[mythtv-users] Re: hdtv on low end hardware

[jimoo at rcn.com]

Hi Mike,
  Thanks for your response. I did read that section of the 
mythtv HOWTO but it seems to create even more questions. 

I think my confusion comes from having previous experience 
with the pvr 350. With the pvr 350, the encoder encoded the 
analog video to an mpeg2 file and the mpeg decoder hardware 
handled all the decoding and left my cpu mostly idle. 

In my current setup I have swapped the pvr 350 encoder for 
the hd5000 card which takes an existing mpeg2 stream and 
writes it to a file. Not much for the cpu to do there. I have also 
swapped the pvr 350 decoder for the nvidia card. If the card 
works as nvidia claims, it should handle all of the decoding. 
Again, there shouldn't be much for the cpu to do. It doesn't 
make sense then that using mpeg decoder in the graphics card 
should also require a 2 ghz pentium which is the equivalent of a 
super computer only a decade ago.

So I have made some progress. As I described before, 
watching standard def was mostly smooth with minor stutters. 
Watching hd had major stutters and was unwatchable. I figured 
out that I didn't have the Xvmc switch turned on in mythtv. 
When I turned on that switch, things changed.

With the Xvmc switch turned on in mythtv, both standard def 
and high def tv playback was smooth but both were playing 
back at half speed. I don't have any audio hooked up at the 
moment so I don't know how the audio sounded. 

I ran the "top" command and the cpu was running at 75% so it 
doesn't seem like it was truly maxed out.

So has anyone experienced xvmc playing video at half speed? I 
checked my hard drive already to make sure it had dma 
enabled etc.