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• Why is the AV_PARSER_PARSE2 in ffmpeg returning empty AVPacket data for HEVC video ?

  3 août 2019, par HAlmawi

  I’m attempting to decode an HEVC encoded video (.mp4 format) and extract all the frames in C++. I installed ffmpeg and used one of their examples "video_decode.c", however the AVPacket data (pkt->data) is always NULL/empty and the size of the packet (pkt->size) is always 0.

  I have executed ffprobe on the video examples used to ensure that the videos were truly in HEVC format.

  I defined the width, height, pixel format, bit rate, and time base of the AVCodec.

  I initialized the AVPacket data to NULL and size to 0 manually.

  const char *filename, *outfilename;
  
  const AVCodec *codec;
  
  AVCodecParserContext *parser;
  
  AVCodecContext *c = NULL;
  
  FILE *f;
  
  AVFrame *frame;
  
  uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
  
  uint8_t *data;
  
  size_t   data_size;
  
  int ret;
  
  AVPacket *pkt;
  
  
  
  filename = "C:\\Users\\Me\\Downloads\\video_x265.mp4";
  
  outfilename = "E:\\output\\test%d.pgm";
  
  
  
  pkt = av_packet_alloc();
  
  if (!pkt)
  
      exit(1);
  
  //pkt->data = NULL;
  
  //pkt->size = 0;
  
  /* set end of buffer to 0 (this ensures that no overreading happens for damaged MPEG streams) */
  
  memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE);
  
  
  
  /* find the MPEG-1 video decoder */
  
  codec = avcodec_find_decoder(AV_CODEC_ID_HEVC);
  
  if (!codec) {
  
      fprintf(stderr, "Codec not found\n");
  
      exit(1);
  
  }
  
  
  
  parser = av_parser_init(codec->id);
  
  if (!parser) {
  
      fprintf(stderr, "parser not found\n");
  
      exit(1);
  
  }
  
  
  
  c = avcodec_alloc_context3(codec);
  
  if (!c) {
  
      fprintf(stderr, "Could not allocate video codec context\n");
  
      exit(1);
  
  }
  
  
  
  /* For some codecs, such as msmpeg4 and mpeg4, width and height
  
  MUST be initialized there because this information is not
  
  available in the bitstream. */
  
  c->width = WIDTH;
  
  c->height = HEIGHT;
  
  c->pix_fmt = AV_PIX_FMT_YUV420P;
  
  c->bit_rate = 400000;
  
  c->time_base = (AVRational) { 1, 25 };
  
  
  
  /* open it */
  
  if (avcodec_open2(c, codec, NULL) < 0) {
  
      fprintf(stderr, "Could not open codec\n");
  
      exit(1);
  
  }
  
  
  
  f = fopen(filename, "rb");
  
  if (!f) {
  
      fprintf(stderr, "Could not open %s\n", filename);
  
      exit(1);
  
  }
  
  
  
  frame = av_frame_alloc();
  
  if (!frame) {
  
      fprintf(stderr, "Could not allocate video frame\n");
  
      exit(1);
  
  }
  
  frame->width = c->width;
  
  frame->height = c->height;
  
  
  
  while (!feof(f)) {
  
      /* read raw data from the input file */
  
      data_size = fread(inbuf, 1, INBUF_SIZE, f);
  
      if (!data_size)
  
          break;
  
  
  
      /* use the parser to split the data into frames */
  
      data = inbuf;
  
      while (data_size > 0) {
  
          ret = av_parser_parse2(parser, c, &pkt->data, &pkt->size,
  
                  data, data_size, AV_NOPTS_VALUE, AV_NOPTS_VALUE, AV_NOPTS_VALUE);
  
          printf("pkt size: %d\n",pkt->size);
  
          if (ret < 0) {
  
              fprintf(stderr, "Error while parsing\n");
  
              exit(1);
  
          }
  
          data += ret;
  
          data_size -= ret;
  
  
  
          if (pkt->size)
  
              decode(c, frame, pkt, outfilename);
  
      }
  
  }

• av1_metadata : Error out if fragment is empty

  20 juin 2019, par Andreas Rheinhardt

  av1_metadata : Error out if fragment is empty
  If the fragment is empty after parsing (i.e. it contains no OBUs), then
  
  the check for the type of the fragment's first OBU is nonsensical ; so
  
  error out in this case just as h264_metadata and hevc_metadata do.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/av1_metadata_bsf.c

• avcodec/hevc_ps : Change num_tile_rows/columns checks to sps->ctb_height/weight

  25 juin 2019, par Michael Niedermayer

  avcodec/hevc_ps : Change num_tile_rows/columns checks to sps->ctb_height/weight
  Suggested-by : James Almer <jamrial@gmail.com>
  
  Reviewed-by : James Almer <jamrial@gmail.com
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/hevc_ps.c