[mythtv] SI/PSIP Parser

[Taylor Jacob]

> ]On my set top ATSC box I have to re-scan from time to time because they
> ]are always changing what minor channels exist and what not, so I
> ]suspect there may be a need for some sort of Auto-PID code instead of
> ]caching PIDs in the DB (Which I don't like the idea of caching PIDs
> ]since it takes almsot no time to get and parse the PAT and PMT).
>
> I've done some timings on this and it only takes a few milliseconds to
> get the PAT & PMT, while it takes 200-300 ms to get the first GOP.
> Unfortunately if you wait for the TVCT that also seems to take 200-300
> ms to come in. This argues for caching the TVCT info in the database.
> We don't want to wait 600 ms just to BEGIN writing the recording to
> disk.
>
> But caching the TVCT isn't so bad since the broadcasters are discouraged
> from changing the subchannel<->programID mapping very often.

Ive had the same complaints from the DVB guys about the same thing.. Maybe it will still be cached
but updated upon tuning, or some interval.  That way it can always be up to date and no user
scanning is required to keep it in sync.

You can always keep the verison of the TVCT/SDT in the channel table and just check that tis the
same and not have to hit the DB again.. (Make the assumption that if the version if the same then
everything int the DB is OK).