[linux-dvb] DVB file formats

Felix Domke tmbinc at elitedvb.net
Fri Jun 17 01:55:01 CEST 2005


Andrew de Quincey wrote:
>>>[Presets]
>>>Number=ONID:TSID:SID
>>I can't think of a better/clearer structure than this - I've put an example
>>up on the wiki:
>>http://www.linuxtv.org/wiki/index.php/File_Format_Comparison#Ideas_for_a_pr
>>esets_file_format
Looks good, so far.

Some people like having their channels renamed. (Yes, this is another
thing which shouldn't be required, but people insist on doing this,
because it works for their 100$ el-cheapo receivers who doesn't care
about real DVB at all..).

So we might need additional service attributes, to rename a channel. It
could be useful to have a service under different names in different
presets.

Sorry, I know that this is a stupid feature, but endusers resist on it.
We should at least make an optional additional attribute, maybe we could
keep this as generic as possible, for example to assign special stuff
(icons, volume presets, ...) per service.

It has to be decided where this data has to be stored, for example in
either the presets data or seperated...

>>Now however, the multiplex differentiators are the problem (for
>>distinguishing between transponders with the same IDs). Does anyone have
>>any suggestions as to good numbers to use?
>>Obviously they have to be based on the frequency somehow, but they also
>>have to take into account tuning varaiations between people's systems (e.g.
>>different LNB drifts).
>>The first thing that springs to my mind is something like the following:
>>DVBS: ((frequency / (symbolrate/1000)) << 1) | polarisation
>>DVBT: (frequency / bandwidth)
>>DVBC: (frequency / symbolrate)
Looks good.

I don't think it's possible to find a real solution here. The
user-selected frequency can always be on a "border" to the next id.
However, i think that only a few channels need this stuff. If presets
don't work on these few channels, it won't ruin everything.

(Sure, if we find a better way, this would be far better).

Felix




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