[mythtv-users] Frames per second?

[jeff at burstable.net]

Thanks, I'll try the gbuffers option tonight when I get home.

--Jeff


On Mon, 21 Apr 2003, Ray Olszewski wrote:

> At 03:32 PM 4/21/2003 -0400, jeff at burstable.net wrote:
> >It doesnt appear to be 'torn'.  The best I can describe it would be if
> >playing a PC game on a underpowered pc and the FPS drop under 20 fps or
> >so.  Typical CPU usage is about 60% - 70% when watching live tv.  Oh and
> >the deinterlace filter is one.
> 
> It is always hard to be certain from these sorts of descriptions (the one 
> above and your earlier one), but what you describe sounds like the capture 
> process is dropping frames for some reason. The usual one is that the image 
> is sufficiently rich in complexity that the encoder can't work fast enough 
> on one frame before it has to get the next one, so some are lost. In this 
> context, "complexity" is anything that makes encoding harder to do, 
> including simple noise (I get a 50% drop rate in frames when there is 
> nothing connected to the Television input, for example).
> 
> Panning motion is a good way to introduce this sort of complexity ... I 
> don't tape sporting events, but I've seen similar sorts of problems in The 
> Simpsons, at the beginning where the "camera" (the animation PoV) pans over 
> the field full of supporting characters, or a bit earlier where sometimes 
> it pans and zooms to the school for a Bart Blackboard Quote.
> 
> If I'm right, I think your only options are (A) get a faster computer or 
> (B) reduce the pixel size of the capture.
> 
> Oh, one thing you should check: when you load the bttv module, are you 
> including a suitable gbuffers= argument? (I usually use gbuffers=32 with my 
> non-Myth systems, and I expect I'll do the same when I finally get Myth 
> running here. If MythTV doesn't work the way I'm assuming here, I hope 
> someone will correct me.) This can help buffer against brief bursts of 
> complexity in the frame sequence.
> 
> 
> 
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