[mythtv] Re: [patch] DVB auto-pid, take 2

[Kenneth Aafløy]

On Monday 09 February 2004 07:34, Base Commander wrote:
> Thanks for the feedback, Kenneth.
>
> Agreed- I can see why this could cause issues.  I'm very much in favour of
> eliminating the dvb_pids table, since most DVB receivers would normally use
> the PMT to determine the correct PIDs.  We can use the cached PMT from the
> channel table (if available) to read out the last transmitted PID and just
> re-use it.
>
> The reason that I'm hoping to get this in is that I've got a full
> NIT-scanning implementation that we can use to auto-determine the available
> channels, given an initial transponder's tuning information.  It's a lot
> cleaner to do the PID detection at channel switch time, rather than channel
> scan time, especially since some channels may come on/offline during the
> day.

This is just lovely, and equally simple. I was thinking about replcing the 
database data with the tag/descriptor that conveys the DVB parameters for all 
DVB types, and making a common decoder for it, but that might be overkill 
(although, I belive channel movement could be catched with that..).

> To address the multiple-audio-PID issue - should we have a dvb_lang table
> with language priority for each channel source?  We could just use the
> following logic:
>
> 1.  If one or more of the audio PIDs in the PMT match the dvb_lang table,
> use the one with the highest priority.
> 2.  If there are more than one audio PID in the PMT with the same language,
> and this language is the highest priority, take the first one (in PMT
> order).
> 3.  If there are no audio PIDs with languages in the dvb_lang table (or
> none of the PIDs have language identifiers), take the first one (in PMT
> order).
>
> This should handle all of the channels that I can see here.  Most of them
> have either no MPEG language tag, or "eng" as the specified ISO language.
>

Yea, I belive it would handle the most cases, but should not the list not only 
be specific to DVB, but MythTV as a whole. I you want, I cold code up the 
priority list for you, so that you have your hands free for the actual 
selection/decoding stuff.

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-- 

Kenneth
ke-aa at frisurf.no