[vdr] Request: E parameter in channels.conf for epg scan

Udo Richter udo_richter at gmx.de
Tue Dec 14 22:11:41 CET 2010


Am 14.12.2010 21:20, schrieb Luca Olivetti:
> Right now I have a recording going on. If I press the "up" channel past
> the last channel on the same transponder, vdr is unresponsive for ~30
> seconds.
> I guess that sqlite, with a well formulated query and the right indexes,
> would take a fraction of a second to realize that there are no more
> channels in the same transponder.

Actually, what VDR here does is to tune to each and every channel in
your channels.conf after the current, until there's a channel that
successfully tunes. Doing an additional sql query for each and every
channel in your channels.conf wouldn't improve that, I guess.

Two things make this a slow thing: First, the channel list is a linked
list, and if you switch from 1000 to 1001, VDR runs through the list
starting at 1 until 1001. If 1001 doesn't tune, VDR runs again from 1 to
1002. A C++ map would speed things up a lot, a persistent channel
iterator even more.

The second thing is the tuning. "Get next channel on this transponder"
sounds simple, but actually deciding whether a channel is tuneable
involves 17 different rules that get checked against each device, plus
probing the CAM whether the channel can be decoded by the CAM. I think
that part is even slower than the whole channel list.


But after all, there are more important things that need work, than
speeding up such special cases.


Cheers,

Udo



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