[vdr] Re: What about a channel logical number ?

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

Rainer Zocholl wrote:
> 
> rene@bartschnet.de(Rene Bartsch)  02.05.02 00:09
> 
> Once upon a time Rene Bartsch shaped the electrons to say...
> 
> >>
> >> Sit back for a moment and think: a unique number for each channel
> >> would have to be managed by some centralized organization. New
> >> channels would have to be assigned new unique numbers, and in case a
> >> channel "disappears", that number can't be re-used (at least for
> >> some time).
> >>
> >> Don't get me wrong - I'd love to have such unique numbers. But
> >> somebody would have to manage them. And you would have to convince
> >> all sources of channel listings to use these unique channel ids,
> >> otherwise I guess they wouldn't make too much sense...
> >>
> >> Klaus
> 
> >It mustn't be world-wide numbers, but if VDR internally would assign a
> >unique identifier for each channel, there wouldn't be problems between
> >channels.conf and timers (I had about 10 timers active on my
> >test-system and updated my channels.conf - all recorded on wrong
> >channels :-( ).
> 
> My opion is, that it is easier and more convient to use 2 lists:
> One list for the user and one list for the computer.
> 
> The "uniq" number may be the MD5-hash of channel name,
> frequency, polariationm, orbit and PID etc. That should be "uniq" enough
> and is easy to generate.
> The "uniq number" is only required to search the channel data fast
> enough for the timers and the zapping list, or?
> So such a "hash value" may be a sufficient way to go?

Why use an MD5 number? Why use the channel _name_ in the first place?
Wouldn't orbital position, transponder frequency and service id be
sufficient to identify a specific channel?

But then again, this wouldn't help if the complete channel setup
changes (as with the recent PW changes).

> The user can sort "his" zapping table as he likes.
> VDR can sort and expand the computers list as required.
> If a channel is renamed or moved the user will be warned,
> that the chanel seems to have disappeared.
> To make that more convinent a third list with the
> "old chanels" may be use ful, but not requored.
> 
> The other way is that the timers stores all relevant information
> for recording.

And what good would that do?
If the channel data changes, you'll still have to modify your timers
to reflect the new settings. Besides: storing the same information in
more than one place most likely will sooner or later mean that it will
be wrong in at least one of these places ;-)

Currently the EPG data is matched to the channels thru the service id
(or "program number" - the last parameter in 'channels.conf'). Apparently
this works quite well on Astra, where every channels has a unique service
id. But there is no need for this to be true, service ids only need to be
unique within a single transponder.

I will therefore most likely use a combination of orbital position,
transpoder frequency and service id to do this matching in the future.
Maybe such an identifier can also be used to create a user specific
"favorites" channel list. I'll look into this after the plugin interface
has been completed...

Klaus
-- 
_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
_______________________________________________________________