[mythtv-users] HD upgrade: new problems with playback

Chris Dos chris at chrisdos.com
Sun Feb 18 01:10:43 UTC 2007


Willy Boyd wrote:
> I recently upgraded my combo backend/frontend to better support HD
> playback.  This is what I'm running now:
> 
> ASUS M2NPV-VM w/ 6150, VGA out (1360x768 res)
> Athlon X2 3800+ (AM2, 65w)
> 1gb DDR-800 ram
> NVIDIA driver 9746
> 
> However the real kicker came when I tried to test HD playback.  I
> don't have an HD tuner yet so for a test I downloaded "Elephant's
> Dream" from orange.blender.org, both the 1080p version and the "1024"
> version.  Both play pretty well with VLC and mplayer (1024 perfectly,
> 1080p with a few drops).  However, neither play at at with the
> Internal player.  I get a black screen and a whole slew of "NVP: Timed
> out waiting for free video buffers" and "NVP::AddAudioData():p1: Audio
> buffer overflow, audio data lost!".  After a few seconds on the "1024"
> video I get what looks like the video playing really fast, but only a
> few frames per second, and really blocky like satellite on a stormy
> day.  Both clips are MPEG4 with AC3 audio.


I built a new frontend for Christmas using the same M2NPV-VM motherboard and Athlon X2
3800+ processor which is running at 2.0 ghz for each core.  I'm using SVN for both my
frontend and combo backend/frontend boxes.  I've been experiencing the same prebuffering
pauses when using either standard or libmpeg2 for playback for HD content.  SD works fine.
 All of this is pulling off my backend.  Now watching top to watch the load, the system is
fully hammering one of the cores.  So my prebuffering pauses are caused by there not being
enough CPU to process the HD signal even though it's a dual core system.  I thought I
built this system powerful enough to playback HD, but it's just not handling it.

I have a combo frontend/backend that has a 4200+ X2 processor with a Nvidia PCIe 7300 LE
graphics card and it can playback HD fine, though it is stressing one of the cores to
around 90%.  But it was around 70% back in August using SVN.  I think sometime between
August and January, CPU usuge for HD playback has gone up.

I tried overclocking the 3800+ to 2.2 ghz, but that didn't seem to fix my problem.  Maybe
I didn't have the right settings for that, so I'm probably going to get that another try
since these chips have the headroom for it.

So my "solution" right now is to use XvMC for HD playback.  And surprisingly, it's working
fine.  It didn't back in July, so that is something SVN has fixed.  I don't want to keep
using XvMC, and I would like to eventually find out what is causing all the prebuffering
pauses.  But I've exhausted all my know how on it at this point.

	Chris


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