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

Michael L Torrie torriem at chem.byu.edu
Wed Jan 9 23:50:45 UTC 2008

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.

Any advice?


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

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