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• Decoding audio with FFMPEG

  8 juillet 2012, par Mariano

  I am using FFMPEG to decode an audio file, but I am not able to do it.

      AVFormatContext *pFormatCtx;
  
  AVCodec *pCodec_audio;
  
  AVCodecContext *aCodecCtx_audio = NULL;
  
  AVPacket packet;
  
  string outfilename = "salida.avi";
  
  string filename = "john.wav";
  
  int audioStream;
  
  int out_size, len, size;
  
  FILE *outfile;
  
  int16_t *outbuf;
  
  uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];
  
  avcodec_init();
  
  /* register all the codecs */
  
  av_register_all();
  
  
  
  if(av_open_input_file(&pFormatCtx, filename.c_str(), NULL, 0, NULL) != 0) {
  
      cerr << "Archivo no encontrado" << endl;
  
      return -1; // Couldn't open file
  
  }
  
  
  
  if(av_find_stream_info(pFormatCtx) < 0) {
  
      cerr << " No encontro el stream de info" << endl;
  
      return -1;// Couldn't find stream information
  
  }
  
  
  
  dump_format(pFormatCtx, 0, filename.c_str(), 0);
  
  
  
  for(unsigned int i=0; i < pFormatCtx->nb_streams; i++)
  
    if(pFormatCtx->streams[i]->codec->codec_type == CODEC_TYPE_AUDIO)
  
        audioStream = i;
  
  aCodecCtx_audio = pFormatCtx->streams[audioStream]->codec;
  
  pCodec_audio = avcodec_find_decoder(aCodecCtx_audio->codec_id);
  
  if(pCodec_audio == NULL) {
  
      cerr<< "Unsupported codec!" << endl;
  
      return -1; // Codec not found
  
  }
  
  
  
  if(avcodec_open(aCodecCtx_audio, pCodec_audio) < 0) {
  
      cerr << "No se pudo abrir el codec de audio" << endl;
  
      return -1;
  
  }
  
  
  
  outbuf = (int16_t*) av_malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
  
  
  
  outfile = fopen(outfilename.c_str(), "wb");
  
  if (!outfile) {
  
      exit(1);
  
  }
  
  
  
  av_init_packet(&packet);
  
  packet.data = inbuf;
  
  while(av_read_frame(pFormatCtx, &packet) == 0) {
  
      if(packet.stream_index == audioStream) {
  
          size = packet.size;
  
          if (size == 0) {
  
              cerr << "Size = 0 " << endl;
  
              break;
  
          }
  
          while(size > 0) {
  
              out_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
  
              len = avcodec_decode_audio3(aCodecCtx_audio, outbuf, &out_size , &packet);
  
              //av_free_packet(&packet);
  
              cout << len << endl;
  
              if(len == -1) {
  
                  cerr << "Error while decoding" << endl;
  
                  return 1;
  
              }
  
              if(out_size > 0) {
  
                  fwrite(outbuf, 1, out_size, outfile);
  
              }
  
              size -= len;
  
              packet.data += len;
  
          }
  
      }
  
  }
  
  av_free_packet(&packet);
  
  
  
  
  
  fclose(outfile);
  
  free(outbuf);
  
  cout << "END CODE" << endl;
  
  avcodec_close(aCodecCtx_audio);
  
  av_free(aCodecCtx_audio);

  In the code I am trying to decode an .wav file to a .avi file. The output file ("salida.avi") is created , but does not play.

• avfilter/vf_libplacebo : don't force dovi frames to bt.2020-ncl

  30 octobre 2023, par Niklas Haas

  avfilter/vf_libplacebo : don't force dovi frames to bt.2020-ncl
  This is at odds with the YUV matrix negotiation API, in which such
  
  dynamic changes in YUV encoding are no longer easily possible. There is
  
  also no really strong motivating reason to do this, since the choice of
  
  YUV matrix is essentially arbitrary and not actually related to the
  
  Dolby Vision decoding process.
  

  • [DH] libavfilter/vf_libplacebo.c

• avcodec/evc : Reference to ISO_IEC_23094-1-2020 document section for EVC_MAX_APS_COUNT...

  18 avril 2024, par Dawid Kozinski

  avcodec/evc : Reference to ISO_IEC_23094-1-2020 document section for EVC_MAX_APS_COUNT enum has been fixed
  Signed-off-by : Dawid Kozinski <d.kozinski@samsung.com>
  

  • [DH] libavcodec/evc.h