[mythtv] decoding HD-PVR H.264

David Engel david at istwok.net
Tue Feb 3 16:32:53 UTC 2009

On Mon, Feb 02, 2009 at 08:18:40PM -0700, john wrote:
> While libavcodec/h264.c does treat that as a warning and not an error,  
> that warning causes it to not set the gotpicture flag.  Because  
> gotpicture is false, AvFormatDecoder::GetFrame() will continue onto the 
> next frame.  That one fails, because it is not a keyframe (and it failed 
> to parse the previous frame):
> [h264 @ 0xf39300]B picture before any references, skipping
> [h264 @ 0xf39300]decode_slice_header error
> [h264 @ 0xf39300]no frame!
> AFD Error: Unknown decoding error
> Can anyone help me understand why decode_frame() kicks back the keyframe 
> with that "unref short failure"?  I though keyframes where "self 
> contained".

I've seen those errors myself.  It could be the cause of, or at least
related to, a problem I've started to look into.  Most of the time
after skipping forward or backward on HD-PVR recording, I will get a
prebuffering pause about 0.5 seconds after playback resumes.  

David Engel
david at istwok.net

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