[mythtv] Strange EPG behavior

Steffen Immle Immle at gmx.net
Sat Apr 24 10:15:17 EDT 2004

David Engel wrote:
> On Fri, Apr 23, 2004 at 01:59:59PM +0200, Steffen Immle wrote:
>>On the PVR350's tv-out, LiveTV actually displays the full EPG (and sadly 
>>makes my box quite instable, espacially on exiting the EPG). I don't 
> This is a well known problem.  In short, the PVR cards don't like
> their graphics memory being used as a normal frame buffer while
> decoding is going on.  You can use the ivtv specific X module found at
> http://membres.lycos.fr/badzzzz/ to fix it.  It provides a virtual
> frame buffer for X to scribble on and then DMAs the results to the PVR
> using the OSD ioctls.

I'm using that module, and it made things much better (and it finally 
let's me watch software decoded stuff without stuttering). Without 
ivtvfb, the box would hang as soon as I started moving around in the 
EPG, now it "only" crashes the frontend sometimes when exiting the EPG. 
I think it was stable with ivtv-0.1.9 and myth CVS from sometime around 
February. Now I'm running ivtv-0.1.10pre2 and CVS from some days ago, 
and I experience these crashes. Not sure which upgrade caused that, and 
I didn't have time to look into this. Besides, it's not a major thing 
for me, 'cause I rarely watch live TV anyway. Btw, what does the EPG do 
differently than the other OSDs when fading away?

>>do for the normal output (minus the transparency effect). And while I'm 
>>at it, let me make a suggestion: If you (or someone else) implement an 
>>option to switch between the EPG modes, it would be nice to be able to 
>>do that for the PVR350, too. Because I actually like the preview (ie. 
> This isn't really feasible without some significant changes.  X
> doesn't know(*) about the PVRs alpha channel so Myth can't poke a hole in
> the screen for the hardware decoding to continue.  That leaves
> switching to software decoding while the EPG is up and Myth doesn't
> support switching back and forth between decoding modes.

So the only option would be to turn decoding (and thus live TV) 
completely off while in the EPG? So maybe an option to make Menu drop 
out of Live TV and into the EPG, combined with the patch that makes 
Select tune to that channel in the non-Live-tv EPG, would be an idea... 
Well, maybe not, just thinking aloud.

> (*) It might be possible to add something to the ivtvdev X module but
> somebody would have to look into it.
> David

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