[Ffmpeg-devel] RE: Lowres option problem

[Roberta Weber]

Hi!

I tryed to set CODEC_FLAG_EMU_EDGE in AVCodecContext->flags, 
but the lowres = 3 still causes segmentation fault error.

When I used lowres = 1, I didn't have problem. I used the 
following code. Any suggestion, please ? 

 int
main (int argc, char *argv[])
{
  AVFormatContext *pFormatCtx;
  int i, videoStream;
  AVCodecContext *pCodecCtx;
  AVCodec *pCodec;
  AVFrame *pFrame;
  int numBytes;
  uint8_t *buffer;

  av_register_all ();

  if (av_open_input_file (&pFormatCtx, argv[1], NULL, 0, NULL) != 0)
    return -1;
  if (av_find_stream_info (pFormatCtx) < 0)
    return -1;

  dump_format (pFormatCtx, 0, argv[1], 0);
  videoStream = -1;

  for (i = 0; i < pFormatCtx->nb_streams;  i++)
    if ((pFormatCtx->streams[i]->codec)->codec_type == CODEC_TYPE_VIDEO)
      {
        videoStream = i;
        break;
      }
  if (videoStream == -1)
    return -1;

  pCodecCtx = pFormatCtx->streams[videoStream]->codec;
  pCodecCtx->flags = CODEC_FLAG_EMU_EDGE;
  pCodecCtx->lowres = 3;
  pCodec = avcodec_find_decoder (pCodecCtx->codec_id);
  if (pCodec == NULL)
    return -1;

  if (pCodec->capabilities & CODEC_CAP_TRUNCATED)
     pCodecCtx->flags |= CODEC_FLAG_TRUNCATED;
  if (avcodec_open (pCodecCtx, pCodec) < 0)
    return -1;

  pFrame = avcodec_alloc_frame ();
  numBytes =
    avpicture_get_size (PIX_FMT_RGB24, pCodecCtx->width, pCodecCtx->height);
  buffer = new uint8_t[numBytes];

  while (GetNextFrame (pFormatCtx, pCodecCtx, videoStream, pFrame))
    { //...
    }

  delete[]buffer;
  av_free (pFrame);
  avcodec_close  (pCodecCtx);
  av_close_input_file (pFormatCtx);
  return 0;
}

Thanks,
Roberta.

> -----Original Message-----
> From: ffmpeg-devel-bounces at mplayerhq.hu 
> [mailto:ffmpeg-devel-bounces at mplayerhq.hu] On Behalf Of Roberta Weber
> Sent: Friday, September 22, 2006 3:16
> To: ffmpeg-devel at mplayerhq.hu
> Subject: [Ffmpeg-devel] Lowres option problem
> 
> Hi,
> 
> I used lowres = 3 in my code and this option causes 
> segmentation fault in the first  GetNextFrame:
> 

>Did you set CODEC_FLAG_EMU_EDGE in AVCodecContext->flags? It is
>necessary, although I do not know what it means exactly or why it is
>needed. Anybody knows?
>
>If you are using libavcodec alone (i.e. without libavformat) be sure to
>call avcodec_init() before calling avcodec_register_all() (with
>libavformat they are both called from av_register_all()).
>
>Best,
>
>Diego
>
>
>Diego Santa Cruz, PhD
>GE Security
>Engineered Systems EMEA
>Research Scientist
>
>T +41 21 695 0019
>F +41 21 695 0001
>E diego.santacruz at ge.com
>www.gesecurity.net
>
>Victoria House
>Route de la Pierre,  22
>1024 Ecublens
>Switzerland
>VisioWave sarl 

 		
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