[mythtv] Re: Help!
Daniel Thor Kristjansson
danielk at mrl.nyu.edu
Wed Dec 1 01:10:30 UTC 2004
On Tue, 30 Nov 2004, John Patrick Poet wrote:
]All of a sudden, I cannot record my CBS channel. This has nothing to do with
]your hdtvrecorder patch. I can't record that channel with a pure CVS install
]either. I am hoping you can help me figure out why. I have attached the
]output from "mythbackend -v record", with your v32 patch in place.
]I replace the assert in MPEGStreamData::CreatePMT with:
] assert(pcrpidIndex>=0); // there must be some reference stream
] if (pcrpidIndex < 0)
] VERBOSE(VB_RECORD, QString("pmt.FindPid(0x%1) failed")
] .arg(pmt.PCRPID(), 0, 16));
] return false;
]The output shows that it is failing to find pmt pid 0x1ffe in the video stream.
]My other channels work okay. Do you see anything to explain this?
It looks like CBS is sending out a bad stream. The PCRPID should tell
you which stream is the reference stream for timecodes. This should be
either the video or audio stream. But it looks like CBS is saying the
reference stream is 0x1ffe which isn't even in the PMT table (is it
present at all?). I don't think we actually use the PCR in any of our
A/V sync methods so it might be safe to just assign the PCRPID to the
video stream. I don't know if ffmpeg is using the PCR timecodes though...
Of course, it maybe that it is valid to use a completely seperate stream
for PCR than the video and audio. Someone with the MPEG spec should be
able to confirm this. In that case we should record the PCR stream...
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