[mythtv] testing mythtv-vid branch - questions & problems

Matt Doran matt.doran at papercut.biz
Sat Jun 30 01:38:22 UTC 2007

> This looks like a bug. Could you note this on the #2287
> ticket? Just so it doesn't fall through the cracks..
>> Others have good success with the OpenGL renderer, so I'm wondering what 
>> I'm missing.    I'm using an onboard Nvidia 6150 video board... is this 
>> card powerful enough?  What boards have others had success with?
> I'm using a 6600 GT for testing and it can handle 640x480, you
> need a better card for HDTV resolutions. An on board video card
> that doesn't have it's own high speed memory will probably not
> perform as well as a separate card in most circumstances. While
> it can load the video frames themselves more quickly, it can
> not filter or scale them as quickly. Also, make sure you have
> dual channel memory access enabled for the best performance
> (using matched RAM chips, the BIOS POST will tell you if you
> have dual channel memory access.)
I do have dual channel memory, but I'm in Australia viewing DVB 16:9 
content which is all higher than 640x480 ... so I'm probably asking too 
much of the onboard card.

I managed to get my hands on a nvidia 7600gs, and it performed much 
better.... even enabling opengl vsync worked.  On the 6150, opengl vsync 
caused all kinds of odd problems.

Although I only tested the 7600gs for an hour or two, I found it to be 
less stable.   Sometimes it would crash, other when I started playback 
it would just pause for 1-2 secs play a few frames, pause again, play a 
few frames, over and over.  If I stopped an restarted the playback it 
would fix itself up.   So the stability just doesn't appear to be there 
yet .... but maybe it's the drivers I'm using??

Does you know what video card would be required to render 1080i content, 
and deinterlace it?     The nvidia purevideo drivers can do this easily 
on pretty average hardware.... but I'm not sure how that compares to how 
mythtv opengl rendering compares.
>> I'm using version 9631 of the nvidia drivers, and a fairly standard 
>> Ubuntu Feisty system (AMD X2 3600+, 1GB RAM).
> 7667 seems to be the most stable release. Aside from some
> limited tearing issues, 8776 works for me. The 9xxx drivers no
> longer cause segfaults, but I wouldn't recommend them either.
It's  pretty disappointing that the nvidia drivers are so 
inconsistent.    Is there any information out there to provide 
recommendations on the best version to use ... e.g. listing known 
problems with each?    I've looked but the information is hard to come by.
> -- Daniel
> BTW Make sure you restore your DB after testing, the mythtv-vid
>     branch does change the DB & DB schema revision number.
I noticed that it only added 2 tables, so I could just drop those and 
decrement the DBSchemaVer setting if I wanted to move back to trunk, right?


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