[mythtv-users] Wrong Channel when recording?

[Michael T. Dean]

On 05/13/2015 12:02 PM, Roger Martensson wrote:
>
> Hello!
>
> I'm trying to find out if I'm seeing a bug or not. Maybe someone of 
> you could help me. I think I am doing all the right things.
>
> This is what happens. This is on a DVB-C setup.
> I have two channels that contain the same content and are on the same 
> input. (Same cardid)
> These two channels are the same except one of them is in HD.
> So I combined them into one channel. The HD-channel has priority of 0 
> and the SD-channel has -1.
>
> When looking in mythweb is looks like it is selecting the HD-channel.
> When looking in the mythbackend log it says it selects the HD-channel. 
> It selects the right cardid and right chanid.
>
> But the result is that it don't record from the HD-channel.
>
> When looking in the database the data seems correct. At looking at the 
> mplexid for the channel it seems to point at the right frequency 
> (compared to a w_scan I did earlier).
>
> What else could I do to debug this? Any debug flags I could use to 
> give me more information?
>
> This is mythtv 0.2u on a 32-bit mythbuntu based on 12.04. Using a 
> fixes installation installed a week ago (since this mail was sent).
>
> Any help would be appreciated.
>

Channel number is used only to allow quick channel changes in Live TV 
(and, if you've selected ordering by channel number, for ordering the 
guide).  You can set channel number to anything you like.

XMLTV ID is used only for linking your listings data from your listings 
provider with channels in your MythTV database.  Changing it has no 
impact whatsoever on scheduling (other than the impact from putting 
different listings data in the database).  You don't need to mess with 
this.  You don't need to have "different XMLTV IDs".  That said, the 
"HDTV only" filter and the "HDTV Priority" are based on the HDTV flag 
specified by your guide data, so if you want to use that filter or 
priority, you'd have to have different guide data where the data for the 
HDTV channel flags content as being HDTV.  However, the HDTV filter and 
the HDTV priority are not what you want.

Call sign is used to specify that 2 channels are completely identical 
for all scheduling purposes--and you have no preference whatsoever which 
channel is used to record a show.  By putting the same call sign on the 
2 channels, you're saying, "MythTV, I really do not care at all which 
one of these channels you use to record the show because they are 
completely identical."  Therefore, MythTV schedules the recording and 
one of the channels is used.

Setting a channel to have the same channel number and the same call sign 
tells MythTV to collapse that channel into one single entry in the 
guide.  This is the case because when given the same channel number and 
call sign, there is truly no distinction--you can't tune a specific one 
in Live TV because they both have the same channel number and you can't 
say to record off a specific one because they have the same call sign.  
Therefore, there is no reason to show that 2 channels exist.

If you want to be able to control which channel is used to record shows, 
have separate call signs.  If you want to be able to control which 
channel you're watching live, have separate channel numbers.

If, however, you want to be able to record shows and most of the time 
record off the HDTV one, but you will accept a recording off the SDTV 
one when "necessary", use a current version of MythTV (0.27-fixes) and 
specify channel priorities (with either a negative channel priority on 
the SDTV channel or a positive channel priority on the HDTV channel).  
Note that channel priority is not tuner priority, nor scheduler order, 
nor Live TV order.  It's channel priority.

The best solution, though, is to have enough tuners to record what you 
want.  If you're getting SDTV recordings because you don't have enough 
tuners to record everything you want so you're using multirec to fake 
having additional recording capability, you need more tuners that can 
record from the HDTV channels.  So, while you can continue to work 
around having insufficient tuning capability for your recording desires, 
you'll also need to be prepared to live with the occasional SDTV show 
(after all, that's the choice you've made--get some shows in SDTV so I 
can multirec to record more shows and save money on buying another 
tuner).  That said, if you configure properly, it will do as well as it 
can to do what you want, but you'll have to live with the bad recordings 
when it can't.

Mike