[mythtv-users] XvMC, Plextor Question, and Sound

[Jesse Guardiani]

Brian Wood wrote:
> So, do I understand this correctly:
>
> I've installed a Plextor ConvertX (I've run out of PCI slots).
>
> Even if I am ultimately successful in getting XvMC to work, I would  
> get no help from it in playing video from the Plextor (live or  
> recorded) as it is MPEG-4???
>   

I think that is currently correct, yes. I believe some unichrome 
hardware is capable of mpeg-4
XvMC acceleration, but I don't think any drivers/libraries support that 
functionality yet.

> Is there any work afoot to support Plextor modes other than MPEG-4?
>   

Not that I'm aware of. However, I'm interested in doing just that once 
0.19 is released. I
have a plextor, and like you I'm out of PCI slots, so the Plextor is 
really my only option if
I want a second tuner. In addition to XvMC support, recording to Mpeg-2 
would allow
for DVD burning via MythBurn.

Maybe I'm being naive, but I don't think it will be all that difficult 
to add support for mpeg-2.

> The Plextor has been working surprisingly well, but if anyone is  
> considering one, be aware that it does not embed the sound in the  
> MPEG stream, the way a PVR does. Rather it sends uncompressed sound  
> to ALSA as PCM, which requires a sound card input.
>   

MythTV then compresses this audio to mp3 using your system's CPU (by 
default - you can
turn it off in the recording profiles), so the plextor will actually 
cause mythbackend to burn a
good bit more CPU than a true PVR card.

> I guess I could replace two of my 150s with a 500, freeing up a slot  
> for a sound card, but I think I'll wait 'till the 500 support settles  
> down a bit.
>   

500's seem a bit more picky about their drivers, PCI slots, and inputs 
than other IVTV cards
too.

-- 
Jesse Guardiani
Programmer/Sys Admin
jesse at wingnet.net