[mythtv] MPEG-4 trouble on SMP

Ray mythtv-dev@snowman.net
Wed, 30 Oct 2002 22:34:32 -0700

On Wed, Oct 30, 2002 at 10:35:50PM -0500, Samit Basu wrote:
> Hi -
> I've got a strange problem with mythtv when I use MPEG-4 encoding.
> Recordings work fine, as do playbacks, but when I watch live TV, the video
> is corrupted.  It looks mostly fine, but there are blocking artifacts --
> blocks of color, white and black that fade in and out periodically.  I
> don't have the same problem with rtjpeg, and the problem doesn't go away
> with reduced capture resolution (I tried down to 320 x 200). I'm running
> on a dual 1GHz PIII, and the artifacts go away when I run a non-SMP
> kernel. (hence the subject line)...  I looked at the rwlocks in
> RingBuffer.cpp, but wasn't familiar enough with the code to spot the
> problem (e.g., why is a read-lock used in the Write method?).  Any ideas?

I don't have an answer but I can confirm that I've had the same problem on
my Dual Celeron system.