[FFmpeg-devel] [PATCH] another stab at improved dv probe

Maksym Veremeyenko verem
Sat Sep 26 17:34:06 CEST 2009

Reimar D?ffinger ???????(??):
> Hello,
> another attempt at dv probe. It is still on the simple side, checking
> that the distance between the section header difs is exactly 12000 bytes
> or also checking the video header difs etc. is possible, but currently I
> am still going for "as stupid as I can get away with".
Why do not check for DIF sequence integrity instead of some _magic bytes_?

Each DIF sequence has 150 80-bytes packets that has fixed order (i 
thinks: SMPTE 314M, Figure 4):

Header         1 block
Subcode        2 block
VAUX           3 block
Audio-Video    9*(1 audio block + 15 video blocks)

each block has ID0..ID2 bytes that describe SCT, Dseq, DBN values that 
makes easy to check packets ordering numbers, proper packets type order, 
  membership of the same sequence

Where are at least 10 DIF sequences for ONE frame...

Maksym Veremeyenko

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