[mythtv] Adding support for R5000 STB

Daniel Kristjansson danielk at cuymedia.net
Fri Feb 22 14:28:18 UTC 2008

On Thu, 2008-02-21 at 19:02 -0800, Alan Nisota wrote:

> The problem I have at the moment is that while the STB constantly 
> monitors the PAT, it only reads the PMT when a channel is changed.  I 
> can sort of fake it by manually changing the channel after starting a 
> recoding in myth, but Myth seems to need several (at regular intervals?) 
> PMT packets in order to generate a stream it is happy with.

MythTV only needs a PMT following a PAT update. Are you working with
MythTV svn? You should be able to base your recorder on the Firewire
or HDHomeRun recorders.

> I'm not really clear on how all the DTV stuff works in Myth, but the 
> streams I record with Myth can be played in mplayer, so I assume the 
> problem is simply that the recorder/playback code doesn't know which 
> PIDs are needed for audio/video

MythTV gets the PIDs from the PMT, it does not try to detect them any
other way. If your broadcaster does not produce PMT's at all you can
detect the video and audio streams in the signal monitor and synthesize
PMT's. There are methods for creating PMT's from scratch within

> I'm thinking about either caching the last PMT and replaying it every 
> time I see a PAT, or possibly building it from scratch based on the 
> currently available PIDs, but I was wondering if there was a better way 
> or if I'm perhaps missing something here.

If there are some PMT's that should allow MythTV to get a signal lock
and record the stream. The frontend likes to see PMT's shortly after
it sees a PAT, so you will want to replay those in the recorder if they
are infrequent in the broadcast stream itself.

-- Daniel

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