[mythtv-users] My experience with HD video and the Nvidia 6200TC

[Jonathan Rogers]

Gary Dezern wrote:
> 
>> I am currently using a Radeon 8500 with the X.org 7.0 radeon driver
> and
>> an LCD TV connected via DVI. It works fine except that the
> Athlon64
>> 3700+ CPU is sometimes overloaded playing and
> deinterlacing 1080i. I
>> expect that to change when I switch the
> CPU to an Athlon 64 X2 3800+.
> 
> Depending on what threads myth is
> using, and how, you might find that playback is WORSE with the 3800
> X2.  A simple test would be to playback 1080i now, and run 'top' on
> the FE machine.  If you only see a single "mythfrontend"
> process in the top 10, then hit "H" (capital) to tell top to
> show threads.  If it's a single thread thats eating most of the CPU,
> then having 2 cores (each slower than your 3700) won't help.  If it's
> multiple threads each eating about the same amount of CPU, then the dual
> core might help.

Yeah, I'm fully aware of that the application needs multiple threads to
take advantage of two CPUs. Even though I'm seeing that one mythfrontend
thread takes the lion's share of CPU time, I do know that the X and
mythfrontend processes each take significant CPU time, so they should
split between CPUs nicely. I currently have the X2 3800 in my desktop
machine, but I'm pretty sure it's more needed in the mythbox, so I plan
to swap them.
> 
> As a side-note, on my machine (X2 3800) I got
> choppy playback if I turn off XvMC and leave bob deinterlace on.  Of
> course, other deint filters might eat less CPU...

Playing video on my desktop (with a 17" monitor connected via VGA),
which currently has the X2 3800, an Nvidia 6800GS and proprietary 8756
Nvidia driver, seems to work fine. Each CPU has 50% or more time free
playing 1080i with Bob. The X process only takes about 10% of a CPU's
time. I'm not entirely sure how to tell if mythfrontend is using XvMC,
just Xv or what. I am using current SVN and selected "Standard" decoder
in the config. Selecting "libmpeg2" decoder uses more CPU time, but
still plays smoothly.

Jonathan Rogers