[mythtv-users] duplicate callsigns? (was: Re: utterley confused)

[Karl Dietz]

On 23.06.2014 15:15, Vincent McIntyre wrote:
> Stop the mythtv-backend, and do a scan with 'w_scan -f t -c AU -X -a 0'.

Ok, so we are looking at a t_zap style channels.conf output, see
http://www.linuxtv.org/wiki/index.php/Dvbscan#After_the_scan_completes

> Here is what I get for the channel 10 multiplex in Sydney (on 219500000 Hz)
> (I took out a few spaces in the first field to keep the long lines together).
>
> ONE(TENSydney):219500000:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_3_4:FEC_NONE:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:514:672:1569
> TENDigital(TENSydney):219500000:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_3_4:FEC_NONE:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1573
> TVSN(TENSydney):219500000:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_3_4:FEC_NONE:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:518:690:1574
> ONE(TENSydney):219500000:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_3_4:FEC_NONE:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:514:672:1575
> ELEVEN(TENSydney):219500000:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_3_4:FEC_NONE:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:516:681:1576
> SpreeTV(TENSydney):219500000:INVERSION_AUTO:BANDWIDTH_7_MHZ:FEC_3_4:FEC_NONE:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:520:700:1577
>
> It's not obvious to me (without additional information from other
> sources) whether the duplicate callsign indicates exactly the same
> content in the program stream - the programid field (the last one I
> think, w_scan's output needs better documentation) is different.

Well spotted, the program_number / service_id of both "ONE" services is 
different, while the rest is identical.

So the service name ONE appears twice both have the video PID 514 and 
the audio PID 672. At this point in time both channels carry exactly the 
same content, because its two services referring to the same audio/video 
streams. But both services have different service ids, 1569 and 1575, 
these can at any point in time be changed to point to separate 
audio/video streams, e.g. to split the channel into two for regional 
news/ads. A technique called dynamic PMT.

The description over at Wikipedia does not allow me to understand which 
regional variants exist.
http://en.wikipedia.org/wiki/One_%28Australian_TV_channel%29#Availability

In MythTV terminology you likely want to set two different channel 
names, but the same callsign.

Regards,
Karl