            hw_en_av_device_type = AV_HWDEVICE_TYPE_VAAPI;
        } else if (strstr(codec.c_str(), "_nvenc") != NULL) {
            new_codec = avcodec_find_encoder_by_name(codec.c_str());
            hw_en_on = 1;
            hw_en_supported = 1;
            hw_en_av_pix_fmt = AV_PIX_FMT_CUDA;
            hw_en_av_device_type = AV_HWDEVICE_TYPE_CUDA;
        } else {
            new_codec = avcodec_find_encoder_by_name(codec.c_str());
            hw_en_on = 0;
            hw_en_supported = 0;
        }
#elif defined(_WIN32)
        if (strstr(codec.c_str(), "_dxva2") != NULL) {
            new_codec = avcodec_find_encoder_by_name(codec.c_str());
            hw_en_on = 1;
            hw_en_supported = 1;
            hw_en_av_pix_fmt = AV_PIX_FMT_DXVA2_VLD;
            hw_en_av_device_type = AV_HWDEVICE_TYPE_DXVA2;
        } else if (strstr(codec.c_str(), "_nvenc") != NULL) {
            new_codec = avcodec_find_encoder_by_name(codec.c_str());
            hw_en_on = 1;
            hw_en_supported = 1;
            hw_en_av_pix_fmt = AV_PIX_FMT_CUDA;
            hw_en_av_device_type = AV_HWDEVICE_TYPE_CUDA;
        } else {
            new_codec = avcodec_find_encoder_by_name(codec.c_str());
            hw_en_on = 0;
            hw_en_supported = 0;
        }
#elif defined(__APPLE__)
        if (strstr(codec.c_str(), "_videotoolbox") != NULL) {
            new_codec = avcodec_find_encoder_by_name(codec.c_str());
            hw_en_on = 1;
            hw_en_supported = 1;
            hw_en_av_pix_fmt = AV_PIX_FMT_VIDEOTOOLBOX;
            hw_en_av_device_type = AV_HWDEVICE_TYPE_VIDEOTOOLBOX;
        } else {
            new_codec = avcodec_find_encoder_by_name(codec.c_str());
            hw_en_on = 0;
            hw_en_supported = 0;
        }
#else  // unknown OS
        new_codec = avcodec_find_encoder_by_name(codec.c_str());
#endif //__linux__/_WIN32/__APPLE__
#else // USE_HW_ACCEL
        new_codec = avcodec_find_encoder_by_name(codec.c_str());
#endif // USE_HW_ACCEL
        if (new_codec == NULL)
            throw InvalidCodec("A valid video codec could not be found for this file.", path);
        else {
            // Set video codec
            info.vcodec = new_codec->name;
        }
    }
    if (fps.num > 0) {
        // Set frames per second (if provided)
        info.fps.num = fps.num;
        info.fps.den = fps.den;
 
        // Set the timebase (inverse of fps)
        info.video_timebase.num = info.fps.den;
        info.video_timebase.den = info.fps.num;
    }
    if (width >= 1)
        info.width = width;
    if (height >= 1)
        info.height = height;
    if (pixel_ratio.num > 0) {
        info.pixel_ratio.num = pixel_ratio.num;
        info.pixel_ratio.den = pixel_ratio.den;
    }
    if (bit_rate >= 1000)  // bit_rate is the bitrate in b/s
        info.video_bit_rate = bit_rate;
    if ((bit_rate >= 0) && (bit_rate < 256))  // bit_rate is the bitrate in crf
        info.video_bit_rate = bit_rate;
 
    info.interlaced_frame = interlaced;
    info.top_field_first = top_field_first;
 
    // Calculate the DAR (display aspect ratio)
    Fraction size(info.width * info.pixel_ratio.num, info.height * info.pixel_ratio.den);
 
    // Reduce size fraction
    size.Reduce();
 
    // Set the ratio based on the reduced fraction
    info.display_ratio.num = size.num;
    info.display_ratio.den = size.den;
 
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::SetVideoOptions (" + codec + ")",
        "width", width, "height", height,
        "size.num", size.num, "size.den", size.den,
        "fps.num", fps.num, "fps.den", fps.den);
 
    // Enable / Disable video
    info.has_video = has_video;
}
 
// Set video export options (overloaded function)
void FFmpegWriter::SetVideoOptions(std::string codec, int width, int height,  Fraction fps, int bit_rate) {
    // Call full signature with some default parameters
    FFmpegWriter::SetVideoOptions(
        true, codec, fps, width, height,
        openshot::Fraction(1, 1), false, true, bit_rate
    );
}
 
 
// Set audio export options
void FFmpegWriter::SetAudioOptions(bool has_audio, std::string codec, int sample_rate, int channels, ChannelLayout channel_layout, int bit_rate) {
    // Set audio options
    if (codec.length() > 0) {
        const AVCodec *new_codec = avcodec_find_encoder_by_name(codec.c_str());
        if (new_codec == NULL)
            throw InvalidCodec("A valid audio codec could not be found for this file.", path);
        else {
            // Set audio codec
            info.acodec = new_codec->name;
        }
    }
    if (sample_rate > 7999)
        info.sample_rate = sample_rate;
    if (channels > 0)
        info.channels = channels;
    if (bit_rate > 999)
        info.audio_bit_rate = bit_rate;
    info.channel_layout = channel_layout;
 
    // init resample options (if zero)
    if (original_sample_rate == 0)
        original_sample_rate = info.sample_rate;
    if (original_channels == 0)
        original_channels = info.channels;
 
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::SetAudioOptions (" + codec + ")",
        "sample_rate", sample_rate,
        "channels", channels,
        "bit_rate", bit_rate);
 
    // Enable / Disable audio
    info.has_audio = has_audio;
}
 
 
// Set audio export options (overloaded function)
void FFmpegWriter::SetAudioOptions(std::string codec, int sample_rate, int bit_rate) {
    // Call full signature with some default parameters
    FFmpegWriter::SetAudioOptions(
        true, codec, sample_rate, 2,
        openshot::LAYOUT_STEREO, bit_rate
    );
}
 
 
// Set custom options (some codecs accept additional params)
void FFmpegWriter::SetOption(StreamType stream, std::string name, std::string value) {
    // Declare codec context
    AVCodecContext *c = NULL;
    AVStream *st = NULL;
    std::stringstream convert(value);
 
    if (info.has_video && stream == VIDEO_STREAM && video_st) {
        st = video_st;
        // Get codec context
        c = AV_GET_CODEC_PAR_CONTEXT(st, video_codec_ctx);
        // Was a codec / stream found?
        if (c) {
            if (info.interlaced_frame) {
                c->field_order = info.top_field_first ? AV_FIELD_TT : AV_FIELD_BB;
                // We only use these two version and ignore AV_FIELD_TB and AV_FIELD_BT
                // Otherwise we would need to change the whole export window
            }
        }
    } else if (info.has_audio && stream == AUDIO_STREAM && audio_st) {
        st = audio_st;
        // Get codec context
        c = AV_GET_CODEC_PAR_CONTEXT(st, audio_codec_ctx);
    } else
        throw NoStreamsFound("The stream was not found. Be sure to call PrepareStreams() first.", path);
 
    // Init AVOption
    const AVOption *option = NULL;
 
    // Was a codec / stream found?
    if (c)
        // Find AVOption (if it exists)
        option = AV_OPTION_FIND(c->priv_data, name.c_str());
 
    // Was option found?
    if (option || (name == "g" || name == "qmin" || name == "qmax" || name == "max_b_frames" || name == "mb_decision" ||
                   name == "level" || name == "profile" || name == "slices" || name == "rc_min_rate" || name == "rc_max_rate" ||
                   name == "rc_buffer_size" || name == "crf" || name == "cqp" || name == "qp" || name == "allow_b_frames")) {
        // Check for specific named options
        if (name == "g")
            // Set gop_size
            convert >> c->gop_size;
 
        else if (name == "qmin")
            // Minimum quantizer
            convert >> c->qmin;
 
        else if (name == "qmax")
            // Maximum quantizer
            convert >> c->qmax;
 
        else if (name == "max_b_frames")
            // Maximum number of B-frames between non-B-frames
            convert >> c->max_b_frames;
 
        else if (name == "allow_b_frames")
            // Preserve configured B-frames for codecs that support them.
            // Values: 1/true/yes/on to enable, everything else disables.
            allow_b_frames = (value == "1" || value == "true" || value == "yes" || value == "on");
 
        else if (name == "mb_decision")
            // Macroblock decision mode
            convert >> c->mb_decision;
 
        else if (name == "level")
            // Set codec level
            convert >> c->level;
 
        else if (name == "profile")
            // Set codec profile
            convert >> c->profile;
 
        else if (name == "slices")
            // Indicates number of picture subdivisions
            convert >> c->slices;
 
        else if (name == "rc_min_rate")
            // Minimum bitrate
            convert >> c->rc_min_rate;
 
        else if (name == "rc_max_rate")
            // Maximum bitrate
            convert >> c->rc_max_rate;
 
        else if (name == "rc_buffer_size")
            // Buffer size
            convert >> c->rc_buffer_size;
 
        else if (name == "cqp") {
            // encode quality and special settings like lossless
#if USE_HW_ACCEL
            if (hw_en_on) {
                av_opt_set_int(c->priv_data, "qp", std::min(std::stoi(value),63), 0); // 0-63
            } else
#endif // USE_HW_ACCEL
            {
                switch (c->codec_id) {
#if (LIBAVCODEC_VERSION_MAJOR >= 58)
                // FFmpeg 4.0+
                case AV_CODEC_ID_AV1 :
                    c->bit_rate = 0;
                    av_opt_set_int(c->priv_data, "qp", std::min(std::stoi(value),63), 0); // 0-63
                    break;
#endif
                case AV_CODEC_ID_VP8 :
                    c->bit_rate = 10000000;
                    av_opt_set_int(c->priv_data, "qp", std::max(std::min(std::stoi(value), 63), 4), 0); // 4-63
                    break;
                case AV_CODEC_ID_VP9 :
                    c->bit_rate = 0;  // Must be zero!
                    av_opt_set_int(c->priv_data, "qp", std::min(std::stoi(value), 63), 0); // 0-63
                    if (std::stoi(value) == 0) {
                        av_opt_set(c->priv_data, "preset", "veryslow", 0);
                        av_opt_set_int(c->priv_data, "lossless", 1, 0);
                    }
                    break;
                case AV_CODEC_ID_H264 :
                    av_opt_set_int(c->priv_data, "qp", std::min(std::stoi(value), 51), 0); // 0-51
                    if (std::stoi(value) == 0) {
                        av_opt_set(c->priv_data, "preset", "veryslow", 0);
                            c->pix_fmt = PIX_FMT_YUV444P; // no chroma subsampling
                    }
                    break;
                case AV_CODEC_ID_HEVC :
                    av_opt_set_int(c->priv_data, "qp", std::min(std::stoi(value), 51), 0); // 0-51
                    if (std::stoi(value) == 0) {
                        av_opt_set(c->priv_data, "preset", "veryslow", 0);
                        av_opt_set_int(c->priv_data, "lossless", 1, 0);
                    }
                    break;
                default:
                    // For all other codecs assume a range of 0-63
                    av_opt_set_int(c->priv_data, "qp", std::min(std::stoi(value), 63), 0); // 0-63
                    c->bit_rate = 0;
                }
            }
        } else if (name == "crf") {
            // encode quality and special settings like lossless
#if USE_HW_ACCEL
            if (hw_en_on) {
                double mbs = 15000000.0;
                if (info.video_bit_rate > 0) {
                    if (info.video_bit_rate > 42) {
                        mbs = 380000.0;
                    }
                    else {
                        mbs *= std::pow(0.912,info.video_bit_rate);
                    }
                }
                c->bit_rate = (int)(mbs);
            } else
#endif // USE_HW_ACCEL
            {
                switch (c->codec_id) {
#if (LIBAVCODEC_VERSION_MAJOR >= 58)
                // FFmpeg 4.0+
                    case AV_CODEC_ID_AV1 :
                        c->bit_rate = 0;
                        // AV1 only supports "crf" quality values
                        av_opt_set_int(c->priv_data, "crf", std::min(std::stoi(value),63), 0);
                        break;
#endif
                    case AV_CODEC_ID_VP8 :
                        c->bit_rate = 10000000;
                        av_opt_set_int(c->priv_data, "crf", std::max(std::min(std::stoi(value), 63), 4), 0); // 4-63
                        break;
                    case AV_CODEC_ID_VP9 :
                        c->bit_rate = 0;  // Must be zero!
                        av_opt_set_int(c->priv_data, "crf", std::min(std::stoi(value), 63), 0); // 0-63
                        if (std::stoi(value) == 0) {
                            av_opt_set(c->priv_data, "preset", "veryslow", 0);
                            av_opt_set_int(c->priv_data, "lossless", 1, 0);
                        }
                        break;
                    case AV_CODEC_ID_H264 :
                        av_opt_set_int(c->priv_data, "crf", std::min(std::stoi(value), 51), 0); // 0-51
                        if (std::stoi(value) == 0) {
                            av_opt_set(c->priv_data, "preset", "veryslow", 0);
                            c->pix_fmt = PIX_FMT_YUV444P; // no chroma subsampling
                        }
                        break;
                    case AV_CODEC_ID_HEVC :
                        if (strstr(info.vcodec.c_str(), "svt_hevc") != NULL) {
                            av_opt_set_int(c->priv_data, "preset", 7, 0);
                            av_opt_set_int(c->priv_data, "forced-idr",1,0);
                            av_opt_set_int(c->priv_data, "qp",std::min(std::stoi(value), 51),0);
                        }
                        else {
                            av_opt_set_int(c->priv_data, "crf", std::min(std::stoi(value), 51), 0); // 0-51
                        }
                        if (std::stoi(value) == 0) {
                            av_opt_set(c->priv_data, "preset", "veryslow", 0);
                            av_opt_set_int(c->priv_data, "lossless", 1, 0);
                        }
                        break;
                    default:
                        // If this codec doesn't support crf calculate a bitrate
                        // TODO: find better formula
                        double mbs = 15000000.0;
                        if (info.video_bit_rate > 0) {
                            if (info.video_bit_rate > 42) {
                                mbs = 380000.0;
                            } else {
                                mbs *= std::pow(0.912, info.video_bit_rate);
                            }
                        }
                        c->bit_rate = (int) (mbs);
                }
            }
        } else if (name == "qp") {
            // encode quality and special settings like lossless
#if (LIBAVCODEC_VERSION_MAJOR >= 58)
    // FFmpeg 4.0+
                switch (c->codec_id) {
                    case AV_CODEC_ID_AV1 :
                        c->bit_rate = 0;
                        if (strstr(info.vcodec.c_str(), "svtav1") != NULL) {
                            av_opt_set_int(c->priv_data, "qp", std::min(std::stoi(value),63), 0);
                        }
                        else if (strstr(info.vcodec.c_str(), "rav1e") != NULL) {
                            // Set number of tiles to a fixed value
                            // TODO Let user choose number of tiles
                            av_opt_set_int(c->priv_data, "qp", std::min(std::stoi(value),255), 0);
                        }
                        else if (strstr(info.vcodec.c_str(), "aom") != NULL) {
                            // Set number of tiles to a fixed value
                            // TODO Let user choose number of tiles
                            // libaom doesn't have qp only crf
                            av_opt_set_int(c->priv_data, "crf", std::min(std::stoi(value),63), 0);
                        }
                        else {
                            av_opt_set_int(c->priv_data, "crf", std::min(std::stoi(value),63), 0);
                        }
                    case AV_CODEC_ID_HEVC :
                        c->bit_rate = 0;
                        if (strstr(info.vcodec.c_str(), "svt_hevc") != NULL) {
                            av_opt_set_int(c->priv_data, "qp", std::min(std::stoi(value),51), 0);
                            av_opt_set_int(c->priv_data, "preset", 7, 0);
                            av_opt_set_int(c->priv_data, "forced-idr",1,0);
                        }
                        break;
                }
#endif  // FFmpeg 4.0+
        } else {
            // Set AVOption
            AV_OPTION_SET(st, c->priv_data, name.c_str(), value.c_str(), c);
        }
 
        Logger::Instance()->AppendDebugMethod(
            "FFmpegWriter::SetOption (" + (std::string)name + ")",
            "stream == VIDEO_STREAM", stream == VIDEO_STREAM);
 
    // Muxing dictionary is not part of the codec context.
    // Just reusing SetOption function to set popular multiplexing presets.
    } else if (name == "muxing_preset") {
        if (value == "mp4_faststart") {
            // 'moov' box to the beginning; only for MOV, MP4
            av_dict_set(&mux_dict, "movflags", "faststart", 0);
        } else if (value == "mp4_fragmented") {
            // write selfcontained fragmented file, minimum length of the fragment 8 sec; only for MOV, MP4
            av_dict_set(&mux_dict, "movflags", "frag_keyframe", 0);
            av_dict_set(&mux_dict, "min_frag_duration", "8000000", 0);
        }
    } else {
        throw InvalidOptions("The option is not valid for this codec.", path);
    }
 
}
 
bool FFmpegWriter::IsValidCodec(std::string codec_name) {
    // Initialize FFMpeg, and register all formats and codecs
    AV_REGISTER_ALL
 
    // Find the codec (if any)
    return avcodec_find_encoder_by_name(codec_name.c_str()) != NULL;
}
 
// Find an output format the same way the writer does (by extension), or by short name
static const AVOutputFormat* find_output_format(std::string format_name) {
    if (!format_name.empty() && format_name[0] == '.')
        format_name.erase(0, 1);
    if (format_name.empty())
        return nullptr;
    const AVOutputFormat* format = av_guess_format(NULL, ("file." + format_name).c_str(), NULL);
    if (!format)
        format = av_guess_format(format_name.c_str(), NULL, NULL);
    return format;
}
 
// Visit every registered encoder
template<typename Visitor>
static void for_each_encoder(Visitor visit) {
#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(58, 10, 100)
    void* iterator = nullptr;
    const AVCodec* codec = nullptr;
    while ((codec = av_codec_iterate(&iterator)))
#else
    const AVCodec* codec = nullptr;
    while ((codec = av_codec_next(codec)))
#endif
        if (av_codec_is_encoder(codec))
            visit(codec);
}
 
// Visit every registered output format (muxer)
template<typename Visitor>
static void for_each_muxer(Visitor visit) {
#if LIBAVFORMAT_VERSION_INT >= AV_VERSION_INT(58, 9, 100)
    void* iterator = nullptr;
    const AVOutputFormat* format = nullptr;
    while ((format = av_muxer_iterate(&iterator)))
#else
    AVOutputFormat* format = nullptr;
    while ((format = av_oformat_next(format)))
#endif
        visit(format);
}
 
// Name of the encoder FFmpeg would pick for a codec ID (or an empty string)
static std::string default_encoder_name(AVCodecID codec_id) {
    if (codec_id == AV_CODEC_ID_NONE)
        return "";
    const AVCodec* codec = avcodec_find_encoder(codec_id);
    return codec ? codec->name : "";
}
 
// Codecs FFmpeg uses for single image files (i.e. png, bmp, tiff), from its image2 format
static const std::set<AVCodecID>& image_codec_ids() {
    static const std::set<AVCodecID> ids = [] {
        std::set<AVCodecID> found;
        const AVOutputFormat* image2 = av_guess_format("image2", NULL, NULL);
        if (!image2 || !image2->extensions)
            return found;
        std::stringstream extension_list(image2->extensions);
        std::string extension;
        while (std::getline(extension_list, extension, ',')) {
            AVCodecID id = av_guess_codec(const_cast<AVOutputFormat*>(image2), NULL,
                                          ("file." + extension).c_str(), NULL, AVMEDIA_TYPE_VIDEO);
            if (id != AV_CODEC_ID_NONE)
                found.insert(id);
        }
        return found;
    }();
    return ids;
}
 
static bool encoder_has_option(const AVCodec* codec, const char* name) {
    if (!codec->priv_class)
        return false;
    const AVClass* priv_class = codec->priv_class;
    return av_opt_find(&priv_class, name, NULL, 0, AV_OPT_SEARCH_FAKE_OBJ) != nullptr;
}
 
std::string FFmpegWriter::GetEncoderInfo(std::string codec_name) {
    AV_REGISTER_ALL
 
    Json::Value root;
    const AVCodec* codec = avcodec_find_encoder_by_name(codec_name.c_str());
    root["found"] = codec != nullptr;
    if (!codec)
        return root.toStyledString();
 
    root["name"] = codec->name;
    root["long_name"] = codec->long_name ? codec->long_name : "";
    const char* media_type = av_get_media_type_string(codec->type);
    root["type"] = media_type ? media_type : "unknown";
 
    bool hardware = false;
#ifdef AV_CODEC_CAP_HARDWARE
    hardware = hardware || (codec->capabilities & AV_CODEC_CAP_HARDWARE);
#endif
#ifdef AV_CODEC_CAP_HYBRID
    hardware = hardware || (codec->capabilities & AV_CODEC_CAP_HYBRID);
#endif
    root["hardware"] = hardware;
#ifdef AV_CODEC_CAP_EXPERIMENTAL
    root["experimental"] = (codec->capabilities & AV_CODEC_CAP_EXPERIMENTAL) != 0;
#else
    root["experimental"] = (codec->capabilities & CODEC_CAP_EXPERIMENTAL) != 0;
#endif
 
    // Lossless-only codecs (FLAC, PCM, FFV1) ignore the bit rate
    const AVCodecDescriptor* descriptor = avcodec_descriptor_get(codec->id);
    root["lossless"] = descriptor && (descriptor->props & AV_CODEC_PROP_LOSSLESS);
    root["lossy"] = descriptor && (descriptor->props & AV_CODEC_PROP_LOSSY);
    // Every frame is a picture (i.e. ProRes, DNxHD, MJPEG), which suits editing over delivery
    root["intra_only"] = descriptor && (descriptor->props & AV_CODEC_PROP_INTRA_ONLY);
    // Writes single image files (i.e. png, bmp, tiff)
    root["image"] = image_codec_ids().count(codec->id) > 0;
    // The codec this encoder writes (i.e. "h264" for libx264 and h264_nvenc)
    root["codec"] = avcodec_get_name(codec->id);
 
    Json::Value quality_options(Json::arrayValue);
    for (const char* option : {"crf", "qp", "cq", "global_quality"})
        if (encoder_has_option(codec, option))
            quality_options.append(option);
    root["quality_options"] = quality_options;
 
    root["sample_rates"] = Json::Value(Json::nullValue);
    root["channel_layouts"] = Json::Value(Json::nullValue);
    root["sample_formats"] = Json::Value(Json::nullValue);
    root["pixel_formats"] = Json::Value(Json::nullValue);
 
    std::unique_ptr<AVCodecContext, void(*)(AVCodecContext*)> context(
        avcodec_alloc_context3(codec),
        [](AVCodecContext* value) { avcodec_free_context(&value); });
    if (!context)
        return root.toStyledString();
 
    try {
        if (codec->type == AVMEDIA_TYPE_AUDIO) {
            if (const int* rates = ffmpeg_codec_sample_rates(codec, context.get())) {
                Json::Value values(Json::arrayValue);
                for (int i = 0; rates[i] != 0; i++)
                    values.append(rates[i]);
                root["sample_rates"] = values;
            }
#if HAVE_CH_LAYOUT
            if (const AVChannelLayout* layouts = ffmpeg_codec_ch_layouts(codec, context.get())) {
                Json::Value values(Json::arrayValue);
                for (int i = 0; av_channel_layout_check(&layouts[i]); i++)
                    if (layouts[i].order == AV_CHANNEL_ORDER_NATIVE)
                        values.append((Json::UInt64) layouts[i].u.mask);
                root["channel_layouts"] = values;
            }
#else
            if (codec->channel_layouts) {
                Json::Value values(Json::arrayValue);
                for (int i = 0; codec->channel_layouts[i] != 0; i++)
                    values.append((Json::UInt64) codec->channel_layouts[i]);
                root["channel_layouts"] = values;
            }
#endif
            if (const AVSampleFormat* formats = ffmpeg_codec_sample_fmts(codec, context.get())) {
                Json::Value values(Json::arrayValue);
                for (int i = 0; formats[i] != AV_SAMPLE_FMT_NONE; i++) {
                    const char* name = av_get_sample_fmt_name(formats[i]);
                    if (name)
                        values.append(name);
                }
                root["sample_formats"] = values;
            }
        } else if (codec->type == AVMEDIA_TYPE_VIDEO) {
            if (const AVPixelFormat* formats = ffmpeg_codec_pix_fmts(codec, context.get())) {
                Json::Value values(Json::arrayValue);
                for (int i = 0; formats[i] != AV_PIX_FMT_NONE; i++) {
                    const char* name = av_get_pix_fmt_name(formats[i]);
                    if (name)
                        values.append(name);
                }
                root["pixel_formats"] = values;
            }
        }
    } catch (const InvalidCodec&) {
        // Leave the remaining lists unrestricted; the writer reports real failures on open
    }
 
    return root.toStyledString();
}
 
std::string FFmpegWriter::GetFormatInfo(std::string format_name) {
    AV_REGISTER_ALL
 
    Json::Value root;
    const AVOutputFormat* format = find_output_format(format_name);
    root["found"] = format != nullptr;
    if (!format)
        return root.toStyledString();
 
    root["name"] = format->name;
    root["long_name"] = format->long_name ? format->long_name : "";
    Json::Value extensions(Json::arrayValue);
    std::stringstream extension_list(format->extensions ? format->extensions : "");
    std::string extension;
    while (std::getline(extension_list, extension, ','))
        if (!extension.empty())
            extensions.append(extension);
    root["extensions"] = extensions;
    root["default_audio_codec"] = default_encoder_name(format->audio_codec);
    root["default_video_codec"] = default_encoder_name(format->video_codec);
    return root.toStyledString();
}
 
std::string FFmpegWriter::GetFormats() {
    AV_REGISTER_ALL
 
    Json::Value formats(Json::arrayValue);
    std::set<std::string> listed;
    for_each_muxer([&](const AVOutputFormat* format) {
        std::stringstream extension_list(format->extensions ? format->extensions : "");
        std::string extension;
        while (std::getline(extension_list, extension, ',')) {
            // Some formats list extensions with stray spaces (i.e. " A64")
            extension.erase(0, extension.find_first_not_of(" \t"));
            extension.erase(extension.find_last_not_of(" \t") + 1);
            // Extensions match without case, so list each once, in lower case
            std::transform(extension.begin(), extension.end(), extension.begin(), ::tolower);
            if (extension.empty() || listed.count(extension))
                continue;
            // The writer picks its format from the file extension, so only list extensions
            // that pick this format (several formats can claim the same extension)
            if (av_guess_format(NULL, ("file." + extension).c_str(), NULL) != format)
                continue;
            listed.insert(extension);
            Json::Value row;
            row["extension"] = extension;
            row["name"] = format->name;
            row["long_name"] = format->long_name ? format->long_name : "";
            row["default_audio_codec"] = default_encoder_name(format->audio_codec);
            row["default_video_codec"] = default_encoder_name(format->video_codec);
            formats.append(row);
        }
    });
    return formats.toStyledString();
}
 
std::string FFmpegWriter::GetEncoders(std::string media_type, std::string format_name) {
    AV_REGISTER_ALL
 
    Json::Value encoders(Json::arrayValue);
    const AVOutputFormat* format = nullptr;
    if (!format_name.empty()) {
        format = find_output_format(format_name);
        if (!format)
            return encoders.toStyledString();
    }
 
    for_each_encoder([&](const AVCodec* codec) {
        const char* type = av_get_media_type_string(codec->type);
        if (!type || media_type != type)
            return;
        // Keep encoders FFmpeg can't rule out; the writer reports real failures on open
        if (format && avformat_query_codec(format, codec->id, FF_COMPLIANCE_NORMAL) == 0)
            return;
        Json::Value encoder;
        encoder["name"] = codec->name;
        encoder["long_name"] = codec->long_name ? codec->long_name : "";
        encoders.append(encoder);
    });
    return encoders.toStyledString();
}
 
int FFmpegWriter::IsCodecSupportedByFormat(std::string format_name, std::string codec_name) {
    AV_REGISTER_ALL
 
    const AVOutputFormat* format = find_output_format(format_name);
    const AVCodec* codec = avcodec_find_encoder_by_name(codec_name.c_str());
    if (!format || !codec)
        return 0;
    const int result = avformat_query_codec(format, codec->id, FF_COMPLIANCE_NORMAL);
    if (result < 0)
        return -1;
    return result > 0 ? 1 : 0;
}
 
// FFmpeg messages logged on a thread running Test() (other threads print as usual)
struct TestLogLine {
    int level;
    std::string text;
};
static thread_local std::vector<TestLogLine>* test_log = nullptr;
 
static void test_log_callback(void* avcl, int level, const char* fmt, va_list vl) {
    if (!test_log) {
        av_log_default_callback(avcl, level, fmt, vl);
        return;
    }
    if (level > AV_LOG_WARNING)
        return;
    char line[1024];
    vsnprintf(line, sizeof(line), fmt, vl);
    std::string text(line);
    while (!text.empty() && (text.back() == '\n' || text.back() == '\r' || text.back() == ' '))
        text.pop_back();
    if (text.empty())
        return;
    // Name the component (i.e. "mp3: ...") instead of FFmpeg's "[mp3 @ 0x...]" prefix
    AVClass* av_class = avcl ? *(AVClass**)avcl : nullptr;
    if (av_class && av_class->item_name)
        text = std::string(av_class->item_name(avcl)) + ": " + text;
    test_log->push_back({level, text});
}
 
// Check the current settings without writing a file
std::string FFmpegWriter::Test() {
    auto start = std::chrono::steady_clock::now();
    std::vector<TestLogLine> messages;
    std::string stage;
    std::string error;
 
    testing = true;
    test_log = &messages;
    av_log_set_callback(test_log_callback);
 
    try {
        if (!prepare_streams)
            PrepareStreams();
        if (info.has_video && video_st) {
            stage = "video";
            open_video(oc, video_st);
        }
        if (info.has_audio && audio_st) {
            stage = "audio";
            open_audio(oc, audio_st);
        }
        stage = "header";
        WriteHeader();
        av_write_trailer(oc);
        write_trailer = true;
        stage = "";
    } catch (const ExceptionBase& e) {
        error = e.what();
    } catch (const std::exception& e) {
        error = e.what();
    }
 
    // Release everything (the test output, encoders, and any hardware device)
    if (oc && oc->pb && !(oc->oformat->flags & AVFMT_NOFILE)) {
        uint8_t* buffer = NULL;
        avio_close_dyn_buf(oc->pb, &buffer);
        av_free(buffer);
        oc->pb = NULL;
    }
    if (video_st)
        close_video(oc, video_st);
    if (audio_st)
        close_audio(oc, audio_st);
    video_codec_ctx = NULL;
    audio_codec_ctx = NULL;
    video_st = NULL;
    audio_st = NULL;
    if (oc) {
        avformat_free_context(oc);
        oc = NULL;
    }
    if (mux_dict)
        av_dict_free(&mux_dict);
    av_log_set_callback(av_log_default_callback);
    test_log = nullptr;
    is_open = false;
    prepare_streams = false;
    write_header = false;
    write_trailer = false;
    testing = false;
 
    // FFmpeg's own explanation (its last error) is clearer than the exception text
    std::string message = error;
    if (!error.empty()) {
        for (auto line = messages.rbegin(); line != messages.rend(); ++line) {
            if (line->level <= AV_LOG_ERROR) {
                message = line->text;
                break;
            }
        }
    }
 
    Json::Value root;
    root["ok"] = error.empty();
    root["stage"] = stage;
    root["message"] = message;
    root["log"] = Json::Value(Json::arrayValue);
    for (const auto& line : messages)
        root["log"].append(line.text);
    root["elapsed_ms"] = (Json::Int64) std::chrono::duration_cast<std::chrono::milliseconds>(
        std::chrono::steady_clock::now() - start).count();
    return root.toStyledString();
}
 
// Prepare & initialize streams and open codecs
void FFmpegWriter::PrepareStreams() {
    if (!info.has_audio && !info.has_video)
        throw InvalidOptions("No video or audio options have been set.  You must set has_video or has_audio (or both).", path);
 
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::PrepareStreams [" + path + "]",
        "info.has_audio", info.has_audio,
        "info.has_video", info.has_video);
 
    // Initialize the streams (i.e. add the streams)
    initialize_streams();
 
    // Mark as 'prepared'
    prepare_streams = true;
}
 
// Write the file header (after the options are set)
void FFmpegWriter::WriteHeader() {
    if (!info.has_audio && !info.has_video)
        throw InvalidOptions("No video or audio options have been set.  You must set has_video or has_audio (or both).", path);
 
    // Open the output file, if needed
    if (!(oc->oformat->flags & AVFMT_NOFILE)) {
        if (testing) {
            // Test() writes the header to memory instead
            if (avio_open_dyn_buf(&oc->pb) < 0)
                throw OutOfMemory("Could not allocate memory for the test output.", path);
        } else if (avio_open(&oc->pb, path.c_str(), AVIO_FLAG_WRITE) < 0)
            throw InvalidFile("Could not open or write file.", path);
    }
 
    // Force the output filename (which doesn't always happen for some reason)
    AV_SET_FILENAME(oc, path.c_str());
 
    // Add general metadata (if any)
    for (auto iter = info.metadata.begin(); iter != info.metadata.end(); ++iter) {
        av_dict_set(&oc->metadata, iter->first.c_str(), iter->second.c_str(), 0);
    }
 
    // Set multiplexing parameters (only for MP4/MOV containers)
    AVDictionary *dict = NULL;
    if (mux_dict) {
        av_dict_copy(&dict, mux_dict, 0);
    }
 
    // Write the stream header
    if (avformat_write_header(oc, &dict) != 0) {
        Logger::Instance()->AppendDebugMethod(
            "FFmpegWriter::WriteHeader (avformat_write_header)");
        throw InvalidFile("Could not write header to file.", path);
    };
 
    // Free multiplexing dictionaries sets
    if (dict) av_dict_free(&dict);
    if (mux_dict) av_dict_free(&mux_dict);
 
    // Mark as 'written'
    write_header = true;
 
    Logger::Instance()->AppendDebugMethod("FFmpegWriter::WriteHeader");
}
 
// Add a frame to the queue waiting to be encoded.
void FFmpegWriter::WriteFrame(std::shared_ptr<openshot::Frame> frame) {
    // Check for open reader (or throw exception)
    if (!is_open)
        throw WriterClosed("The FFmpegWriter is closed.  Call Open() before calling this method.", path);
 
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::WriteFrame",
        "frame->number", frame->number,
        "is_writing", is_writing);
 
    // Write frames to video file
    write_frame(frame);
 
    // Keep track of the last frame added
    last_frame = frame;
}
 
void FFmpegWriter::WriteFrameAt(std::shared_ptr<openshot::Frame> frame, int64_t frame_number) {
    // Check for open reader (or throw exception)
    if (!is_open)
        throw WriterClosed("The FFmpegWriter is closed.  Call Open() before calling this method.", path);
 
    if (frame_number < 1) {
        frame_number = 1;
    }
 
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::WriteFrameAt",
        "frame->number", frame->number,
        "output_frame_number", frame_number,
        "is_writing", is_writing);
 
    const int64_t previous_video_timestamp = video_timestamp;
    if (info.has_video && video_st && video_codec_ctx) {
        video_timestamp = av_rescale_q(
            frame_number - 1,
            av_make_q(info.fps.den, info.fps.num),
            video_codec_ctx->time_base);
    }
 
    write_frame(frame);
 
    if (!(info.has_video && video_st && video_codec_ctx)) {
        video_timestamp = previous_video_timestamp;
    }
 
    last_frame = frame;
}
 
// Write all frames in the queue to the video file.
void FFmpegWriter::write_frame(std::shared_ptr<Frame> frame) {
    // Flip writing flag
    is_writing = true;
 
    // Create blank exception
    bool has_error_encoding_video = false;
 
    // Process audio frame
    if (info.has_audio && audio_st)
        write_audio_packets(false, frame);
 
    // Process video frame
    if (info.has_video && video_st)
        process_video_packet(frame);
 
    if (info.has_video && video_st) {
        // Does this frame's AVFrame still exist
        if (av_frames.count(frame)) {
            // Get AVFrame
            AVFrame *frame_final = av_frames[frame];
 
            // Write frame to video file
            if (!write_video_packet(frame, frame_final)) {
                has_error_encoding_video = true;
            }
 
            // Deallocate buffer and AVFrame
            av_freep(&(frame_final->data[0]));
            AV_FREE_FRAME(&frame_final);
            av_frames.erase(frame);
        }
    }
 
    // Done writing
    is_writing = false;
 
    // Raise exception from main thread
    if (has_error_encoding_video)
        throw ErrorEncodingVideo("Error while writing raw video frame", -1);
}
 
// Write a block of frames from a reader
void FFmpegWriter::WriteFrame(ReaderBase *reader, int64_t start, int64_t length) {
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::WriteFrame (from Reader)",
        "start", start,
        "length", length);
 
    // Loop through each frame (and encoded it)
    for (int64_t number = start; number <= length; number++) {
        // Get the frame
        std::shared_ptr<Frame> f = reader->GetFrame(number);
 
        // Encode frame
        WriteFrame(f);
    }
}
 
// Write the file trailer (after all frames are written)
void FFmpegWriter::WriteTrailer() {
    // Process final audio frame (if any)
    if (info.has_audio && audio_st)
        write_audio_packets(true, NULL);
 
    // Flush encoders (who sometimes hold on to frames)
    flush_encoders();
 
    if (info.has_audio && audio_st && audio_codec_ctx && audio_timestamp > 0) {
        audio_st->duration = av_rescale_q(
            audio_timestamp,
            audio_codec_ctx->time_base,
            audio_st->time_base);
    }
 
    /* write the trailer, if any. The trailer must be written
     * before you close the CodecContexts open when you wrote the
     * header; otherwise write_trailer may try to use memory that
     * was freed on av_codec_close() */
    av_write_trailer(oc);
 
    // Mark as 'written'
    write_trailer = true;
 
    Logger::Instance()->AppendDebugMethod("FFmpegWriter::WriteTrailer");
}
 
// Flush encoders
void FFmpegWriter::flush_encoders() {
    if (info.has_audio && audio_codec_ctx && AV_GET_CODEC_TYPE(audio_st) == AVMEDIA_TYPE_AUDIO && AV_GET_CODEC_ATTRIBUTES(audio_st, audio_codec_ctx)->frame_size <= 1)
        return;
#if (LIBAVFORMAT_VERSION_MAJOR < 58)
    // FFmpeg < 4.0
    if (info.has_video && video_codec_ctx && AV_GET_CODEC_TYPE(video_st) == AVMEDIA_TYPE_VIDEO && (oc->oformat->flags & AVFMT_RAWPICTURE) && AV_FIND_DECODER_CODEC_ID(video_st) == AV_CODEC_ID_RAWVIDEO)
        return;
#else
    if (info.has_video && video_codec_ctx && AV_GET_CODEC_TYPE(video_st) == AVMEDIA_TYPE_VIDEO && AV_FIND_DECODER_CODEC_ID(video_st) == AV_CODEC_ID_RAWVIDEO)
        return;
#endif
 
    // FLUSH VIDEO ENCODER
    if (info.has_video) {
        for (;;) {
 
            // Increment PTS (in frames and scaled to the codec's timebase)
            video_timestamp += av_rescale_q(1, av_make_q(info.fps.den, info.fps.num), video_codec_ctx->time_base);
 
#if IS_FFMPEG_3_2
            AVPacket* pkt = av_packet_alloc();
#else
            AVPacket* pkt;
            av_init_packet(pkt);
#endif
            pkt->data = NULL;
            pkt->size = 0;
 
            /* encode the image */
            int got_packet = 0;
            int error_code = 0;
 
#if IS_FFMPEG_3_2
            // Encode video packet (latest version of FFmpeg)
            error_code = avcodec_send_frame(video_codec_ctx, NULL);
            got_packet = 0;
            while (error_code >= 0) {
                error_code = avcodec_receive_packet(video_codec_ctx, pkt);
                if (error_code == AVERROR(EAGAIN)|| error_code == AVERROR_EOF) {
                    got_packet = 0;
                    // Write packet
                    avcodec_flush_buffers(video_codec_ctx);
                    break;
                }
                if (pkt->duration <= 0) {
                    pkt->duration = av_rescale_q(1, av_make_q(info.fps.den, info.fps.num), video_codec_ctx->time_base);
                }
                av_packet_rescale_ts(pkt, video_codec_ctx->time_base, video_st->time_base);
                pkt->stream_index = video_st->index;
                error_code = av_interleaved_write_frame(oc, pkt);
            }
#else // IS_FFMPEG_3_2
 
            // Encode video packet (older than FFmpeg 3.2)
            error_code = avcodec_encode_video2(video_codec_ctx, pkt, NULL, &got_packet);
 
#endif // IS_FFMPEG_3_2
 
            if (error_code < 0) {
                Logger::Instance()->AppendDebugMethod(
                    "FFmpegWriter::flush_encoders ERROR ["
                        + av_err2string(error_code) + "]",
                    "error_code", error_code);
            }
            if (!got_packet) {
                break;
            }
 
            // set the timestamp
            if (pkt->duration <= 0) {
                pkt->duration = av_rescale_q(1, av_make_q(info.fps.den, info.fps.num), video_codec_ctx->time_base);
            }
            av_packet_rescale_ts(pkt, video_codec_ctx->time_base, video_st->time_base);
            pkt->stream_index = video_st->index;
 
            // Write packet
            error_code = av_interleaved_write_frame(oc, pkt);
            if (error_code < 0) {
                Logger::Instance()->AppendDebugMethod(
                    "FFmpegWriter::flush_encoders ERROR ["
                        + av_err2string(error_code) + "]",
                    "error_code", error_code);
            }
        }
    }
 
    // FLUSH AUDIO ENCODER
    if (info.has_audio) {
        for (;;) {
#if IS_FFMPEG_3_2
            AVPacket* pkt = av_packet_alloc();
#else
            AVPacket* pkt;
            av_init_packet(pkt);
#endif
            pkt->data = NULL;
            pkt->size = 0;
            pkt->pts = pkt->dts = audio_timestamp;
 
            /* encode the image */
            int error_code = 0;
            int got_packet = 0;
#if IS_FFMPEG_3_2
            if (!audio_codec_ctx->codec || !(audio_codec_ctx->codec->capabilities & AV_CODEC_CAP_DELAY)) {
                av_packet_free(&pkt);
                break;
            }
            error_code = avcodec_send_frame(audio_codec_ctx, NULL);
            if (error_code < 0 && error_code != AVERROR_EOF) {
                Logger::Instance()->AppendDebugMethod(
                    "FFmpegWriter::flush_encoders ERROR ["
                        + av_err2string(error_code) + "]",
                    "error_code", error_code);
            }
            while (true) {
                error_code = avcodec_receive_packet(audio_codec_ctx, pkt);
                if (error_code == AVERROR(EAGAIN) || error_code == AVERROR_EOF) {
                    got_packet = 0;
                    break;
                }
                if (error_code < 0) {
                    Logger::Instance()->AppendDebugMethod(
                        "FFmpegWriter::flush_encoders ERROR ["
                            + av_err2string(error_code) + "]",
                        "error_code", error_code);
                    got_packet = 0;
                    break;
                }
 
                got_packet = 1;
                if (pkt->pts == AV_NOPTS_VALUE) {
                    pkt->pts = audio_timestamp;
                }
                if (pkt->dts == AV_NOPTS_VALUE) {
                    pkt->dts = pkt->pts;
                }
                if (pkt->duration <= 0) {
                    pkt->duration = audio_codec_ctx->frame_size > 0 ? audio_codec_ctx->frame_size : audio_input_frame_size;
                }
                av_packet_rescale_ts(pkt, audio_codec_ctx->time_base, audio_st->time_base);
                pkt->stream_index = audio_st->index;
                pkt->flags |= AV_PKT_FLAG_KEY;
 
                error_code = av_interleaved_write_frame(oc, pkt);
                if (error_code < 0) {
                    Logger::Instance()->AppendDebugMethod(
                        "FFmpegWriter::flush_encoders ERROR ["
                            + av_err2string(error_code) + "]",
                        "error_code", error_code);
                }
                // Flushing emits already-submitted samples; do not advance the input clock.
                AV_FREE_PACKET(pkt);
            }
            av_packet_free(&pkt);
            break;
#else
            error_code = avcodec_encode_audio2(audio_codec_ctx, pkt, NULL, &got_packet);
            if (error_code < 0) {
                Logger::Instance()->AppendDebugMethod(
                    "FFmpegWriter::flush_encoders ERROR ["
                        + av_err2string(error_code) + "]",
                    "error_code", error_code);
            }
            if (!got_packet) {
                break;
            }
 
            // Legacy encoding API timestamp fallback.
            pkt->pts = pkt->dts = audio_timestamp;
            if (pkt->duration <= 0) {
                pkt->duration = audio_codec_ctx->frame_size > 0 ? audio_codec_ctx->frame_size : audio_input_frame_size;
            }
 
            // Scale the PTS to the audio stream timebase (which is sometimes different than the codec's timebase)
            av_packet_rescale_ts(pkt, audio_codec_ctx->time_base, audio_st->time_base);
 
            // set stream
            pkt->stream_index = audio_st->index;
            pkt->flags |= AV_PKT_FLAG_KEY;
 
            // Write packet
            error_code = av_interleaved_write_frame(oc, pkt);
            if (error_code < 0) {
                Logger::Instance()->AppendDebugMethod(
                    "FFmpegWriter::flush_encoders ERROR ["
                        + av_err2string(error_code) + "]",
                    "error_code", error_code);
            }
 
            // Increment PTS by duration of packet
            audio_timestamp += pkt->duration;
 
            // deallocate memory for packet
            AV_FREE_PACKET(pkt);
#endif
        }
    }
 
}
 
// Close the video codec
void FFmpegWriter::close_video(AVFormatContext *oc, AVStream *st)
{
#if USE_HW_ACCEL
    if (hw_en_on && hw_en_supported) {
        if (hw_device_ctx) {
            av_buffer_unref(&hw_device_ctx);
            hw_device_ctx = NULL;
        }
    }
#endif // USE_HW_ACCEL
 
    // Free any previous memory allocations
    if (video_codec_ctx != nullptr) {
        AV_FREE_CONTEXT(video_codec_ctx);
        av_free(video_codec_ctx);
    }
}
 
// Close the audio codec
void FFmpegWriter::close_audio(AVFormatContext *oc, AVStream *st)
{
    // Clear buffers
    delete[] samples;
    delete[] audio_outbuf;
    delete[] audio_encoder_buffer;
    samples = NULL;
    audio_outbuf = NULL;
    audio_encoder_buffer = NULL;
 
    // Deallocate resample buffer
    if (avr) {
        SWR_CLOSE(avr);
        SWR_FREE(&avr);
        avr = NULL;
    }
 
    if (avr_planar) {
        SWR_CLOSE(avr_planar);
        SWR_FREE(&avr_planar);
        avr_planar = NULL;
    }
 
    // Free any previous memory allocations
    if (audio_codec_ctx != nullptr) {
        AV_FREE_CONTEXT(audio_codec_ctx);
        av_free(audio_codec_ctx);
    }
}
 
// Close the writer
void FFmpegWriter::Close() {
    // Write trailer (if needed). A failed header leaves nothing to finish.
    if (write_header && !write_trailer)
        WriteTrailer();
 
    // Close each codec
    if (video_st)
        close_video(oc, video_st);
    if (audio_st)
        close_audio(oc, audio_st);
 
    // Remove single software scaler
    if (img_convert_ctx)
        sws_freeContext(img_convert_ctx);
 
    if (!(oc->oformat->flags & AVFMT_NOFILE)) {
        /* close the output file */
        avio_close(oc->pb);
    }
 
    // Reset frame counters
    video_timestamp = 0;
    audio_timestamp = 0;
 
    // Free the context which frees the streams too
    avformat_free_context(oc);
    oc = NULL;
 
    // Close writer
    is_open = false;
    prepare_streams = false;
    write_header = false;
    write_trailer = false;
 
    Logger::Instance()->AppendDebugMethod("FFmpegWriter::Close");
}
 
// Add an AVFrame to the cache
void FFmpegWriter::add_avframe(std::shared_ptr<Frame> frame, AVFrame *av_frame) {
    // Add AVFrame to map (if it does not already exist)
    if (!av_frames.count(frame)) {
        // Add av_frame
        av_frames[frame] = av_frame;
    } else {
        // Do not add, and deallocate this AVFrame
        AV_FREE_FRAME(&av_frame);
    }
}
 
// Add an audio output stream
AVStream *FFmpegWriter::add_audio_stream() {
    // Find the audio codec
    const AVCodec *codec = avcodec_find_encoder_by_name(info.acodec.c_str());
    if (codec == NULL)
        throw InvalidCodec("A valid audio codec could not be found for this file.", path);
 
    // Free any previous memory allocations
    if (audio_codec_ctx != nullptr) {
        AV_FREE_CONTEXT(audio_codec_ctx);
    }
 
    // Create a new audio stream
    AVStream* st = avformat_new_stream(oc, codec);
    if (!st)
        throw OutOfMemory("Could not allocate memory for the audio stream.", path);
 
    // Allocate a new codec context for the stream
    ALLOC_CODEC_CTX(audio_codec_ctx, codec, st)
#if (LIBAVFORMAT_VERSION_MAJOR >= 58)
    st->codecpar->codec_id = codec->id;
#endif
    AVCodecContext* c = audio_codec_ctx;
 
    c->codec_id = codec->id;
    c->codec_type = AVMEDIA_TYPE_AUDIO;
 
    // Set the sample parameters
    c->bit_rate = info.audio_bit_rate;
#if !HAVE_CH_LAYOUT
    c->channels = info.channels;
#endif
 
    // Set valid sample rate (or throw error)
    if (const int* supported_rates = ffmpeg_codec_sample_rates(codec, c)) {
        int i;
        for (i = 0; supported_rates[i] != 0; i++)
            if (info.sample_rate == supported_rates[i]) {
                // Set the valid sample rate
                c->sample_rate = info.sample_rate;
                break;
            }
        if (supported_rates[i] == 0)
            throw InvalidSampleRate("An invalid sample rate was detected for this codec.", path);
    } else
        // Set sample rate
        c->sample_rate = info.sample_rate;
 
    c->time_base = AVRational{1, c->sample_rate};
    st->time_base = c->time_base;
 
    uint64_t channel_layout = info.channel_layout;
#if HAVE_CH_LAYOUT
    // Set a valid number of channels (or throw error)
    AVChannelLayout ch_layout = {};
    if (av_channel_layout_from_mask(&ch_layout, info.channel_layout) < 0)
        throw InvalidChannels("An invalid channel layout was detected (i.e. MONO / STEREO).", path);
    if (const AVChannelLayout* codec_layouts = ffmpeg_codec_ch_layouts(codec, c)) {
        int i;
        for (i = 0; av_channel_layout_check(&codec_layouts[i]); i++)
            if (av_channel_layout_compare(&ch_layout, &codec_layouts[i]) == 0) {
                // Set valid channel layout
                av_channel_layout_copy(&c->ch_layout, &ch_layout);
                break;
            }
        if (!av_channel_layout_check(&codec_layouts[i]))
            throw InvalidChannels("An invalid channel layout was detected (i.e. MONO / STEREO).", path);
    } else {
        // Set valid channel layout
        av_channel_layout_copy(&c->ch_layout, &ch_layout);
    }
#else
    // Preserve validation on FFmpeg versions using legacy channel masks.
    if (codec->channel_layouts) {
        const uint64_t* layout = codec->channel_layouts;
        while (*layout != 0 && *layout != channel_layout)
            ++layout;
        if (*layout == 0)
            throw InvalidChannels("An invalid channel layout was detected (i.e. MONO / STEREO).", path);
    }
    c->channel_layout = channel_layout;
#endif
 
    // Choose a valid sample_fmt
    if (const AVSampleFormat* codec_fmts = ffmpeg_codec_sample_fmts(codec, c)) {
        for (int i = 0; codec_fmts[i] != AV_SAMPLE_FMT_NONE; i++) {
            // Set sample format to 1st valid format (and then exit loop)
            c->sample_fmt = codec_fmts[i];
            break;
        }
    }
    if (c->sample_fmt == AV_SAMPLE_FMT_NONE) {
        // Default if no sample formats found
        c->sample_fmt = AV_SAMPLE_FMT_S16;
    }
 
    // some formats want stream headers to be separate
    if (oc->oformat->flags & AVFMT_GLOBALHEADER)
#if (LIBAVCODEC_VERSION_MAJOR >= 57)
        // FFmpeg 3.0+
        c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
#else
        c->flags |= CODEC_FLAG_GLOBAL_HEADER;
#endif
 
    AV_COPY_PARAMS_FROM_CONTEXT(st, c);
 
    int nb_channels;
    const char* nb_channels_label;
    const char* channel_layout_label;
 
#if HAVE_CH_LAYOUT
    nb_channels = c->ch_layout.nb_channels;
    channel_layout = c->ch_layout.u.mask;
    nb_channels_label = "c->ch_layout.nb_channels";
    channel_layout_label = "c->ch_layout.u.mask";
#else
    nb_channels = c->channels;
    nb_channels_label = "c->channels";
    channel_layout_label = "c->channel_layout";
#endif
 
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::add_audio_stream",
        "c->codec_id", c->codec_id,
        "c->bit_rate", c->bit_rate,
        nb_channels_label, nb_channels,
        "c->sample_fmt", c->sample_fmt,
        channel_layout_label, channel_layout,
        "c->sample_rate", c->sample_rate);
 
    return st;
}
 
// Add a video output stream
AVStream *FFmpegWriter::add_video_stream() {
    // Find the video codec
    const AVCodec *codec = avcodec_find_encoder_by_name(info.vcodec.c_str());
    if (codec == NULL)
        throw InvalidCodec("A valid video codec could not be found for this file.", path);
 
    // Free any previous memory allocations
    if (video_codec_ctx != nullptr) {
        AV_FREE_CONTEXT(video_codec_ctx);
    }
 
    // Create a new video stream
    AVStream* st = avformat_new_stream(oc, codec);
    if (!st)
        throw OutOfMemory("Could not allocate memory for the video stream.", path);
 
    // Allocate a new codec context for the stream
    ALLOC_CODEC_CTX(video_codec_ctx, codec, st)
#if (LIBAVFORMAT_VERSION_MAJOR >= 58)
    st->codecpar->codec_id = codec->id;
#endif
 
    AVCodecContext* c = video_codec_ctx;
 
    c->codec_id = codec->id;
    c->codec_type = AVMEDIA_TYPE_VIDEO;
 
    // Set sample aspect ratio
    c->sample_aspect_ratio.num = info.pixel_ratio.num;
    c->sample_aspect_ratio.den = info.pixel_ratio.den;
 
    /* Init video encoder options */
    if (info.video_bit_rate >= 1000
#if (LIBAVCODEC_VERSION_MAJOR >= 58)
        && c->codec_id != AV_CODEC_ID_AV1
#endif
        ) {
        c->bit_rate = info.video_bit_rate;
        if (info.video_bit_rate >= 1500000) {
            if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO)  {
                c->qmin = 2;
                c->qmax = 30;
            }
        }
        // Here should be the setting for low fixed bitrate
        // Defaults are used because mpeg2 otherwise had problems
    } else {
        // Check if codec supports crf or qp
        switch (c->codec_id) {
#if (LIBAVCODEC_VERSION_MAJOR >= 58)
            // FFmpeg 4.0+
            case AV_CODEC_ID_AV1 :
            // TODO: Set `crf` or `qp` according to bitrate, as bitrate is not supported by these encoders yet.
            if (info.video_bit_rate >= 1000) {
                c->bit_rate = 0;
                if (strstr(info.vcodec.c_str(), "aom") != NULL) {
                    int calculated_quality = 35;
                    if (info.video_bit_rate < 500000) calculated_quality = 50;
                    if (info.video_bit_rate > 5000000) calculated_quality = 10;
                    av_opt_set_int(c->priv_data, "crf", calculated_quality, 0);
                    info.video_bit_rate = calculated_quality;
                } else {
                    int calculated_quality = 50;
                    if (info.video_bit_rate < 500000) calculated_quality = 60;
                    if (info.video_bit_rate > 5000000) calculated_quality = 15;
                    av_opt_set_int(c->priv_data, "qp", calculated_quality, 0);
                    info.video_bit_rate = calculated_quality;
                } // medium
            }
            if (strstr(info.vcodec.c_str(), "svtav1") != NULL) {
                av_opt_set_int(c->priv_data, "preset", 6, 0);
                av_opt_set_int(c->priv_data, "forced-idr",1,0);
            }
            else if (strstr(info.vcodec.c_str(), "rav1e") != NULL) {
                av_opt_set_int(c->priv_data, "speed", 7, 0);
                av_opt_set_int(c->priv_data, "tile-rows", 2, 0);
                av_opt_set_int(c->priv_data, "tile-columns", 4, 0);
            }
            else if (strstr(info.vcodec.c_str(), "aom") != NULL) {
                // Set number of tiles to a fixed value
                // TODO: Allow user to chose their own number of tiles
                av_opt_set_int(c->priv_data, "tile-rows", 1, 0);        // log2 of number of rows
                av_opt_set_int(c->priv_data, "tile-columns", 2, 0);     // log2 of number of columns
                av_opt_set_int(c->priv_data, "row-mt", 1, 0);           // use multiple cores
                av_opt_set_int(c->priv_data, "cpu-used", 3, 0);         // default is 1, usable is 4
            }
            //break;
#endif
            case AV_CODEC_ID_VP9 :
            case AV_CODEC_ID_HEVC :
            case AV_CODEC_ID_VP8 :
            case AV_CODEC_ID_H264 :
                if (info.video_bit_rate < 40) {
                    c->qmin = 0;
                    c->qmax = 63;
                } else {
                    c->qmin = info.video_bit_rate - 5;
                    c->qmax = 63;
                }
                break;
            default:
                // Here should be the setting for codecs that don't support crf
                // For now defaults are used
                break;
        }
    }
 
    //TODO: Implement variable bitrate feature (which actually works). This implementation throws
    //invalid bitrate errors and rc buffer underflow errors, etc...
    //c->rc_min_rate = info.video_bit_rate;
    //c->rc_max_rate = info.video_bit_rate;
    //c->rc_buffer_size = FFMAX(c->rc_max_rate, 15000000) * 112L / 15000000 * 16384;
    //if ( !c->rc_initial_buffer_occupancy )
    //  c->rc_initial_buffer_occupancy = c->rc_buffer_size * 3/4;
 
    /* resolution must be a multiple of two */
    // TODO: require /2 height and width
    c->width = info.width;
    c->height = info.height;
 
    /* time base: this is the fundamental unit of time (in seconds) in terms
     of which frame timestamps are represented. for fixed-fps content,
     timebase should be 1/framerate and timestamp increments should be
     identically 1. */
    c->time_base.num = info.video_timebase.num;
    c->time_base.den = info.video_timebase.den;
// AVCodecContext->framerate was added in FFmpeg 2.6
#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(56, 26, 0)
    c->framerate = av_inv_q(c->time_base);
#endif
    st->avg_frame_rate = av_inv_q(c->time_base);
    st->r_frame_rate = av_inv_q(c->time_base);
    st->time_base.num = info.video_timebase.num;
    st->time_base.den = info.video_timebase.den;
 
    c->gop_size = 12; /* TODO: add this to "info"... emit one intra frame every twelve frames at most */
    c->max_b_frames = 10;
    if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO)
        /* just for testing, we also add B frames */
        c->max_b_frames = 2;
    if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO)
        /* Needed to avoid using macroblocks in which some coeffs overflow.
         This does not happen with normal video, it just happens here as
         the motion of the chroma plane does not match the luma plane. */
        c->mb_decision = 2;
    // some formats want stream headers to be separate
    if (oc->oformat->flags & AVFMT_GLOBALHEADER)
#if (LIBAVCODEC_VERSION_MAJOR >= 57)
        // FFmpeg 3.0+
        c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
#else
        c->flags |= CODEC_FLAG_GLOBAL_HEADER;
#endif
 
    // Find all supported pixel formats for this codec
    if (const PixelFormat* supported_pixel_formats = ffmpeg_codec_pix_fmts(codec, c)) {
        while (*supported_pixel_formats != PIX_FMT_NONE) {
            // Assign the 1st valid pixel format (if one is missing)
            if (c->pix_fmt == PIX_FMT_NONE)
                c->pix_fmt = *supported_pixel_formats;
            ++supported_pixel_formats;
        }
    }
 
    // Codec doesn't have any pix formats?
    if (c->pix_fmt == PIX_FMT_NONE) {
        if (oc->oformat->video_codec == AV_CODEC_ID_RAWVIDEO) {
            // Raw video should use RGB24
            c->pix_fmt = PIX_FMT_RGB24;
 
#if (LIBAVFORMAT_VERSION_MAJOR < 58)
            // FFmpeg < 4.0
            if (strcmp(oc->oformat->name, "gif") != 0)
                // If not GIF format, skip the encoding process
                // Set raw picture flag (so we don't encode this video)
                oc->oformat->flags |= AVFMT_RAWPICTURE;
#endif
        } else {
            // Set the default codec
            c->pix_fmt = PIX_FMT_YUV420P;
        }
    }
 
    AV_COPY_PARAMS_FROM_CONTEXT(st, c);
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::add_video_stream ("
            + (std::string)oc->oformat->name + " : "
            + (std::string)av_get_pix_fmt_name(c->pix_fmt) + ")",
        "c->codec_id", c->codec_id,
        "c->bit_rate", c->bit_rate,
        "c->pix_fmt", c->pix_fmt,
        "oc->oformat->flags", oc->oformat->flags);
    return st;
}
 
// open audio codec
void FFmpegWriter::open_audio(AVFormatContext *oc, AVStream *st) {
    const AVCodec *codec;
    AV_GET_CODEC_FROM_STREAM(st, audio_codec_ctx)
 
    // Audio encoding does not typically use more than 2 threads (most codecs use 1 thread)
    audio_codec_ctx->thread_count = std::min(FF_AUDIO_NUM_PROCESSORS, 2);
 
    // Find the audio encoder
    codec = avcodec_find_encoder_by_name(info.acodec.c_str());
    if (!codec)
        codec = avcodec_find_encoder(audio_codec_ctx->codec_id);
    if (!codec)
        throw InvalidCodec("Could not find codec", path);
 
    // Init options
    AVDictionary *opts = NULL;
    av_dict_set(&opts, "strict", "experimental", 0);
 
    // Open the codec
    if (avcodec_open2(audio_codec_ctx, codec, &opts) < 0)
        throw InvalidCodec("Could not open audio codec", path);
    AV_COPY_PARAMS_FROM_CONTEXT(st, audio_codec_ctx);
 
    // Free options
    av_dict_free(&opts);
 
    // Calculate the size of the input frame (i..e how many samples per packet), and the output buffer
    // TODO: Ugly hack for PCM codecs (will be removed ASAP with new PCM support to compute the input frame size in samples
    if (audio_codec_ctx->frame_size <= 1) {
        // No frame size found... so calculate
        audio_input_frame_size = 50000 / info.channels;
 
        int s = AV_FIND_DECODER_CODEC_ID(st);
        switch (s) {
            case AV_CODEC_ID_PCM_S16LE:
            case AV_CODEC_ID_PCM_S16BE:
            case AV_CODEC_ID_PCM_U16LE:
            case AV_CODEC_ID_PCM_U16BE:
                audio_input_frame_size >>= 1;
                break;
            default:
                break;
        }
    } else {
        // Set frame size based on the codec
        audio_input_frame_size = audio_codec_ctx->frame_size;
    }
 
    // Set the initial frame size (since it might change during resampling)
    initial_audio_input_frame_size = audio_input_frame_size;
 
    // Allocate array for samples
    samples = new int16_t[AVCODEC_MAX_AUDIO_FRAME_SIZE];
 
    // Set audio output buffer (used to store the encoded audio)
    audio_outbuf_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
    audio_outbuf = new uint8_t[audio_outbuf_size];
 
    // Set audio packet encoding buffer
    audio_encoder_buffer_size = AUDIO_PACKET_ENCODING_SIZE;
    audio_encoder_buffer = new uint8_t[audio_encoder_buffer_size];
 
    // Add audio metadata (if any)
    for (std::map<std::string, std::string>::iterator iter = info.metadata.begin(); iter != info.metadata.end(); ++iter) {
        av_dict_set(&st->metadata, iter->first.c_str(), iter->second.c_str(), 0);
    }
 
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::open_audio",
        "audio_codec_ctx->thread_count", audio_codec_ctx->thread_count,
        "audio_input_frame_size", audio_input_frame_size,
        "buffer_size", AVCODEC_MAX_AUDIO_FRAME_SIZE + MY_INPUT_BUFFER_PADDING_SIZE);
}
 
// open video codec
void FFmpegWriter::open_video(AVFormatContext *oc, AVStream *st) {
    const AVCodec *codec;
    AV_GET_CODEC_FROM_STREAM(st, video_codec_ctx)
 
    // Set number of threads equal to number of processors (not to exceed 16, FFmpeg doesn't recommend more than 16)
    video_codec_ctx->thread_count = std::min(FF_VIDEO_NUM_PROCESSORS, 16);
 
#if USE_HW_ACCEL
    if (hw_en_on && hw_en_supported) {
        //char *dev_hw = NULL;
        char adapter[256];
        char *adapter_ptr = NULL;
        int adapter_num;
        // Use the hw device given in the environment variable HW_EN_DEVICE_SET or the default if not set
        adapter_num = openshot::Settings::Instance()->HW_EN_DEVICE_SET;
        std::clog << "Encoding Device Nr: " << adapter_num << "\n";
        if (adapter_num < 3 && adapter_num >=0) {
#if defined(__linux__)
                snprintf(adapter,sizeof(adapter),"/dev/dri/renderD%d", adapter_num+128);
                // Maybe 127 is better because the first card would be 1?!
                adapter_ptr = adapter;
#elif defined(_WIN32) || defined(__APPLE__)
                adapter_ptr = NULL;
#endif
            }
            else {
                adapter_ptr = NULL; // Just to be sure
            }
// Check if it is there and writable
#if defined(__linux__)
        if( adapter_ptr != NULL && access( adapter_ptr, W_OK ) == 0 ) {
#elif defined(_WIN32) || defined(__APPLE__)
        if( adapter_ptr != NULL ) {
#endif
            Logger::Instance()->AppendDebugMethod(
                "Encode Device present using device",
                "adapter", adapter_num);
        }
        else {
            adapter_ptr = NULL;  // use default
            Logger::Instance()->AppendDebugMethod(
                "Encode Device not present, using default");
        }
        if (av_hwdevice_ctx_create(&hw_device_ctx,
                hw_en_av_device_type, adapter_ptr, NULL, 0) < 0)
        {
            Logger::Instance()->AppendDebugMethod(
                "FFmpegWriter::open_video ERROR creating hwdevice, Codec name:",
                info.vcodec.c_str(), -1);
            throw InvalidCodec("Could not create hwdevice", path);
        }
    }
#endif // USE_HW_ACCEL
 
    /* find the video encoder */
    codec = avcodec_find_encoder_by_name(info.vcodec.c_str());
    if (!codec)
        codec = avcodec_find_encoder(AV_FIND_DECODER_CODEC_ID(st));
    if (!codec)
        throw InvalidCodec("Could not find codec", path);
 
    /* Legacy behavior: force max_b_frames to 0 for many codecs.
     * This can be disabled via SetOption(VIDEO_STREAM, "allow_b_frames", "1"). */
    if (!allow_b_frames && video_codec_ctx->max_b_frames &&
        video_codec_ctx->codec_id != AV_CODEC_ID_MPEG4 &&
        video_codec_ctx->codec_id != AV_CODEC_ID_MPEG1VIDEO &&
        video_codec_ctx->codec_id != AV_CODEC_ID_MPEG2VIDEO)
        video_codec_ctx->max_b_frames = 0;
 
    // Init options
    AVDictionary *opts = NULL;
    av_dict_set(&opts, "strict", "experimental", 0);
 
#if USE_HW_ACCEL
    if (hw_en_on && hw_en_supported) {
        video_codec_ctx->pix_fmt   = hw_en_av_pix_fmt;
 
        // for the list of possible options, see the list of codec-specific options:
        // e.g. ffmpeg -h encoder=h264_vaapi or ffmpeg -h encoder=hevc_vaapi
        // and "man ffmpeg-codecs"
 
        // For VAAPI, it is safer to explicitly set rc_mode instead of relying on auto-selection
        // which is ffmpeg version-specific.
        if (hw_en_av_pix_fmt == AV_PIX_FMT_VAAPI) {
            int64_t qp;
            if (av_opt_get_int(video_codec_ctx->priv_data, "qp", 0, &qp) != 0 || qp == 0) {
                // unless "qp" was set for CQP, switch to VBR RC mode
                av_opt_set(video_codec_ctx->priv_data, "rc_mode", "VBR", 0);
 
                // In the current state (ffmpeg-4.2-4 libva-mesa-driver-19.1.5-1) to use VBR,
                // one has to specify both bit_rate and maxrate, otherwise a small low quality file is generated on Intel iGPU).
                video_codec_ctx->rc_max_rate = video_codec_ctx->bit_rate;
            }
        }
 
        switch (video_codec_ctx->codec_id) {
            case AV_CODEC_ID_H264:
                video_codec_ctx->max_b_frames = 0;  // At least this GPU doesn't support b-frames
                video_codec_ctx->profile = AV_PROFILE_H264_CONSTRAINED_BASELINE;
                av_opt_set(video_codec_ctx->priv_data, "preset", "slow", 0);
                av_opt_set(video_codec_ctx->priv_data, "tune", "zerolatency", 0);
                av_opt_set(video_codec_ctx->priv_data, "vprofile", "baseline", AV_OPT_SEARCH_CHILDREN);
                break;
            case AV_CODEC_ID_HEVC:
                // tested to work with defaults
                break;
            case AV_CODEC_ID_VP9:
                // tested to work with defaults
                break;
            default:
                Logger::Instance()->AppendDebugMethod(
                    "No codec-specific options defined for this codec. HW encoding may fail",
                    "codec_id", video_codec_ctx->codec_id);
                break;
        }
 
        // set hw_frames_ctx for encoder's AVCodecContext
        int err;
        if ((err = set_hwframe_ctx(video_codec_ctx, hw_device_ctx, info.width, info.height)) < 0)
        {
            Logger::Instance()->AppendDebugMethod(
                "FFmpegWriter::open_video (set_hwframe_ctx) ERROR faled to set hwframe context",
                "width", info.width,
                "height", info.height,
                av_err2string(err), -1);
        }
    }
#endif // USE_HW_ACCEL
 
// Set libx265 hvc1 tag (for Apple playback compatibility).
#if USE_HW_ACCEL
        if (!(hw_en_on && hw_en_supported) && video_codec_ctx->codec_id == AV_CODEC_ID_HEVC) {
            video_codec_ctx->codec_tag = MKTAG('h', 'v', 'c', '1');
        }
#else
        if (video_codec_ctx->codec_id == AV_CODEC_ID_HEVC) {
            video_codec_ctx->codec_tag = MKTAG('h', 'v', 'c', '1');
        }
#endif
 
    /* open the codec */
    if (avcodec_open2(video_codec_ctx, codec, &opts) < 0)
        throw InvalidCodec("Could not open video codec", path);
    AV_COPY_PARAMS_FROM_CONTEXT(st, video_codec_ctx);
    st->avg_frame_rate = av_make_q(info.fps.num, info.fps.den);
    st->r_frame_rate = av_make_q(info.fps.num, info.fps.den);
 
    // Free options
    av_dict_free(&opts);
 
    // Add video metadata (if any)
    for (auto iter = info.metadata.begin(); iter != info.metadata.end(); ++iter) {
        av_dict_set(&st->metadata, iter->first.c_str(), iter->second.c_str(), 0);
    }
 
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::open_video",
        "video_codec_ctx->thread_count", video_codec_ctx->thread_count);
 
}
 
// write all queued frames' audio to the video file
void FFmpegWriter::write_audio_packets(bool is_final, std::shared_ptr<openshot::Frame> frame) {
    if (!frame && !is_final)
        return;
 
    // Init audio buffers / variables
    int total_frame_samples = 0;
    int frame_position = 0;
    int channels_in_frame = 0;
    int sample_rate_in_frame = 0;
    int samples_in_frame = 0;
    ChannelLayout channel_layout_in_frame = LAYOUT_MONO; // default channel layout
 
    // Create a new array (to hold all float audio samples, for the current queued frames
    unsigned int all_queued_samples_size = sizeof(float) * AVCODEC_MAX_AUDIO_FRAME_SIZE;
    float *all_queued_samples = (float *) av_malloc(all_queued_samples_size);
    int16_t *all_resampled_samples = NULL;
    int16_t *final_samples_planar = NULL;
    int16_t *final_samples = NULL;
 
    // Get audio sample array
    float *frame_samples_float = NULL;
 
    // Get the audio details from this frame
    if (frame) {
        sample_rate_in_frame = frame->SampleRate();
        samples_in_frame = frame->GetAudioSamplesCount();
        channels_in_frame = frame->GetAudioChannelsCount();
        channel_layout_in_frame = frame->ChannelsLayout();
 
        // Get samples interleaved together (c1 c2 c1 c2 c1 c2)
        frame_samples_float = frame->GetInterleavedAudioSamples(&samples_in_frame);
    }
 
    // Calculate total samples
    total_frame_samples = samples_in_frame * channels_in_frame;
 
    // Keep samples as floats, so float codecs (such as AAC) are not limited to
    // 16 bits or clipped early. Integer codecs are converted by the resampler.
    for (int s = 0; s < total_frame_samples; s++, frame_position++)
        all_queued_samples[frame_position] = frame_samples_float[s];
 
    // Deallocate float array
    delete[] frame_samples_float;
 
 
    // Update total samples (since we've combined all queued frames)
    total_frame_samples = frame_position;
    int remaining_frame_samples = total_frame_samples;
    int samples_position = 0;
 
 
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::write_audio_packets",
        "is_final", is_final,
        "total_frame_samples", total_frame_samples,
        "channel_layout_in_frame", channel_layout_in_frame,
        "channels_in_frame", channels_in_frame,
        "samples_in_frame", samples_in_frame,
        "LAYOUT_MONO", LAYOUT_MONO);
 
    // Keep track of the original sample format
    AVSampleFormat output_sample_fmt = audio_codec_ctx->sample_fmt;
 
    AVFrame *audio_frame = NULL;
    if (!is_final) {
        // Create input frame (and allocate arrays)
        audio_frame = AV_ALLOCATE_FRAME();
        AV_RESET_FRAME(audio_frame);
        audio_frame->nb_samples = total_frame_samples / channels_in_frame;
 
        // Fill input frame with sample data
        int error_code = avcodec_fill_audio_frame(audio_frame, channels_in_frame, AV_SAMPLE_FMT_FLT, (uint8_t *) all_queued_samples, all_queued_samples_size, 0);
        if (error_code < 0) {
            Logger::Instance()->AppendDebugMethod(
                "FFmpegWriter::write_audio_packets ERROR ["
                    + av_err2string(error_code) + "]",
                "error_code", error_code);
        }
 
        // Do not convert audio to planar format (yet). We need to keep everything interleaved at this point.
        switch (audio_codec_ctx->sample_fmt) {
            case AV_SAMPLE_FMT_FLTP: {
                output_sample_fmt = AV_SAMPLE_FMT_FLT;
                break;
            }
            case AV_SAMPLE_FMT_S32P: {
                output_sample_fmt = AV_SAMPLE_FMT_S32;
                break;
            }
            case AV_SAMPLE_FMT_S16P: {
                output_sample_fmt = AV_SAMPLE_FMT_S16;
                break;
            }
            case AV_SAMPLE_FMT_U8P: {
                output_sample_fmt = AV_SAMPLE_FMT_U8;
                break;
            }
            default: {
                // This is only here to silence unused-enum warnings
                break;
            }
        }
 
        // Update total samples & input frame size (due to bigger or smaller data types)
        total_frame_samples *= (float(info.sample_rate) / sample_rate_in_frame); // adjust for different byte sizes
        total_frame_samples *= (float(info.channels) / channels_in_frame); // adjust for different # of channels
 
        // Create output frame (and allocate arrays)
        AVFrame *audio_converted = AV_ALLOCATE_FRAME();
        AV_RESET_FRAME(audio_converted);
        audio_converted->nb_samples = total_frame_samples / info.channels;
        av_samples_alloc(audio_converted->data, audio_converted->linesize, info.channels, audio_converted->nb_samples, output_sample_fmt, 0);
 
        Logger::Instance()->AppendDebugMethod(
            "FFmpegWriter::write_audio_packets (1st resampling)",
            "in_sample_fmt", AV_SAMPLE_FMT_FLT,
            "out_sample_fmt", output_sample_fmt,
            "in_sample_rate", sample_rate_in_frame,
            "out_sample_rate", info.sample_rate,
            "in_channels", channels_in_frame,
            "out_channels", info.channels);
 
        // setup resample context
        if (!avr) {
            avr = SWR_ALLOC();
#if HAVE_CH_LAYOUT
            AVChannelLayout in_chlayout = ffmpeg_default_channel_layout(channels_in_frame);
            AVChannelLayout out_chlayout = ffmpeg_default_channel_layout(info.channels);
            if (channel_layout_in_frame > 0) {
                av_channel_layout_from_mask(&in_chlayout, channel_layout_in_frame);
            }
            if (info.channel_layout > 0) {
                av_channel_layout_from_mask(&out_chlayout, info.channel_layout);
            }
            av_opt_set_chlayout(avr, "in_chlayout", &in_chlayout, 0);
            av_opt_set_chlayout(avr, "out_chlayout", &out_chlayout, 0);
#else
            av_opt_set_int(avr, "in_channel_layout", channel_layout_in_frame, 0);
            av_opt_set_int(avr, "out_channel_layout", info.channel_layout, 0);
            av_opt_set_int(avr, "in_channels", channels_in_frame, 0);
            av_opt_set_int(avr, "out_channels", info.channels, 0);
#endif
            av_opt_set_int(avr, "in_sample_fmt", AV_SAMPLE_FMT_FLT, 0);
            av_opt_set_int(avr, "out_sample_fmt", output_sample_fmt, 0); // planar not allowed here
            av_opt_set_int(avr, "in_sample_rate", sample_rate_in_frame, 0);
            av_opt_set_int(avr, "out_sample_rate", info.sample_rate, 0);
            if (channels_in_frame == 1 && info.channels == 2) {
                // FFmpeg's default mono to stereo mix lowers each side by 3 dB. Copy
                // mono to both sides at full level, like media players do.
                const double mono_to_stereo[2] = { 1.0, 1.0 };
#if USE_SW
                swr_set_matrix(avr, mono_to_stereo, 1);
#else
                avresample_set_matrix(avr, mono_to_stereo, 1);
#endif
            }
            SWR_INIT(avr);
        }
        // Convert audio samples
        int nb_samples = SWR_CONVERT(
            avr,    // audio resample context
            audio_converted->data,         // output data pointers
            audio_converted->linesize[0],   // output plane size, in bytes. (0 if unknown)
            audio_converted->nb_samples,     // maximum number of samples that the output buffer can hold
            audio_frame->data,             // input data pointers
            audio_frame->linesize[0],       // input plane size, in bytes (0 if unknown)
            audio_frame->nb_samples     // number of input samples to convert
        );
 
        // Resampling can buffer samples internally. Only copy samples actually
        // returned, not the estimated capacity (which can read past the buffer).
        if (nb_samples < 0)
            throw ErrorEncodingAudio("Could not resample audio", nb_samples);
        remaining_frame_samples = nb_samples * info.channels;
 
        // Create a new array (to hold all resampled S16 audio samples)
        all_resampled_samples = (int16_t *) av_malloc(
            sizeof(int16_t) * nb_samples * info.channels
            * (av_get_bytes_per_sample(output_sample_fmt) /
               av_get_bytes_per_sample(AV_SAMPLE_FMT_S16) )
        );
 
        // Copy audio samples over original samples
        memcpy(all_resampled_samples, audio_converted->data[0],
               static_cast<size_t>(nb_samples)
                   * info.channels
                   * av_get_bytes_per_sample(output_sample_fmt));
 
        // Remove converted audio
        av_freep(&(audio_frame->data[0]));
        AV_FREE_FRAME(&audio_frame);
        av_freep(&audio_converted->data[0]);
        AV_FREE_FRAME(&audio_converted);
        all_queued_samples = NULL; // this array cleared with above call
 
        Logger::Instance()->AppendDebugMethod(
            "FFmpegWriter::write_audio_packets (Successfully completed 1st resampling)",
            "nb_samples", nb_samples,
            "remaining_frame_samples", remaining_frame_samples);
    }
 
    if (is_final && remaining_frame_samples <= 0 && audio_input_position <= 0) {
        if (all_queued_samples) {
            av_freep(&all_queued_samples);
        }
        return;
    }
 
    // Loop until no more samples
    while (remaining_frame_samples > 0 || is_final) {
        // Get remaining samples needed for this packet
        int remaining_packet_samples = (audio_input_frame_size * info.channels) - audio_input_position;
 
        // Determine how many samples we need
        int diff = 0;
        if (remaining_frame_samples >= remaining_packet_samples) {
            diff = remaining_packet_samples;
        } else {
            diff = remaining_frame_samples;
        }
 
        // Copy frame samples into the packet samples array
        if (!is_final)
            //TODO: Make this more sane
            memcpy(
                samples + (audio_input_position
                    * (av_get_bytes_per_sample(output_sample_fmt) /
                       av_get_bytes_per_sample(AV_SAMPLE_FMT_S16) )
                ),
                all_resampled_samples + samples_position,
                static_cast<size_t>(diff)
                    * av_get_bytes_per_sample(output_sample_fmt)
            );
 
        // Increment counters
        audio_input_position += diff;
        samples_position += diff * (av_get_bytes_per_sample(output_sample_fmt) / av_get_bytes_per_sample(AV_SAMPLE_FMT_S16));
        remaining_frame_samples -= diff;
 
        // Do we have enough samples to proceed?
        if (audio_input_position < (audio_input_frame_size * info.channels) && !is_final)
            // Not enough samples to encode... so wait until the next frame
            break;
 
        // Convert to planar (if needed by audio codec)
        AVFrame *frame_final = AV_ALLOCATE_FRAME();
        AV_RESET_FRAME(frame_final);
        const int frame_nb_samples = audio_input_position / info.channels;
        if (av_sample_fmt_is_planar(audio_codec_ctx->sample_fmt)) {
            Logger::Instance()->AppendDebugMethod(
                "FFmpegWriter::write_audio_packets (2nd resampling for Planar formats)",
                "in_sample_fmt", output_sample_fmt,
                "out_sample_fmt", audio_codec_ctx->sample_fmt,
                "in_sample_rate", info.sample_rate,
                "out_sample_rate", info.sample_rate,
                "in_channels", info.channels,
                "out_channels", info.channels
            );
 
            // setup resample context
            if (!avr_planar) {
                avr_planar = SWR_ALLOC();
#if HAVE_CH_LAYOUT
                AVChannelLayout layout = ffmpeg_default_channel_layout(info.channels);
                if (info.channel_layout > 0) {
                    av_channel_layout_from_mask(&layout, info.channel_layout);
                }
                av_opt_set_chlayout(avr_planar, "in_chlayout", &layout, 0);
                av_opt_set_chlayout(avr_planar, "out_chlayout", &layout, 0);
#else
                av_opt_set_int(avr_planar, "in_channel_layout", info.channel_layout, 0);
                av_opt_set_int(avr_planar, "out_channel_layout", info.channel_layout, 0);
                av_opt_set_int(avr_planar, "in_channels", info.channels, 0);
                av_opt_set_int(avr_planar, "out_channels", info.channels, 0);
#endif
                av_opt_set_int(avr_planar, "in_sample_fmt", output_sample_fmt, 0);
                av_opt_set_int(avr_planar, "out_sample_fmt", audio_codec_ctx->sample_fmt, 0); // planar not allowed here
                av_opt_set_int(avr_planar, "in_sample_rate", info.sample_rate, 0);
                av_opt_set_int(avr_planar, "out_sample_rate", info.sample_rate, 0);
                SWR_INIT(avr_planar);
            }
 
            // Create input frame (and allocate arrays)
            audio_frame = AV_ALLOCATE_FRAME();
            AV_RESET_FRAME(audio_frame);
            audio_frame->nb_samples = audio_input_position / info.channels;
 
            // Create a new array
            final_samples_planar = (int16_t *) av_malloc(
                sizeof(int16_t) * audio_frame->nb_samples * info.channels
                * (av_get_bytes_per_sample(output_sample_fmt) /
                   av_get_bytes_per_sample(AV_SAMPLE_FMT_S16) )
            );
 
            // Copy audio into buffer for frame
            memcpy(final_samples_planar, samples,
                   static_cast<size_t>(audio_frame->nb_samples)
                       * info.channels
                       * av_get_bytes_per_sample(output_sample_fmt));
 
            // Fill input frame with sample data
            avcodec_fill_audio_frame(audio_frame, info.channels, output_sample_fmt,
                (uint8_t *) final_samples_planar, audio_encoder_buffer_size, 0);
 
            // Create output frame (and allocate arrays)
            frame_final->nb_samples = frame_nb_samples;
#if HAVE_CH_LAYOUT
            av_channel_layout_from_mask(&frame_final->ch_layout, info.channel_layout);
#else
            frame_final->channels = info.channels;
            frame_final->channel_layout = info.channel_layout;
#endif
            frame_final->format = audio_codec_ctx->sample_fmt;
            av_samples_alloc(frame_final->data, frame_final->linesize, info.channels,
                frame_final->nb_samples, audio_codec_ctx->sample_fmt, 0);
 
            // Convert audio samples
            int nb_samples = SWR_CONVERT(
                avr_planar,               // audio resample context
                frame_final->data,         // output data pointers
                frame_final->linesize[0],   // output plane size, in bytes. (0 if unknown)
                frame_final->nb_samples,     // maximum number of samples that the output buffer can hold
                audio_frame->data,         // input data pointers
                audio_frame->linesize[0],   // input plane size, in bytes (0 if unknown)
                audio_frame->nb_samples   // number of input samples to convert
            );
 
            // Copy audio samples over original samples
            const auto copy_length = static_cast<size_t>(nb_samples)
                * av_get_bytes_per_sample(audio_codec_ctx->sample_fmt)
                * info.channels;
 
            if (nb_samples > 0)
                memcpy(samples, frame_final->data[0], copy_length);
 
            // deallocate AVFrame
            av_freep(&(audio_frame->data[0]));
            AV_FREE_FRAME(&audio_frame);
            all_queued_samples = NULL; // this array cleared with above call
 
            Logger::Instance()->AppendDebugMethod(
                "FFmpegWriter::write_audio_packets (Successfully completed 2nd resampling for Planar formats)",
                "nb_samples", nb_samples);
 
        } else {
            // Create a new array
            const auto buf_size = static_cast<size_t>(audio_input_position)
                * (av_get_bytes_per_sample(audio_codec_ctx->sample_fmt) /
                   av_get_bytes_per_sample(AV_SAMPLE_FMT_S16)
                );
            final_samples = reinterpret_cast<int16_t*>(
                    av_malloc(sizeof(int16_t) * buf_size));
 
            // Copy audio into buffer for frame
            memcpy(final_samples, samples,
                audio_input_position * av_get_bytes_per_sample(audio_codec_ctx->sample_fmt));
 
            // Init the nb_samples property
            frame_final->nb_samples = frame_nb_samples;
            frame_final->format = audio_codec_ctx->sample_fmt;
#if HAVE_CH_LAYOUT
            av_channel_layout_copy(&frame_final->ch_layout, &audio_codec_ctx->ch_layout);
#else
            frame_final->channels = audio_codec_ctx->channels;
            frame_final->channel_layout = audio_codec_ctx->channel_layout;
#endif
 
            // Fill the final_frame AVFrame with audio (non planar)
#if HAVE_CH_LAYOUT
            int nb_channels = audio_codec_ctx->ch_layout.nb_channels;
#else
            int nb_channels = audio_codec_ctx->channels;
#endif
            avcodec_fill_audio_frame(frame_final, nb_channels,
                audio_codec_ctx->sample_fmt, (uint8_t *) final_samples,
                audio_encoder_buffer_size, 0);
        }
 
        // Set the AVFrame's PTS
        frame_final->pts = audio_timestamp;
 
        // Init the packet
#if IS_FFMPEG_3_2
        AVPacket* pkt = av_packet_alloc();
#else
        AVPacket* pkt;
        av_init_packet(pkt);
        pkt->data = audio_encoder_buffer;
        pkt->size = audio_encoder_buffer_size;
#endif
 
        // Set the packet's PTS prior to encoding
        pkt->pts = pkt->dts = audio_timestamp;
 
        /* encode the audio samples */
        int got_packet_ptr = 0;
 
#if IS_FFMPEG_3_2
        // Encode audio (latest version of FFmpeg)
        int error_code;
        int ret = 0;
        int frame_finished = 0;
        error_code = ret =  avcodec_send_frame(audio_codec_ctx, frame_final);
        if (ret < 0 && ret !=  AVERROR(EINVAL) && ret != AVERROR_EOF
                && audio_codec_ctx->codec
                && (audio_codec_ctx->codec->capabilities & AV_CODEC_CAP_DELAY)) {
            avcodec_send_frame(audio_codec_ctx, NULL);
        }
        else {
            if (ret >= 0)
                pkt->size = 0;
            ret =  avcodec_receive_packet(audio_codec_ctx, pkt);
            if (ret >= 0)
                frame_finished = 1;
            if(ret == AVERROR(EINVAL) || ret == AVERROR_EOF) {
                ret = 0;
            }
            if (ret >= 0) {
                ret = frame_finished;
            }
        }
        if (!pkt->data && !frame_finished)
        {
            ret = -1;
        }
        got_packet_ptr = ret;
#else
        // Encode audio (older versions of FFmpeg)
        int error_code = avcodec_encode_audio2(audio_codec_ctx, pkt, frame_final, &got_packet_ptr);
#endif
        /* if zero size, it means the image was buffered */
        if (error_code == 0 && got_packet_ptr > 0) {
 
            // Delayed encoders (AAC) return timestamps for earlier input frames.
            // Preserve those timestamps, just as the flush path does.
            if (pkt->pts == AV_NOPTS_VALUE)
                pkt->pts = audio_timestamp;
            if (pkt->dts == AV_NOPTS_VALUE)
                pkt->dts = pkt->pts;
            if (pkt->duration <= 0) {
                pkt->duration = frame_nb_samples;
            }
 
            // Scale the PTS to the audio stream timebase (which is sometimes different than the codec's timebase)
            av_packet_rescale_ts(pkt, audio_codec_ctx->time_base, audio_st->time_base);
 
            // set stream
            pkt->stream_index = audio_st->index;
            pkt->flags |= AV_PKT_FLAG_KEY;
 
            /* write the compressed frame in the media file */
            error_code = av_interleaved_write_frame(oc, pkt);
        }
 
        if (error_code < 0) {
            Logger::Instance()->AppendDebugMethod(
                "FFmpegWriter::write_audio_packets ERROR ["
                    + av_err2string(error_code) + "]",
                "error_code", error_code);
        }
 
        // Count submitted samples per channel, including a partial final frame.
        audio_timestamp += frame_nb_samples;
 
        // deallocate AVFrame
        av_freep(&(frame_final->data[0]));
        AV_FREE_FRAME(&frame_final);
 
        // deallocate memory for packet
        AV_FREE_PACKET(pkt);
 
        // Reset position
        audio_input_position = 0;
        is_final = false;
    }
 
    // Delete arrays (if needed)
    if (all_resampled_samples) {
        av_freep(&all_resampled_samples);
        all_resampled_samples = NULL;
    }
    if (all_queued_samples) {
        av_freep(&all_queued_samples);
        all_queued_samples = NULL;
    }
}
 
// Allocate an AVFrame object
AVFrame *FFmpegWriter::allocate_avframe(PixelFormat pix_fmt, int width, int height, int *buffer_size, uint8_t *new_buffer) {
    // Create an RGB AVFrame
    AVFrame *new_av_frame = NULL;
 
    // Allocate an AVFrame structure
    new_av_frame = AV_ALLOCATE_FRAME();
    if (new_av_frame == NULL)
        throw OutOfMemory("Could not allocate AVFrame", path);
 
    // Determine required buffer size and allocate buffer
    *buffer_size = AV_GET_IMAGE_SIZE(pix_fmt, width, height);
 
    // Create buffer (if not provided)
    if (!new_buffer) {
        int palette_padding = 0;
#ifdef AV_PIX_FMT_FLAG_PSEUDOPAL
        // Old av_frame_ref/av_image_copy still read a synthetic RGB8 palette,
        // even though av_image_get_buffer_size excludes it. Keep it readable
        // when the encoder takes a reference to this externally owned buffer.
        if (av_pix_fmt_desc_get(pix_fmt)->flags & AV_PIX_FMT_FLAG_PSEUDOPAL)
            palette_padding = 1024;
#endif
        // New Buffer
        new_buffer = (uint8_t *) av_malloc(*buffer_size + palette_padding);
        if (!new_buffer)
            throw OutOfMemory("Could not allocate video frame buffer", path);
        if (palette_padding)
            memset(new_buffer + *buffer_size, 0, palette_padding);
        // Attach buffer to AVFrame
        AV_COPY_PICTURE_DATA(new_av_frame, new_buffer, pix_fmt, width, height);
        new_av_frame->width = width;
        new_av_frame->height = height;
        new_av_frame->format = pix_fmt;
    }
 
    // return AVFrame
    return new_av_frame;
}
 
// process video frame
void FFmpegWriter::process_video_packet(std::shared_ptr<Frame> frame) {
    // Source dimensions (RGBA)
    int src_w = frame->GetWidth();
    int src_h = frame->GetHeight();
 
    // Skip empty frames (1×1)
    if (src_w == 1 && src_h == 1)
        return;
 
    // Point persistent_src_frame->data to RGBA pixels
    const uchar* pixels = frame->GetPixels();
    if (!persistent_src_frame) {
        persistent_src_frame = av_frame_alloc();
        if (!persistent_src_frame)
            throw OutOfMemory("Could not allocate persistent_src_frame", path);
        persistent_src_frame->format      = AV_PIX_FMT_RGBA;
        persistent_src_frame->width       = src_w;
        persistent_src_frame->height      = src_h;
        persistent_src_frame->linesize[0] = src_w * 4;
    }
    persistent_src_frame->data[0] = const_cast<uint8_t*>(
        reinterpret_cast<const uint8_t*>(pixels)
    );
 
    // Prepare persistent_dst_frame + buffer on first use
    if (!persistent_dst_frame) {
        persistent_dst_frame = av_frame_alloc();
        if (!persistent_dst_frame)
            throw OutOfMemory("Could not allocate persistent_dst_frame", path);
 
        // Decide destination pixel format: NV12 if HW accel is on, else encoder’s pix_fmt
        AVPixelFormat dst_fmt = video_codec_ctx->pix_fmt;
#if USE_HW_ACCEL
        if (hw_en_on && hw_en_supported) {
            dst_fmt = AV_PIX_FMT_NV12;
        }
#endif
        persistent_dst_frame->format = dst_fmt;
        persistent_dst_frame->width  = info.width;
        persistent_dst_frame->height = info.height;
 
        persistent_dst_size = av_image_get_buffer_size(
            dst_fmt, info.width, info.height, 32
        );
        if (persistent_dst_size < 0)
            throw ErrorEncodingVideo("Invalid destination image size", -1);
 
        persistent_dst_buffer = static_cast<uint8_t*>(
            av_malloc(persistent_dst_size)
        );
        if (!persistent_dst_buffer)
            throw OutOfMemory("Could not allocate persistent_dst_buffer", path);
 
        av_image_fill_arrays(
            persistent_dst_frame->data,
            persistent_dst_frame->linesize,
            persistent_dst_buffer,
            dst_fmt,
            info.width,
            info.height,
            32
        );
    }
 
    // Initialize SwsContext (RGBA → dst_fmt) on first use
    if (!img_convert_ctx) {
        int flags = SWS_FAST_BILINEAR;
        if (openshot::Settings::Instance()->HIGH_QUALITY_SCALING) {
            flags = SWS_BICUBIC;
        }
        AVPixelFormat dst_fmt = video_codec_ctx->pix_fmt;
#if USE_HW_ACCEL
        if (hw_en_on && hw_en_supported) {
            dst_fmt = AV_PIX_FMT_NV12;
        }
#endif
        img_convert_ctx = sws_getContext(
            src_w, src_h, AV_PIX_FMT_RGBA,
            info.width, info.height, dst_fmt,
            flags, NULL, NULL, NULL
        );
        if (!img_convert_ctx)
            throw ErrorEncodingVideo("Could not initialize sws context", -1);
    }
 
    // Scale RGBA → dst_fmt into persistent_dst_buffer
    sws_scale(
        img_convert_ctx,
        persistent_src_frame->data,
        persistent_src_frame->linesize,
        0, src_h,
        persistent_dst_frame->data,
        persistent_dst_frame->linesize
    );
 
    // Allocate a new AVFrame + buffer, then copy scaled data into it
    int bytes_final = 0;
    AVPixelFormat dst_fmt = video_codec_ctx->pix_fmt;
#if USE_HW_ACCEL
    if (hw_en_on && hw_en_supported) {
        dst_fmt = AV_PIX_FMT_NV12;
    }
#endif
 
    AVFrame* new_frame = allocate_avframe(
        dst_fmt,
        info.width,
        info.height,
        &bytes_final,
        nullptr
    );
    if (!new_frame)
        throw OutOfMemory("Could not allocate new_frame via allocate_avframe", path);
 
    // Copy visible pixels from padded scaler planes into the packed encoder frame.
#ifdef AV_PIX_FMT_FLAG_PSEUDOPAL
    // Older FFmpeg's av_image_copy also copies a synthetic palette for RGB8
    // (GIF), although av_image_get_buffer_size no longer allocates that palette.
    if (av_pix_fmt_desc_get(dst_fmt)->flags & AV_PIX_FMT_FLAG_PSEUDOPAL) {
        av_image_copy_plane(new_frame->data[0], new_frame->linesize[0],
            persistent_dst_frame->data[0], persistent_dst_frame->linesize[0],
            av_image_get_linesize(dst_fmt, info.width, 0), info.height);
    } else
#endif
    av_image_copy(new_frame->data, new_frame->linesize,
        const_cast<const uint8_t**>(persistent_dst_frame->data),
        persistent_dst_frame->linesize, dst_fmt, info.width, info.height);
 
    // Queue the deep‐copied frame for encoding
    add_avframe(frame, new_frame);
}
 
// write video frame
bool FFmpegWriter::write_video_packet(std::shared_ptr<Frame> frame, AVFrame *frame_final) {
#if (LIBAVFORMAT_VERSION_MAJOR >= 58)
    // FFmpeg 4.0+
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::write_video_packet",
        "frame->number", frame->number,
        "oc->oformat->flags", oc->oformat->flags);
 
    if (AV_GET_CODEC_TYPE(video_st) == AVMEDIA_TYPE_VIDEO && AV_FIND_DECODER_CODEC_ID(video_st) == AV_CODEC_ID_RAWVIDEO) {
#else
    // TODO: Should we have moved away from oc->oformat->flags / AVFMT_RAWPICTURE
    // on ffmpeg < 4.0 as well?
    // Does AV_CODEC_ID_RAWVIDEO not work in ffmpeg 3.x?
    Logger::Instance()->AppendDebugMethod(
        "FFmpegWriter::write_video_packet",
        "frame->number", frame->number,
        "oc->oformat->flags & AVFMT_RAWPICTURE", oc->oformat->flags & AVFMT_RAWPICTURE);
 
    if (oc->oformat->flags & AVFMT_RAWPICTURE) {
#endif
        // The packet owns a separate, padded buffer. write_frame() still owns
        // frame_final, so handing its data to av_packet_from_data would free it twice.
        AVPacket packet = {};
        const PixelFormat format = static_cast<PixelFormat>(frame_final->format);
        const int size = AV_GET_IMAGE_SIZE(format, frame_final->width, frame_final->height);
        int error_code = size < 0 ? size : av_new_packet(&packet, size);
        if (error_code >= 0) {
            // Copy every plane, not just the first plane's stride * height.
            error_code = av_image_copy_to_buffer(packet.data, packet.size,
                frame_final->data, frame_final->linesize, format,
                frame_final->width, frame_final->height, 1);
        }
        if (error_code >= 0) {
            packet.flags |= AV_PKT_FLAG_KEY;
            packet.stream_index = video_st->index;
            packet.pts = packet.dts = video_timestamp;
            packet.duration = av_rescale_q(1, av_make_q(info.fps.den, info.fps.num), video_codec_ctx->time_base);
            av_packet_rescale_ts(&packet, video_codec_ctx->time_base, video_st->time_base);
            error_code = av_interleaved_write_frame(oc, &packet);
        }
        AV_FREE_PACKET(&packet);
        if (error_code < 0) {
            Logger::Instance()->AppendDebugMethod(
                "FFmpegWriter::write_video_packet ERROR ["
                    + av_err2string(error_code) + "]",
                "error_code", error_code);
            return false;
        }
    } else
    {
 
#if IS_FFMPEG_3_2
        AVPacket* pkt = av_packet_alloc();
#else
        AVPacket* pkt;
        av_init_packet(pkt);
#endif
        pkt->data = NULL;
        pkt->size = 0;
        pkt->pts = pkt->dts = AV_NOPTS_VALUE;
 
        // Assign the initial AVFrame PTS from the frame counter
        frame_final->pts = video_timestamp;
#if USE_HW_ACCEL
        if (hw_en_on && hw_en_supported) {
            if (!(hw_frame = av_frame_alloc())) {
                std::clog << "Error code: av_hwframe_alloc\n";
            }
            if (av_hwframe_get_buffer(video_codec_ctx->hw_frames_ctx, hw_frame, 0) < 0) {
                std::clog << "Error code: av_hwframe_get_buffer\n";
            }
            if (!hw_frame->hw_frames_ctx) {
                std::clog << "Error hw_frames_ctx.\n";
            }
            // Keep the hardware format assigned by av_hwframe_get_buffer().
            // NV12 describes the CPU source, not the encoder surface.
            if ( av_hwframe_transfer_data(hw_frame, frame_final, 0) < 0) {
                std::clog << "Error while transferring frame data to surface.\n";
            }
            av_frame_copy_props(hw_frame, frame_final);
        }
#endif // USE_HW_ACCEL
        /* encode the image */
        int got_packet_ptr = 0;
        int error_code = 0;
#if IS_FFMPEG_3_2
        // Write video packet
        int ret;
 
    #if USE_HW_ACCEL
        if (hw_en_on && hw_en_supported) {
            ret = avcodec_send_frame(video_codec_ctx, hw_frame);  //hw_frame!!!
        } else
    #endif // USE_HW_ACCEL
        {
            ret = avcodec_send_frame(video_codec_ctx, frame_final);
        }
        error_code = ret;
        if (ret < 0 ) {
            Logger::Instance()->AppendDebugMethod(
                "FFmpegWriter::write_video_packet (Frame not sent)");
            if (ret == AVERROR(EAGAIN) ) {
                std::clog << "Frame EAGAIN\n";
            }
            if (ret == AVERROR_EOF ) {
                std::clog << "Frame AVERROR_EOF\n";
            }
            avcodec_send_frame(video_codec_ctx, NULL);
        }
        else {
            while (ret >= 0) {
                ret = avcodec_receive_packet(video_codec_ctx, pkt);
 
                if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
                    got_packet_ptr = 0;
                    break;
                }
                if (ret == 0) {
                    got_packet_ptr = 1;
                    break;
                }
            }
        }
#else
        // Write video packet (older than FFmpeg 3.2)
        error_code = avcodec_encode_video2(video_codec_ctx, pkt, frame_final, &got_packet_ptr);
        if (error_code != 0) {
            Logger::Instance()->AppendDebugMethod(
                "FFmpegWriter::write_video_packet ERROR ["
                    + av_err2string(error_code) + "]",
                "error_code", error_code);
        }
        if (got_packet_ptr == 0) {
            Logger::Instance()->AppendDebugMethod(
                "FFmpegWriter::write_video_packet (Frame gotpacket error)");
        }
#endif // IS_FFMPEG_3_2
 
        /* if zero size, it means the image was buffered */
        if (error_code == 0 && got_packet_ptr) {
            // set the timestamp
            if (pkt->duration <= 0) {
                pkt->duration = av_rescale_q(1, av_make_q(info.fps.den, info.fps.num), video_codec_ctx->time_base);
            }
            av_packet_rescale_ts(pkt, video_codec_ctx->time_base, video_st->time_base);
            pkt->stream_index = video_st->index;
 
            /* write the compressed frame in the media file */
            int result = av_interleaved_write_frame(oc, pkt);
            if (result < 0) {
                Logger::Instance()->AppendDebugMethod(
                    "FFmpegWriter::write_video_packet ERROR ["
                        + av_err2string(result) + "]",
                    "result", result);
                return false;
            }
        }
 
        // Deallocate packet
        AV_FREE_PACKET(pkt);
#if USE_HW_ACCEL
        if (hw_en_on && hw_en_supported) {
            if (hw_frame) {
                av_frame_free(&hw_frame);
                hw_frame = NULL;
            }
        }
#endif // USE_HW_ACCEL
    }
 
    // Increment PTS (in frames and scaled to the codec's timebase)
    video_timestamp += av_rescale_q(1, av_make_q(info.fps.den, info.fps.num), video_codec_ctx->time_base);
 
    // Success
    return true;
}
 
// Output the ffmpeg info about this format, streams, and codecs (i.e. dump format)
void FFmpegWriter::OutputStreamInfo() {
    // output debug info
    av_dump_format(oc, 0, path.c_str(), 1);
}
 
// Set audio resample options
void FFmpegWriter::ResampleAudio(int sample_rate, int channels) {
    original_sample_rate = sample_rate;
    original_channels = channels;
}
 
// In FFmpegWriter.cpp
void FFmpegWriter::AddSphericalMetadata(const std::string& projection, float yaw_deg, float pitch_deg, float roll_deg) {
    if (!oc) return;
    if (!info.has_video || !video_st) return;
 
    // Allow movenc.c to write out the sv3d atom
    oc->strict_std_compliance = FF_COMPLIANCE_UNOFFICIAL;
 
#if LIBAVFORMAT_VERSION_INT >= AV_VERSION_INT(57, 0, 0)
    // Map the projection name to the enum (defaults to equirectangular)
    int proj = av_spherical_from_name(projection.c_str());
    if (proj < 0)
        proj = AV_SPHERICAL_EQUIRECTANGULAR;
 
    // Allocate the side‐data structure
    size_t sd_size = 0;
    AVSphericalMapping* map = av_spherical_alloc(&sd_size);
    if (!map) return;
 
    // Populate it
    map->projection = static_cast<AVSphericalProjection>(proj);
    // yaw/pitch/roll are 16.16 fixed point
    map->yaw   = static_cast<int32_t>(yaw_deg   * (1 << 16));
    map->pitch = static_cast<int32_t>(pitch_deg * (1 << 16));
    map->roll  = static_cast<int32_t>(roll_deg  * (1 << 16));
 
#if LIBAVFORMAT_VERSION_MAJOR >= 61
    // Encoder initialization copies coded side data into the stream parameters.
    // Keep the mapping on the context so that copy does not discard it.
    AVPacketSideData* side_data = av_packet_side_data_add(
        &video_codec_ctx->coded_side_data, &video_codec_ctx->nb_coded_side_data,
        AV_PKT_DATA_SPHERICAL, reinterpret_cast<uint8_t*>(map), sd_size, 0);
    if (!side_data)
        av_free(map);
#else
    if (ffmpeg_stream_add_side_data(video_st, AV_PKT_DATA_SPHERICAL,
            reinterpret_cast<uint8_t*>(map), sd_size) < 0)
        av_free(map);
#endif
#endif
}