[mythtv] OpenCable stream type & #2556

Stuart Auchterlonie stuarta at squashedfrog.net
Mon Oct 16 13:49:25 UTC 2006

On Mon, Oct 16, 2006 at 09:35:30AM -0400, Daniel Kristjansson wrote:
> > One way to handle #2556 might be to ignore alternative video
> > streams once we have found a valid stream. Perhaps using
> > the stream type as a preference.
> I think we should only remap 0x80 to 0x02 if the sistandard is "atsc",
> a longer term fix is to have the channel scanner set the sistandard
> type to "opencable" for OpenCable transports and only do the remap
> when the sistandard is "opencable". Hopefully transports won't mix
> sistandards, if they do we will have to move this column from the
> dtv_multiplex table to the channel table.

I think we should implement this by setting the sistandard to

I'd say it's unlikely that they will mix standards on a given
mux. The head end equipment is normally setup for a specific
broadcast type and then left alone.

> > The PMT debugging printout says that it'll use the first video
> > stream found, which is contrary to what we do. Is there a situation
> > in which things would break if we chose the video stream in this
> > way?
> I don't know if this would break MHEG. But this debugging was written
> when we only supported a single video stream. We now partially support
> multiple video streams for MHEG, and in the future we will support
> it for ATSC and OpenCable Interactive TV applications.

For MHEG it selects video streams via the component tag.
When there are multiple video streams they tend to broadcast the
additional streams under the private stream type, and pick up
the stream that way. In this case we should just make sure we
pass the private streams through unmolested and leave the MHEG
engine to decide what to do with it. Believe this is what we now do.

I think i'll code up and test selection of the first video
stream listed in the PMT as the default behaviour


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