[mythtv-users] Enabling multirec borks usability a bit.

Michael T. Dean mtdean at thirdcontact.com
Tue Apr 20 21:48:54 UTC 2010


On 04/20/2010 04:22 PM, Tortise wrote:
> From: "Michael T. Dean"
>
> One thing to keep in mind is the overall goal of mythtv - wasn't it to 
> be the mythical convergence of all technologies into one system?  
> Correct me if I am worng, I don't think exclusion of livetv fits with 
> the original definition of mythtv?

Live TV isn't excluded.  It's just that it will only be improved by 
people who care to donate their time/effort to improving Live TV (and 
you can't count me among those people--I have plenty of other stuff on 
my TODO list for MythTV).

>> Small, but achievable goals, and all...  Make a bunch of little 
>> changes to get a huge improvement.
>
> Well I am certainly sympathetic to that notion, IMO and experience it 
> is vastly eassier to make small incremental changes than do a dump of 
> a radical change and then the pain of debugging the hell out of it....
>
>> Then, eventually, maybe some of the bigger changes will be 
>> easier/more acceptable.
>
> The holy grail seems to be having the same number of tuners as the 
> users have number of mux, so for me that's 3, given code that 
> efficiently utilises the tuners for recording and livetv.  
> (Realistically that means 2 x 500T's here = 4 tuners!)
>
>
> I did not realise that turning off multirec would also fix the issue.  
> So if I had 3 x 500T = 6 physical tuners that hardware requirement is 
> very likely to cover 99.x% of our user requirements, whether it be 
> through either of the above options.  My servers got 3 PCI slots.... 
> To make 6 I'm going to buy another dual tuner!
>
> One thing I'd appreciate a response on is the question of dedicating 
> tuners.  How hard would it be to say have 3 tuners dedicated for 
> multi-recording mux and say 3 dedicated for (uni-rec) live TV use?  As 
> we only have 3 mux, this could also work well and keep 3 live 
> frontends live.  (Not sure what one would do when 4 tried...I suppose 
> as is now....)
>
> Maybe making the first 3 tuners multi-rec and leaving the rest uni 
> might be a pragmatic solution that uses the existing code base? I 
> think it would cover it all for 1 live user.  The issue would be which 
> tuner a second live user got, I believe they'd currently get the same 
> tuner the first live tv user is using....?  Could that be a small 
> fix....(Mike can you comment please?)

Just configure your first 3 cards with, say, 3 virtual tuners each, then 
add the next 3 cards with 1 virtual tuner each (and you /must/ connect 
inputs and set virtual tuners as you're configuring your cards properly 
so you have card 1 with inputs 1,2,3; card 2 with inputs 4,5,6; card 3 
with inputs 7,8,9, card 4 with input 10, card 5 with input 11, card 6 
with input 12).  Then enable Avoid conflicts...  (See 
http://www.gossamer-threads.com/lists/mythtv/dev/369358#369358 for more 
details, but you won't need the +1 for Live TV is you have 6 physical 
tuners and 3 muxes.)

>
> Either way I'd still have an inefficient tuner use outside the "holy 
> grail" scenario.

If you only have 3 muxes, you only need 3 physical tuners with X > 
max_concurrent_recordings_and_livetv_per_mux virtual tuners defined.  
Then change channel with the EPG or using Browse all channels.  And, 
using the configuration I described at the post above, you'd likely use 
Y+1 virtual tuners where Y >= max_concurrent_recordings and the +1 gives 
you 1 extra virtual tuner for Live TV.

> The cost of tuners is relatively small compared to the surrounding kit 
> they integrate in with.
>
> The coding "cost", ie limited coding dev resource is limited.

Yep.  And that's just it.  It's cheaper for me to buy as many tuners as 
I need than it is to write (and have to maintain) code to try to do what 
you all would like to see.  (Granted, I don't/won't ever use Live TV, so 
it's easier for me to get a configuration that's perfect than it is for 
someone who wants recordings and Live TV.)

> I for one respect the dev's setting development priorities because 
> they understand the decision criteria and consequences better than I do.
>
> I am also prepared to buy another dual tuner!

Right, so everyone else has the same option as me--write code, configure 
their system within current possibilities, use EPG or Browse all 
channels, or buy hardware.  :)

Mike



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