[mythtv] MPEG-4 trouble on SMP

Benjamin Binford mythtv-dev@snowman.net
Thu, 31 Oct 2002 09:03:34 -0500

On Wed, Oct 30, 2002 at 10:34:32PM -0700, Ray wrote:
> 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.

I can also confirm for a dual 800mhz PIII.