[mythtv] Suggestion for improving SLOW channel changing in LiveTV.....

Ed W lists at wildgooses.com
Fri Sep 9 14:37:41 UTC 2005

> But with Browse mode, LiveTV "channel surfing" is pretty much 
> unnecessary.  The original complaint was because it takes time to 
> switch channels.  You don't need to switch channels to know what is on 
> a given channel so when you do find one that is interesting, the 2 
> seconds it takes to change to that channel is far less of a problem 
> than eating that 2 seconds with every change without browse mode.

You are reducing *choice* though.  Some people are very visual and want 
to just flick until they find something they like

I would personally like to see the channel change time speeded up, at 
least for the case when backend and frontend are on the same box

I have at various times done some experimenting with this to see what 
can be done and by reducing the buffering a little and taking out some 
redundant pausing I was able to get the channel change time down to 
around 200ms on my DVB-T setup. 

However, then some other changes went in and change times went sky high 
again, and I ran out of time to fiddle with it much more.

I believe at least 50% of the channel change time can be removed from at 
least the DVB channel change code.  It should be possible to get the 
channel retuning done in around 50-100ms with a DVB-T card (or less) and 
then some small buffering on top would be less than 0.5s changes.

I have posted various questions on this in the past, but no one with 
more knowlege of the code flow has shown any interest in helping out.  I 
don't have infinite time so I have stopped working on it for the time being.

My suggestion is to stop bitching about the time change and put in some 
timing statements into the channel change code.  Find out which bits are 
slow and then bang on about *that* bit here on this list.  At least that 
way it's specific and constructive

Ed W

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