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

[Doug Larrick]

Tom Dexter wrote:
> 2008-10-01 03:10:59.898 [mpeg2video @ 0xb7306028]warning: first frame
> is no keyframe
> 2008-10-01 03:11:01.567 [mpeg2video @ 0xb7306028]warning: first frame
> is no keyframe
> 2008-10-01 03:11:18.429 [mpeg2video @ 0xb7306028]warning: first frame
> is no keyframe
> 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.

Whether you see this error depends on the encoding equipment used to
assemble the transport stream.  This equipment could be at the network or
at your local station, which is why people in different parts of the
country will see / not see this problem.

A workaround is to rebuild the seektable, perhaps as a user job after
every recording on these stations.  Rebuilding the seektable does the
partial stream parsing that is required.  But it doesn't work currently
because Myth attempts to use MARK_GOP_START markers on these recordings --
as their keyframes are not on a regular cadence, MARK_GOP_BYFRAME should
be used instead.  The solution to *that* problem is here:
http://svn.mythtv.org/trac/ticket/1088

-Doug