[mythtv-users] Networking recording (IPTV) and multicast on multiple "tuners"

Michael L Torrie torriem at chem.byu.edu
Wed Jan 9 23:53:31 UTC 2008

Michael L Torrie wrote:
> I've configured MythTV from SVN to talk to my multicast IPTV system
> (h.264, MPEG-TS streams, via TCP/IP multicast).  All channels are
> broadcast simultaneously on different addresses (same port number
> though).  I can fire up multiple copies of VLC with the playlist and
> watch multiple channels (or the same channel) all at the same time just
> fine.   However in Myth, if I have currently scheduled a recording which
> is in process, if I fire up a mythfrontend and try to watch a channel, I
> just get lots of errors on the terminal like:
> 2008-01-09 15:47:47.000 [h264 @ 0x2aaaac1c01c0]warning: first frame is
> no keyframe
> 2008-01-09 15:47:47.002 [h264 @ 0x2aaaac1c01c0]top block unavailable for
> requested intra4x4 mode -1 at 34 10
> 2008-01-09 15:47:47.002 [h264 @ 0x2aaaac1c01c0]error while decoding MB
> 34 10, bytestream (234)
> 2008-01-09 15:47:47.119 NVP: Prebuffer wait timed out 10 times.
> 2008-01-09 15:47:48.449 NVP: Prebuffer wait timed out 10 times.
> Eventually I have to kill the frontend, and then the backend recording
> stops after recording garbage.
> Should not MythTV be able to record multiple streams from different
> "tuners" even though they are each using the same playlist (same set of
> addresses)?  Multicast can do this, after all, and Myth is perfectly
> capable of dealing with multiple tuners normally.

I also want to add that when I scheduled two shows on different channels
to record at the same time, Myth is happy to comply (since it has
multiple virtual tuner cards), but after just a few seconds of
recording, both recordings stop and the resulting videos just have
garbage in them.

> Any advice?
> Michael

Michael Torrie
Assistant CSR, System Administrator
Chemistry and Biochemistry Department
Brigham Young University
Provo, UT 84602

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