as I'm fairly new to FFMpeg Programming and C in general, the code looks like a mess.
I have smashed my head against a wall trying to get this code to work for about a week.
int decode_encode_pipeline(AVFormatContext *Input_Format_Context, AVFormatContext *Output_Format_Context, int *streams_list){
const AVCodec *DECodec, *ENCodec;
AVCodecContext *DECodecContext = NULL, *ENCodecContext = NULL;
AVCodecParameters *CodecParameters = NULL;
AVDictionary *opts = NULL;
AVPacket *Packet;
AVFrame *Frame;
int check;
Packet = av_packet_alloc();
if(!Packet){
printf("\nFehler bei Allocating Packet");
return 0;
}
Frame = av_frame_alloc();
if(!Frame){
printf("\nFehler bei Allocating Frame");
return 0;
}
CodecParameters = Input_Format_Context->streams[Packet->stream_index]->codecpar;
if(!CodecParameters){
printf("\nCodecParameters konnte nicht erstellt oder zugewiesen werden.");
}
DECodec = avcodec_find_decoder(CodecParameters->codec_id);
if(!DECodec){
printf("\nCodec nicht gefunden");
return 0;
}
DECodecContext = avcodec_alloc_context3(DECodec);
if (!DECodecContext){
printf("\nFehler bei Allocating CodecContext");
return 0;
}
ENCodec = avcodec_find_encoder(CodecParameters->codec_id);
if(!DECodec){
printf("\nCodec nicht gefunden");
return 0;
}
ENCodecContext = avcodec_alloc_context3(ENCodec);
if (!ENCodecContext){
printf("\nFehler bei Allocating CodecContext");
return 0;
}
check = avformat_write_header(Output_Format_Context, &opts);
if(check < 0){
printf("\nFehler beim Öffnen des Output Files.");
return 1;
}
avcodec_parameters_to_context(DECodecContext, CodecParameters);
avcodec_parameters_to_context(ENCodecContext, CodecParameters);
ENCodecContext->width = DECodecContext->width;
ENCodecContext->height = DECodecContext->height;
ENCodecContext->bit_rate = DECodecContext->bit_rate;
ENCodecContext->time_base = (AVRational){1, 30};
ENCodecContext->framerate = DECodecContext->framerate;
ENCodecContext->gop_size = DECodecContext->gop_size;
ENCodecContext->max_b_frames = DECodecContext->max_b_frames;
ENCodecContext->pix_fmt = DECodecContext->pix_fmt;
if(ENCodec->id == AV_CODEC_ID_H264){
av_opt_set(ENCodecContext->priv_data, "preset", "slow", 0);
}
check = avcodec_open2(DECodecContext, DECodec, NULL);
if(check < 0){
printf("\nFehler bei Öffnen von DECodec");
return 1;
}
check = avcodec_open2(ENCodecContext, ENCodec, NULL);
if(check < 0){
printf("\nFehler bei Öffnen von ENCodec");
return 1;
}
while(1){
check = av_read_frame(Input_Format_Context, Packet);
if(check < 0){
break;
}
AVStream *in_stream, *out_stream;
in_stream = Input_Format_Context->streams[Packet->stream_index];
out_stream = Output_Format_Context->streams[Packet->stream_index];
if(in_stream->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && Packet->stream_index == streams_list[Packet->stream_index]){
check = avcodec_send_packet(DECodecContext, Packet);
if(check < 0){
printf("\nFehler bei Encoding");
return 1;
}
AVPacket *EncodedPacket;
EncodedPacket = av_packet_alloc();
if(!EncodedPacket){
printf("\nFehler bei Allocating Packet");
return 1;
}
/*While Loop Decoding*/
while(check >= 0){
check = avcodec_receive_frame(DECodecContext, Frame);
if(check == AVERROR(EAGAIN)){
continue;
}else if(check == AVERROR_EOF){
break;
}else if(check < 0){
printf("\nFehler bei Decoding");
return 1;
}
/*Convert Colorspace*/
struct SwsContext *SwsContexttoRGB = sws_getContext(Frame->width, Frame->height, Frame->format, Frame->width, Frame->height, AV_PIX_FMT_RGB24, SWS_BILINEAR, NULL, NULL, NULL);
struct SwsContext *SwsContexttoOriginal = sws_getContext(Frame->width, Frame->height, AV_PIX_FMT_RGB24, Frame->width, Frame->height, Frame->format, SWS_BILINEAR, NULL, NULL, NULL);
if(!SwsContexttoRGB || !SwsContexttoOriginal){
printf("\nSwsContext konnte nicht befüllt werden.");
return 1;
}
if(Frame->linesize < 0){
printf("\nFehler: linesize ist negativ und nicht kompatibel\n");
return 1;
}
AVFrame *RGBFrame;
RGBFrame = av_frame_alloc();
if(!RGBFrame){
printf("\nFehler bei der Reservierung für den RGBFrame");
return 1;
}
/*
int number_bytes = av_image_get_buffer_size(AV_PIX_FMT_RGB24, Frame->width, Frame->height, 1);
if(number_bytes < 0){
printf("\nFehler bei der Berechnung der benoetigten Bytes fuer Konvertierung");
return 1;
}
uint8_t *rgb_buffer = (uint8_t *)av_malloc(number_bytes*sizeof(uint8_t));
if(rgb_buffer == NULL){
printf("\nFehler bei der Reservierung für den RGBBuffer");
return 1;
}
check = av_image_fill_arrays(RGBFrame->data, RGBFrame->linesize, rgb_buffer, AV_PIX_FMT_RGB24, Frame->width, Frame->height, 1);
if(check < 0){
printf("\nFehler bei der Zuweisung der RGB Daten");
return 1;
}*/
//sws_scale(SwsContexttoRGB, (const uint8_t * const *)Frame->data, Frame->linesize, 0, Frame->height, RGBFrame->data, RGBFrame->linesize);
sws_scale_frame(SwsContexttoRGB, Frame, RGBFrame);
printf("\nIch habe die Daten zu RGB konvertiert.");
//sws_scale(SwsContexttoOriginal, (const uint8_t * const *)RGBFrame->data, RGBFrame->linesize, 0, Frame->height, Frame->data, Frame->linesize);
sws_scale_frame(SwsContexttoOriginal, RGBFrame, Frame);
printf("\nIch habe die Daten zurück ins Original konvertiert.");
Frame->format = ENCodecContext->pix_fmt;
Frame->width = ENCodecContext->width;
Frame->height = ENCodecContext->height;
check = av_frame_get_buffer(Frame, 0);
if(check < 0){
printf("\nFehler bei Allocating Frame Buffer");
return 1;
}
/* Encoding */
check = av_frame_make_writable(Frame);
if(check < 0){
printf("\nFehler bei Make Frame Writable");
return 1;
}
encode(ENCodecContext, Frame, EncodedPacket, Output_Format_Context);
sws_freeContext(SwsContexttoRGB);
sws_freeContext(SwsContexttoOriginal);
av_frame_free(&RGBFrame);
//av_free(rgb_buffer);
}
/* Flushing Encoder */
encode(ENCodecContext, NULL, EncodedPacket, Output_Format_Context);
//avcodec_flush_buffers(DECodecContext);
//avcodec_flush_buffers(ENCodecContext);
av_packet_free(&EncodedPacket);
}else{
av_interleaved_write_frame(Output_Format_Context, Packet);
}
}
av_write_trailer(Output_Format_Context);
/* Memory Free */
avcodec_free_context(&DECodecContext);
avcodec_free_context(&ENCodecContext);
avcodec_parameters_free(&CodecParameters);
av_frame_free(&Frame);
av_packet_free(&Packet);
return 0;
}
The function encode looks as follows:
static void encode(AVCodecContext *ENCodecContext, AVFrame *Frame, AVPacket *EncodedPacket, AVFormatContext *Output_Format_Context){
int check;
check = avcodec_send_frame(ENCodecContext, Frame);
if(check == AVERROR(EAGAIN)){
printf("\nEAGAIN");
}
if(check == AVERROR_EOF){
printf("\nEOF");
}
if(check == AVERROR(EINVAL)){
printf("\nEINVAL");
}
if(check == AVERROR(ENOMEM)){
printf("\nENOMEM");
}
if(check < 0){
printf("\nFehler bei Encoding Send Frame. Check = %d", check);
return;
}
while(check >= 0){
check = avcodec_receive_packet(ENCodecContext, EncodedPacket);
if(check == AVERROR(EAGAIN) || check == AVERROR_EOF){
return;
}else if(check < 0){
printf("\nFehler bei Encoding");
return;
}
if (av_interleaved_write_frame(Output_Format_Context, EncodedPacket) < 0) {
printf("\nFehler beim Muxen des Paketes.");
break;
}
av_packet_unref(EncodedPacket);
}
return;
}
The program should decode a video into the individual frames convert them to RGB24, so I can work with the raw data of the frame, then convert it back to the original format and encode the frames.
The encoder doesn't play nice, as I get an EOF error at avcodec_send_frame(). But I couldn't figure it out why the encoder behaves like this. And yes I have read the docs and example files, but either I'm massivly missing a crucial detail or I'm just ****.
Any and all help will be and is massivly appreciated.
PS.: The used libraries are libavutil, libavformat, libavcodec, libswscale. All installed with the "-dev" suffix through linux commandline. Should all be the version 7.0 libraries.
Thanks in advance. With best regards.
- Read the docs
- Shifting the encoding step out of the decoding while loop