[mythtv] [PATCH] HDTV Recorder Patch

Daniel Thor Kristjansson danielk at mrl.nyu.edu
Thu Dec 2 21:10:10 UTC 2004


On Thu, 2 Dec 2004, Taylor Jacob wrote:
]>   1) The PCR stream is recorded, even if it is not in the PMT.
]>      This isn't in the old hdtvrecorder, but is needed to produce
]>      valid streams when recording John's local CBS station. Thanks
]>      go to Taylor Jacob for the info that lead to this bug fix.
]
]What is sent as bytes 9/10 of the PMT then?  Thats where the PCR PID is defined
](of course its anded with 0x1FFF to be within MpegTS PID Range).

Yes, the problem was that we used to bail if this pid was not in the 
list of streams described in the PMT, like say the audio and video 
streams are. This is because we need to update the PCR pid in the new 
PMT table if we change the pids of the audio and video and one of these 
contains the PCR reference stream. If we were still doing pid rewriting 
we would need to do some kind of collision avoidance to properly deal 
with seperate PCR streams and potentially rewrite the PCR streams pid 
as well. But since we no longer do pid rewriting, this was a very easy 
fix; I just add the PCR pid to the list of streams we record if it is 
not already an audio or video stream we are recording.

In other words, the ease of this fix was a payoff from fixing ffmpeg to 
cope with new PMT tables in the transport stream. ;)

-- Daniel


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