[mythtv-users] mplayer -dumpstream better than myth record

Hunter McDaniel oxothuk.maps at 4dv.net
Fri Sep 14 23:45:25 UTC 2007

I'm wondering if your problem is that same as what I have with one 
particular channel, KTVD-DT in Denver.
Reception of this channel is rock-solid on a standard STB, and Myth has 
no problem with three other stations whose transmitters are located on 
the very same building with comparable power levels.

I did a bit of investigation a few months ago, and like you, found that 
I could record my problem channel just fine with mplayer --dumpstream, 
but trying to watch or record it with Myth always gave me freezes and 
lockups.  When I turned on some of the detailed logging in the backend, 
I saw that Myth was constantly detecting "discontinuity errors" in the 
PMT, and the logic to recover from those discontinuities seemed to be 
overwhelm the recording process, saturating the CPU and making it drop 
frames.  From a more detailed look at the actual frames, I could see 
that the datastream from KTVD-DT had two different PMTs interleaved into 
it, each running a different continuity counter - and hence causing a 
discontinuity on every PMT.

I don't know if the problem with your station is the same, but it might 
be worth a check.


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