[mythtv-users] CBS HD content suddenly doesn't play

Brad Templeton brad+myth at templetons.com
Fri Feb 13 20:04:11 UTC 2009


On Fri, Feb 13, 2009 at 09:12:17AM -0500, Matthew Zimmerman wrote:
> I've been having the same errors with CBS shows.  Not using xvmc in
> the frontend plays them fine (with some skipping, not enough power!).
> I've been transcoding them and then they'll play just fine.  If anyone
> working on this issue wants specific output, just let me know and I'll
> record another CBS show ;)
> 

This shows up a danger in moving to hardware based decoding.  Back
when I first built my myth machines, long ago, xvmc was not very
stable and had a sucky OSD, and it was just less headache to buy
enough CPU power to decode 1080i.  (Though sadly this was not
enough to always decode 1080 line h264, but of course xvmc doesn't
help with that either.)

Now we're all excited about vdpau, and I have to wonder if we won't
find instances in the future where stations and encoders tweak their
streams in some slightly nonstandard way that makes the hardware
decode unworkable.

Mind you, today you can get a fast dual-core machine able to do all
the HD formats readily for peanuts.  It's hard not to get something
that fast in any new machine.   Older AGP machines can't use the
new GPUs anyway.   GPU decoding is good for CPU offload (saving
CPU for commercial detect and transcode and the rest) so it's not
bad, but it might be risky to build a system without enough CPU
to play the video if the GPU can't handle it.  If another codec
comes along,  you will be screwed, as xvmc users are screwed with
mp4.


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