[Libav-user] avcodec_decode_video2 returns 0 in third parameter

[francesco at bltitalia.com]

Hi to all
I can't decode a field because avcodec_decode_video2 returns 0 in the third
parameter either if the stream is correct (i displayed it with other
programs). Here is the code:

  pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
  if(pCodec==NULL) {  str1.printf("Unsupported codec ! (type
%d)",pCodecCtx->codec_id);Memo1->Lines->Add(str1); goto end_conv;}

  // Allocate video frame
  pFrame=avcodec_alloc_frame();

  // Open codec
  if(avcodec_open(pCodecCtx, pCodec)<0) {  Memo1->Lines->Add("Unable to open
codec!"); goto end_conv;}

  err = av_read_frame(pFormatCtx, &packet);
  if(err<=0) Memo1->Lines->Add("Error or end of file during read_frame");
  if(packet.stream_index==videoStream)
  {
  //    avcodec_get_frame_defaults(pFrame);
      frameFinished = 0;

      // Decode video frame
      err = avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished,&packet);
 }

at this point frameFinished is zero.  In the packet buffer the stream is
correctly loaded, and the err value is exactly the number of bytes read from
file (the file is composed of only one field).
Any idea ?