[mythtv] [mythtv-commits] Ticket #1866: DVB Scanning - Remaining Issues

Zdzislaw Gorlicki zdzisekg at comcast.net
Mon Aug 21 01:19:12 UTC 2006

Rudy Zijlstra wrote:
> Janne Grunau wrote:
>> On Saturday 19 August 2006 12:27, MythTV wrote:
>>> The old behaviour can be acheived by doing the
>>> tuned scan, and then existing transport scan,
>>> as the tuned scan will populate dtv_multiplex
>>> from the NIT found on the first transport.
>> This is for a first time user confusing and for anyone else impractical. 
>> Most users of Full scan (tuned) use it since there is no full scan for 
>> DVB-S and DVB-C.
>> I looked into this 2 weeks ago and agree that it can't fixed easily. We 
>> are probably not able to have the old behaviour in 0.20 but it should 
>> be fixed sometime.
>>> Alternatively, full scan is available to find
>>> all the transports being broadcast, which will
>>> work even if the transports do not provide any
>>> information about other transports, as happens
>>> in certain countries.
>> There is no full scan for DVB-S and DVB-C. I don't think that an 
>> equivalent to the DVB-T full scan is practical for DVB-S and DVB-C. 
>> Astra 19.2E has about 100 transponders and I don't think it's a good 
>> idea to maintain for several orbital positions lists of transponders in 
>> the MythTV source code. For DVB-C we could scan the appropiate frecency 
>> tables we have already. Although it is most of the time more effort 
>> than needed.
>> Janne
> For DVB-C using the frequency tables is not a good idea. Most of the 
> European cable operators are not adhering  to any frequency table but 
> there own. Which may be different for each city. German cable is slowly 
> moving to a 8MHz raster layout. This is also not covered by any standard.
> The best way to detect all streams on DVB-C is by a slow frequency scan, 
> with 125MHz step size (or 250MHz, depending on tuner capability). yes, 
> this takes time. It is the only way though. And please, please, do 
> ignore NIT while you are doing this?? Because many cable operators do 
> not provide a valid NIT-actual. They provide many NIT-Other, but no, or 
> no valid NIT-actual..... And yes, i know Germany is the exception to the 
> rule here, as the big three cable operators in Germany do provide a 
> valid NIT-actual.
> Cheers,
> Rudy
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don't want to get off topic here, but since we're on the subject I 
thought I bring it to your attention that scanning of any of the 
echostar satellites is not possible. actually, even tunning to a channel 
on those sats is not possible. Please let me know if you need me to open 
a ticket and provide logs etc.

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