#include <libavcodec/avcodec.h>

#include <libavformat/avformat.h>

#include <libavutil/timestamp.h>

#include <stdio.h>

#include <stdarg.h>

#include <stdlib.h>

#include <libavutil/opt.h>

#include <string.h>

#include <inttypes.h>

#include "video_debugging.h"

typedef struct StreamingParams {

char copy_video;

char copy_audio;

char *output_extension;

char *muxer_opt_key;

char *muxer_opt_value;

char *video_codec;

char *audio_codec;

char *codec_priv_key;

char *codec_priv_value;

} StreamingParams;

typedef struct StreamingContext {

AVFormatContext *avfc;

AVCodec *video_avc;

AVCodec *audio_avc;

AVStream *video_avs;

AVStream *audio_avs;

AVCodecContext *video_avcc;

AVCodecContext *audio_avcc;

int video_index;

int audio_index;

char *filename;

} StreamingContext;

int fill_stream_info(AVStream *avs, AVCodec **avc, AVCodecContext **avcc) {

*avc = avcodec_find_decoder(avs->codecpar->codec_id);

if (!*avc) {logging("failed to find the codec"); return -1;}

*avcc = avcodec_alloc_context3(*avc);

if (!*avcc) {logging("failed to alloc memory for codec context"); return -1;}

if (avcodec_parameters_to_context(*avcc, avs->codecpar) < 0) {logging("failed to fill codec context"); return -1;}

if (avcodec_open2(*avcc, *avc, NULL) < 0) {logging("failed to open codec"); return -1;}

return 0;

}

int open_media(const char *in_filename, AVFormatContext **avfc) {

*avfc = avformat_alloc_context();

if (!*avfc) {logging("failed to alloc memory for format"); return -1;}

if (avformat_open_input(avfc, in_filename, NULL, NULL) != 0) {logging("failed to open input file %s", in_filename); return -1;}

if (avformat_find_stream_info(*avfc, NULL) < 0) {logging("failed to get stream info"); return -1;}

return 0;

}

int prepare_decoder(StreamingContext *sc) {

for (int i = 0; i < sc->avfc->nb_streams; i++) {

if (sc->avfc->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {

sc->video_avs = sc->avfc->streams[i];

sc->video_index = i;

if (fill_stream_info(sc->video_avs, &sc->video_avc, &sc->video_avcc)) {return -1;}

} else if (sc->avfc->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {

sc->audio_avs = sc->avfc->streams[i];

sc->audio_index = i;

if (fill_stream_info(sc->audio_avs, &sc->audio_avc, &sc->audio_avcc)) {return -1;}

} else {

logging("skipping streams other than audio and video");

}

}

return 0;

}

int prepare_video_encoder(StreamingContext *sc, AVCodecContext *decoder_ctx, AVRational input_framerate, StreamingParams sp) {

sc->video_avs = avformat_new_stream(sc->avfc, NULL);

sc->video_avc = avcodec_find_encoder_by_name(sp.video_codec);

if (!sc->video_avc) {logging("could not find the proper codec"); return -1;}

sc->video_avcc = avcodec_alloc_context3(sc->video_avc);

if (!sc->video_avcc) {logging("could not allocated memory for codec context"); return -1;}

av_opt_set(sc->video_avcc->priv_data, "preset", "fast", 0);

if (sp.codec_priv_key && sp.codec_priv_value)

av_opt_set(sc->video_avcc->priv_data, sp.codec_priv_key, sp.codec_priv_value, 0);

sc->video_avcc->height = decoder_ctx->height;

sc->video_avcc->width = decoder_ctx->width;

sc->video_avcc->sample_aspect_ratio = decoder_ctx->sample_aspect_ratio;

if (sc->video_avc->pix_fmts)

sc->video_avcc->pix_fmt = sc->video_avc->pix_fmts[0];

else

sc->video_avcc->pix_fmt = decoder_ctx->pix_fmt;

sc->video_avcc->bit_rate = 2 * 1000 * 1000;

sc->video_avcc->rc_buffer_size = 4 * 1000 * 1000;

sc->video_avcc->rc_max_rate = 2 * 1000 * 1000;

sc->video_avcc->rc_min_rate = 2.5 * 1000 * 1000;

sc->video_avcc->time_base = av_inv_q(input_framerate);

sc->video_avs->time_base = sc->video_avcc->time_base;

if (avcodec_open2(sc->video_avcc, sc->video_avc, NULL) < 0) {logging("could not open the codec"); return -1;}

avcodec_parameters_from_context(sc->video_avs->codecpar, sc->video_avcc);

return 0;

}

int prepare_audio_encoder(StreamingContext *sc, int sample_rate, StreamingParams sp){

sc->audio_avs = avformat_new_stream(sc->avfc, NULL);

sc->audio_avc = avcodec_find_encoder_by_name(sp.audio_codec);

if (!sc->audio_avc) {logging("could not find the proper codec"); return -1;}

sc->audio_avcc = avcodec_alloc_context3(sc->audio_avc);

if (!sc->audio_avcc) {logging("could not allocated memory for codec context"); return -1;}

int OUTPUT_CHANNELS = 2;

int OUTPUT_BIT_RATE = 196000;

sc->audio_avcc->channels = OUTPUT_CHANNELS;

sc->audio_avcc->channel_layout = av_get_default_channel_layout(OUTPUT_CHANNELS);

sc->audio_avcc->sample_rate = sample_rate;

sc->audio_avcc->sample_fmt = sc->audio_avc->sample_fmts[0];

sc->audio_avcc->bit_rate = OUTPUT_BIT_RATE;

sc->audio_avcc->time_base = (AVRational){1, sample_rate};

sc->audio_avcc->strict_std_compliance = FF_COMPLIANCE_EXPERIMENTAL;

sc->audio_avs->time_base = sc->audio_avcc->time_base;

if (avcodec_open2(sc->audio_avcc, sc->audio_avc, NULL) < 0) {logging("could not open the codec"); return -1;}

avcodec_parameters_from_context(sc->audio_avs->codecpar, sc->audio_avcc);

return 0;

}

int prepare_copy(AVFormatContext *avfc, AVStream **avs, AVCodecParameters *decoder_par) {

*avs = avformat_new_stream(avfc, NULL);

avcodec_parameters_copy((*avs)->codecpar, decoder_par);

return 0;

}

int remux(AVPacket **pkt, AVFormatContext **avfc, AVRational decoder_tb, AVRational encoder_tb) {

av_packet_rescale_ts(*pkt, decoder_tb, encoder_tb);

if (av_interleaved_write_frame(*avfc, *pkt) < 0) { logging("error while copying stream packet"); return -1; }

return 0;

}

int encode_video(StreamingContext *decoder, StreamingContext *encoder, AVFrame *input_frame) {

if (input_frame) input_frame->pict_type = AV_PICTURE_TYPE_NONE;

AVPacket *output_packet = av_packet_alloc();

if (!output_packet) {logging("could not allocate memory for output packet"); return -1;}

int response = avcodec_send_frame(encoder->video_avcc, input_frame);

while (response >= 0) {

response = avcodec_receive_packet(encoder->video_avcc, output_packet);

if (response == AVERROR(EAGAIN) || response == AVERROR_EOF) {

break;

} else if (response < 0) {

logging("Error while receiving packet from encoder: %s", av_err2str(response));

return -1;

}

output_packet->stream_index = decoder->video_index;

output_packet->duration = encoder->video_avs->time_base.den / encoder->video_avs->time_base.num / decoder->video_avs->avg_frame_rate.num * decoder->video_avs->avg_frame_rate.den;

av_packet_rescale_ts(output_packet, decoder->video_avs->time_base, encoder->video_avs->time_base);

response = av_interleaved_write_frame(encoder->avfc, output_packet);

if (response != 0) { logging("Error %d while receiving packet from decoder: %s", response, av_err2str(response)); return -1;}

}

av_packet_unref(output_packet);

av_packet_free(&output_packet);

return 0;

}

int encode_audio(StreamingContext *decoder, StreamingContext *encoder, AVFrame *input_frame) {

AVPacket *output_packet = av_packet_alloc();

if (!output_packet) {logging("could not allocate memory for output packet"); return -1;}

int response = avcodec_send_frame(encoder->audio_avcc, input_frame);

while (response >= 0) {

response = avcodec_receive_packet(encoder->audio_avcc, output_packet);

if (response == AVERROR(EAGAIN) || response == AVERROR_EOF) {

break;

} else if (response < 0) {

logging("Error while receiving packet from encoder: %s", av_err2str(response));

return -1;

}

output_packet->stream_index = decoder->audio_index;

av_packet_rescale_ts(output_packet, decoder->audio_avs->time_base, encoder->audio_avs->time_base);

response = av_interleaved_write_frame(encoder->avfc, output_packet);

if (response != 0) { logging("Error %d while receiving packet from decoder: %s", response, av_err2str(response)); return -1;}

}

av_packet_unref(output_packet);

av_packet_free(&output_packet);

return 0;

}

int transcode_audio(StreamingContext *decoder, StreamingContext *encoder, AVPacket *input_packet, AVFrame *input_frame) {

int response = avcodec_send_packet(decoder->audio_avcc, input_packet);

if (response < 0) {logging("Error while sending packet to decoder: %s", av_err2str(response)); return response;}

while (response >= 0) {

response = avcodec_receive_frame(decoder->audio_avcc, input_frame);

if (response == AVERROR(EAGAIN) || response == AVERROR_EOF) {

break;

} else if (response < 0) {

logging("Error while receiving frame from decoder: %s", av_err2str(response));

return response;

}

if (response >= 0) {

if (encode_audio(decoder, encoder, input_frame)) return -1;

}

av_frame_unref(input_frame);

}

return 0;

}

int transcode_video(StreamingContext *decoder, StreamingContext *encoder, AVPacket *input_packet, AVFrame *input_frame) {

int response = avcodec_send_packet(decoder->video_avcc, input_packet);

if (response < 0) {logging("Error while sending packet to decoder: %s", av_err2str(response)); return response;}

while (response >= 0) {

response = avcodec_receive_frame(decoder->video_avcc, input_frame);

if (response == AVERROR(EAGAIN) || response == AVERROR_EOF) {

break;

} else if (response < 0) {

logging("Error while receiving frame from decoder: %s", av_err2str(response));

return response;

}

if (response >= 0) {

if (encode_video(decoder, encoder, input_frame)) return -1;

}

av_frame_unref(input_frame);

}

return 0;

}

int main(int argc, char *argv[])

{

/*

* H264 -> H265

* Audio -> remuxed (untouched)

* MP4 - MP4

*/

StreamingParams sp = {0};

sp.copy_audio = 1;

sp.copy_video = 0;

sp.video_codec = "libx265";

sp.codec_priv_key = "x265-params";

sp.codec_priv_value = "keyint=60:min-keyint=60:scenecut=0";

/*

* H264 -> H264 (fixed gop)

* Audio -> remuxed (untouched)

* MP4 - MP4

*/

//StreamingParams sp = {0};

//sp.copy_audio = 1;

//sp.copy_video = 0;

//sp.video_codec = "libx264";

//sp.codec_priv_key = "x264-params";

//sp.codec_priv_value = "keyint=60:min-keyint=60:scenecut=0:force-cfr=1";

/*

* H264 -> H264 (fixed gop)

* Audio -> remuxed (untouched)

* MP4 - fragmented MP4

*/

//StreamingParams sp = {0};

//sp.copy_audio = 1;

//sp.copy_video = 0;

//sp.video_codec = "libx264";

//sp.codec_priv_key = "x264-params";

//sp.codec_priv_value = "keyint=60:min-keyint=60:scenecut=0:force-cfr=1";

//sp.muxer_opt_key = "movflags";

//sp.muxer_opt_value = "frag_keyframe+empty_moov+delay_moov+default_base_moof";

/*

* H264 -> H264 (fixed gop)

* Audio -> AAC

* MP4 - MPEG-TS

*/

//StreamingParams sp = {0};

//sp.copy_audio = 0;

//sp.copy_video = 0;

//sp.video_codec = "libx264";

//sp.codec_priv_key = "x264-params";

//sp.codec_priv_value = "keyint=60:min-keyint=60:scenecut=0:force-cfr=1";

//sp.audio_codec = "aac";

//sp.output_extension = ".ts";

/*

* H264 -> VP9

* Audio -> Vorbis

* MP4 - WebM

*/

//StreamingParams sp = {0};

//sp.copy_audio = 0;

//sp.copy_video = 0;

//sp.video_codec = "libvpx-vp9";

//sp.audio_codec = "libvorbis";

//sp.output_extension = ".webm";

StreamingContext *decoder = (StreamingContext*) calloc(1, sizeof(StreamingContext));

decoder->filename = argv[1];

StreamingContext *encoder = (StreamingContext*) calloc(1, sizeof(StreamingContext));

encoder->filename = argv[2];

if (sp.output_extension)

strcat(encoder->filename, sp.output_extension);

if (open_media(decoder->filename, &decoder->avfc)) return -1;

if (prepare_decoder(decoder)) return -1;

avformat_alloc_output_context2(&encoder->avfc, NULL, NULL, encoder->filename);

if (!encoder->avfc) {logging("could not allocate memory for output format");return -1;}

for (int i = 0; i < decoder->avfc->nb_streams; i++) {

if (decoder->avfc->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO)

{

if (!sp.copy_video) {

AVRational input_framerate = av_guess_frame_rate(decoder->avfc, decoder->video_avs, NULL);

prepare_video_encoder(encoder, decoder->video_avcc, input_framerate, sp);

} else {

if (prepare_copy(encoder->avfc, &encoder->video_avs, decoder->video_avs->codecpar)) {return -1;}

}

}

if (decoder->avfc->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO)

{

if (!sp.copy_audio) {

if (prepare_audio_encoder(encoder, decoder->audio_avcc->sample_rate, sp)) {return -1;}

} else {

if (prepare_copy(encoder->avfc, &encoder->audio_avs, decoder->audio_avs->codecpar)) {return -1;}

}

}

}

if (encoder->avfc->oformat->flags & AVFMT_GLOBALHEADER)

encoder->avfc->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;

if (!(encoder->avfc->oformat->flags & AVFMT_NOFILE)) {

if (avio_open(&encoder->avfc->pb, encoder->filename, AVIO_FLAG_WRITE) < 0) {

logging("could not open the output file");

return -1;

}

}

AVDictionary* muxer_opts = NULL;

if (sp.muxer_opt_key && sp.muxer_opt_value) {

av_dict_set(&muxer_opts, sp.muxer_opt_key, sp.muxer_opt_value, 0);

}

if (avformat_write_header(encoder->avfc, &muxer_opts) < 0) {logging("an error occurred when opening output file"); return -1;}

AVFrame *input_frame = av_frame_alloc();

if (!input_frame) {logging("failed to allocated memory for AVFrame"); return -1;}

AVPacket *input_packet = av_packet_alloc();

if (!input_packet) {logging("failed to allocated memory for AVPacket"); return -1;}

while (av_read_frame(decoder->avfc, input_packet) >= 0)

{

if (decoder->avfc->streams[input_packet->stream_index]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {

if (!sp.copy_video) {

// TODO: refactor to be generic for audio and video (receiving a function pointer to the differences)

if (transcode_video(decoder, encoder, input_packet, input_frame)) return -1;

av_packet_unref(input_packet);

} else {

if (remux(&input_packet, &encoder->avfc, decoder->video_avs->time_base, encoder->video_avs->time_base)) return -1;

}

} else if (decoder->avfc->streams[input_packet->stream_index]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {

if (!sp.copy_audio) {

if (transcode_audio(decoder, encoder, input_packet, input_frame)) return -1;

av_packet_unref(input_packet);

} else {

if (remux(&input_packet, &encoder->avfc, decoder->audio_avs->time_base, encoder->audio_avs->time_base)) return -1;

}

} else {

logging("ignoring all non video or audio packets");

}

}

if (!sp.copy_video)

if (encode_video(decoder, encoder, NULL)) return -1;

if (!sp.copy_audio)

if (encode_audio(decoder, encoder, NULL)) return -1;

av_write_trailer(encoder->avfc);

if (muxer_opts != NULL) {

av_dict_free(&muxer_opts);

muxer_opts = NULL;

}

if (input_frame != NULL) {

av_frame_free(&input_frame);

input_frame = NULL;

}

if (input_packet != NULL) {

av_packet_free(&input_packet);

input_packet = NULL;

}

avformat_close_input(&decoder->avfc);

avformat_free_context(decoder->avfc); decoder->avfc = NULL;

avformat_free_context(encoder->avfc); encoder->avfc = NULL;

avcodec_free_context(&decoder->video_avcc); decoder->video_avcc = NULL;

avcodec_free_context(&decoder->audio_avcc); decoder->audio_avcc = NULL;

free(decoder); decoder = NULL;

free(encoder); encoder = NULL;

return 0;

}