[mythtv] [mythtv-commits] Ticket #1866: DVB Scanning - Remaining Issues

Stuart Auchterlonie stuarta at squashedfrog.net
Tue Aug 22 14:11:08 UTC 2006

On Tue, Aug 22, 2006 at 09:06:15AM -0400, Yeasah Pell wrote:
> Stuart Auchterlonie wrote:
> >
> > Okay, this is doable, but is going to require some thought on
> > the best way of implementing it.
> >
> > I suspect the cleanest way of implementing this will be to
> > expand the list of locations in the country list, and then
> > behind the scenes encode in the exceptions to what we are
> > looking for.
> >
> > In this case
> > German Cable { require SDT = yes, require NIT = no }
> >
> > plus whatever we need in terms of the frequency list to
> > scan....
> >
> >   
> While you're considering that, keep in mind that one of the NA 
> commercial providers (dish network) screws up their SDTs by broadcasting 
> the exact same SDT stream (which includes information on every transport 
> on their network) on all transports -- in addition to having a 
> ~30-second SDT loop time, this also means that the desired SDT is almost 
> always a SDT-other (and SDT-actual is for a different tp), and the only 
> way to get the SDT on that network is to match by transport ID instead 
> of matching by actual/other type (and you have to listen for SDT-other 
> too of course) The NITs are similarly all-inclusive, but they are 
> properly marked as other vs. actual (and the loop time is just a few 
> seconds since the NIT data is considerably smaller)

So Dish Network = { sensible SDT = no, only useful table = PMT,
NIT = vaguely useful }

> So of course scanning and tuning do not currently work very well on this 
> provider. You can hardly blame mythtv for that given the flagrantly 
> noncompliant stream, but it would be nice if it could be made to work 
> nevertheless. (Tuning is another matter entirely -- even if you knew 
> enough to pick out the SDT-other you wouldn't want to wait up to 30 
> seconds for it to come around on the stream, so tuning would have to be 
> SDT-less to give reasonable performance -- Daniel was talking about 
> allowing DVB PAT/PMT tuning with a tsid match a while back, and that 
> would certainly work in this case)
> I'm only mentioning that again because it could possibly be another 
> thing handled by an exception list...

The more I think about this the more it becomes obvious that a more
generic framework is required to support all the oddities and non
conformances that exist around the world....


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