[mythtv-users] Two odd issues with NBC DTV recordings

David Engel david at istwok.net
Thu Oct 2 17:19:35 UTC 2008


On Thu, Oct 02, 2008 at 12:12:27PM -0400, Doug Larrick wrote:
> Tom Dexter wrote:
> > 2008-10-01 03:11:24.902 [mpeg2video @ 0xb7306028]warning: first frame
> > is no keyframe
> >
> > I believe they're from NBC recordings as well.
> 
> The DVB recorder is not properly finding keyframes on some HD recordings:
> http://svn.mythtv.org/trac/ticket/2849 , which was marked as a duplicate
> of http://svn.mythtv.org/trac/ticket/799 .  The solution is to do a more
> thorough parsing (partial decoding) of the video stream while it's being
> recorded.

I missed the first message in this thread so I would have responded
earlier.

I noticed this problem for a few weeks already and finally figured it
out the other night.  The problem is NBC is encoding its video with
keyframes further apart than the MythTV dtvrecorder expects.
Consequently, the dtvrecorder thinks there aren't any keyframes and
inserts seektable entries for non-keyframes.  I'm going to check in a
change shortly which makes the dtvrecorder be a little more patient
waiting for keyframes.

While I'm at it, is anyone experiencing audio underruns with OTA Fox
recordings?  That's another problem I'm still working on.

David
-- 
David Engel
david at istwok.net


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