[FFmpeg-user] Decoding XDCAM 4:2:2 using libavcodec-5.5 : error 0xbebbb1b7 (AVERROR_INVALIDDATA)

[Marton Balint]

On Tue, 1 Apr 2014, francesco at bltitalia.com wrote:

> I post this message on libav list too, but no one response.
> Hi to all
> I have written a code for decoding IMX-D10 at 30, 40 and 50 M and works
> fine.  Attempting to decode XDCAM 4:2:2 at 1920x1080 it seems that only
> first frame (I-Frame) is decoded.  After this I receive the error
> 0xbebbbb1b7 from avcodec_decode_video2 routine.  Here is the code:
>
> pCodec = NULL;   pFrame = NULL;  pCodecCtx = NULL;
>  av_init_packet(&packet);
>
>  pCodec=avcodec_find_decoder(CODEC_ID_MPEG2VIDEO);
>  if( pCodec==NULL)
>  {   str1.printf("Error at frame %ld: Unable to find CODEC_ID_MPEG2VIDEO
> exited",frmcnt,err);smsmemo->Memo1->Lines->Add(str1);
>     errDS10 = -3; goto end_convDS10;
>   }
>  pCodecCtx = avcodec_alloc_context3(pCodec);
>  // Allocate video frame
>  pFrame=avcodec_alloc_frame();
> // Open codec
>  if(avcodec_open2(pCodecCtx, pCodec,NULL)<0) {
> smsmemo->Memo1->Lines->Add("Unable to open codec!"); errDS10 = -5; goto
> end_convDS10;}
>
>  packet.size = bfsz; // This is the size passed to the routine
>  packet.data = fbuf; // This is the buffer passed to the routine
>
>  frameFinished = 1;    err = 0;
>  do
>  {
>  // Decode video frame
>   err = avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished,&packet);
>   if(err<0)
>   {  str1.printf("Error (%lx) at frame %ld returned from
> avcodec_decode_video2, exited",err,frmcnt); smsmemo->Memo1->Lines->Add(str1);
>     errDS10 = -7; goto end_convDS10;
>   }
>   Application->ProcessMessages();
>
>  }
>  while ((!frameFinished)&&(packet.size>0))  ;
>
> The first frame is decoded correctly; is an I-Frame and these are the first
> bytes of header:
>
> 00 00 01 B3 78 04 38 33 7A 12 22 02 10 20 20 26
> 20 26 2C 2C 2C 2C 2C 2C 34 30 34 36 36 36 34 34
> 34 34 36 36 36 3A 3A 3A 44 44 44 3A 3A 3A 36 36
> 3A 3A 40 40 44 44 4A 4C 4A 46 46 44 46 4C 4C 50
> 50 50 60 60 5C 5C 70 70 74 8A 8A A7 10 11 11 12
> 12 12 13 13 13 13 14 14 14 14 14 15 15 15 15 15
> 15 16 16 16 16 16 16 16 17 17 17 17 17 17 17 17
> 18 18 18 19 18 18 18 19 1A 1A 1A 1A 19 1B 1B 1B
> 1B 1B 1C 1C 1C 1C 1E 1E 1E 1F 1F 21 00 00 01 B5
> 18 24 00 01 01 00 00 00 01 B5 21 01 01 01 1E 02
> 21 C0 00 00 01 B8 00 08 00 40 00 00 01 00 00 8B
> 22 10 00 00 00 01 B5 ...
>
> as you can see from first pachet header (00 00 00 01 00) is an I-Frame (byte
> 5 is 0x8B that is 10001011 and insulating bits 3,4 and 5 we have 1 =>
> I-Frame). Second packet is an B frame, here is header:
>
> 00 00 01 00 00 1A D7 83 B8 00 00 01 B5 84 45 4B
> 9C 00 00 00 01 B5 38 40 80 80 98 80 98 B0 B0 B0
> B0 B0 B0 D0 C0 D0 D8 D8 D8 D0 D0 D0 D0 D8 D8 D8
> E8 E8 E9 11 11 10 E8 E8 E8 D8 D8 E8 E9 01 01 11
> 11 29 31 29 19 19 11 19 31
>
> we have 0x1a that is 00011010 and now bits 3,4and 5 are 011 that identify a
> B-Frame.  I receive error till next I frame.  There is something I'm missing
> or it's a bug (or limit ) of this version of libavcodec ?

Have you tried it with ffmpeg git head? Does ffplay play all frames? If 
you can, please upload a sample somewhere.

Regards,
Marton