[Libav-user] Problems with ffvhuff and huvvyuv

James Board jpboard2 at yahoo.com
Thu Oct 17 20:55:06 CEST 2013

>And issue is probably withing avi container as it
>may not add every frame into index table.
>And when seeking you never check if returned packet actually is right
>one that you need.
>Or it could be bug in your code how you seek in file, etc...

Sorry for the top post (again).  The problem is Yahoo email.  Anyway here
is the same last message.

I did a rewrite of my code and it now works.  But I don't know why.
I modified the demuxing.c example so that it seeks to frame 0, calls
decode_packet, seeks to frame 10, calls decode_packet, etc.  I
seek to every 10th frame and call decode_packet().  I also
modified decode_packet() so that it writes an output file whenever 

'got_frame' is non-zero.  For the first four seeks (frame 0, 10, 20, 30),
'got_frame' is NULL and no output image files are written.  Then,
when I seek to frame 40, the output file for frame 0 is written.  When I seek to
60, the output for frame 10 is written.  When I seek to frame 60, the output
for frame 20 is written, etc.  Eventually, the 'flush cached frames' loop is
entered and the final files are written.

Does this make sense or sound familiar to anyone?  What is happening here?
Does this have anything to do with cached frames?  I've asked before what 'cached
frames' are but nobody answered.  Does anyone understand this?

Also, none of the above oddness happens if I use AVI files encoded with 

no codec or with lossless JPEG, or a few other codecs.
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