[mythtv-users] Playback vid corruption with HD NBC (1080i or amd64 related?)

gad at jetcom.org gad at jetcom.org
Tue Jun 14 18:16:41 UTC 2005

I've been seeing a problem for a while now, that has stumped me.

  I see wierd horizontal striping every 1/2 an inch or so.  There is a 
jagged green area on the left (and covering parts of the picture). It 
sort of makes the picture shimmer. It's semi-watchable if you can 
ignore the effect (aka it doens't obstruct the picture)

  This only appears on my NBC broadcasts (and PBS too i think). I think 
this means it's on 1080i broadcasts.  Fox & ABC are crystal clear. I 
don't get CBS right now. I believe that it also appears on upconvered 
material, ie the news was the same way last night.  I only see it on 
one of my frontend which happens to have an amd64 using 64bit gentoo.  
So I'm assuming that it has something to do with that. I'm also 
assuming that it's related to the fact that he signal is interlaced. 
The recording itself is fine, ie I can play it upstairs on a different 

The machine is an AMD64 3500+, nvidia fx5300 connected DVI to a 2005FPW 
flat panel.  I have also had this problem connected to a 50+ rp-lcd tv. 
I have tried various combinations of opengl vsync and various deints 
(kernel/bob). Not using xvmc (never got it to work on this machine), 
processor utilization is ~50-60%.

This *has* worked beautifully before. I don't know why/how it has 
changed.  At one point I believed that it was mmx related, but now it 
seems to be independent. I have tried actively disabling mmx in the 
config. The only thing this now accomplishes is to increase my cpu util 
 > 90-100%. I've seen this effect using various cvs builds on this 
machine since before 0.18

This is different than the problem that I have with the bob deint. With 
that the  SD stuff will shimmer. I haven't seen a fix for that one 
either.  I believe that is also amd64 related.

  It hasn't been a big issue, since i don't watch much on there; but 
I'd like to figure it out, especially before I build anymore amd64 

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