[mythtv-users] Watching HD streams on a SD set

[Enigma]

>  From the man page for the i810 driver:
> Option "XvMCSurfaces" "integer"
> This option enables XvMC. The integer parameter specifies the
> number of surfaces to use. Valid values are 6 and 7. Default:
> XvMC is disabled.
>
> Now I notice that the Xorg.0.log says something to the effect that the
> XvMCSurfaces line is ignored, and then the i810 driver seems to use 
> xvmc...
> However, on my box, I have now noticed that if I re-boot (which I try
> not to do, but this is a new buildup) the Xserver sometime does not
> start, and the system creates a new xorg.conf *using the intel driver*.
> Same Option line is required for that driver, plus 'Option "LinearAlloc"
> "6144" for HD. The intel driver works on my box, but it is using ffmpeg
> decoding. From Xorg.0.log:
>
> 2007-10-03 22:19:19.167 VideoOutputXv Error: XvMC output requested, but
> is not supported by display.
> Xlib: extension "XVideo-MotionCompensation" missing on display ":0.0".
> 2007-10-03 22:19:19.168 XvMCSurfaceTypes::find(w 1280, h 720, chroma 1,
> vld 0, idct 1, mpeg2, sub-width 0, sub-height 0, disp, p<= 88, 730 <=p,
> port, surfNum)
> 2007-10-03 22:19:19.168 Trying XvMC port 73
> ....
>
> So maybe *both* of them don't do xvmc? That is clearly not correct, so
> something is going on...And the mythbox still records, and plays, so I'm
> not touching it until the weekend!
>
> Geoff

Yeah, I quickly found out that XvMC doesn't seem to work with this 
chipset.  Upon closer inspection of the manual the 'XvMCSurfaces' option 
is listed under the section that says "The following driver Options are 
supported for the i810 and i815 chipsets:".  Since this frontend has a 
915G chipset it appears that I am SOL for XvMC.

I am still using the 1.x version (i810) of the driver rather than the 
brand-new 2.x (renamed intel) version.  The main advantage of the new 
driver seems to be the ability to use non-BIOS resolutions and since I 
just use a standard resolution and from your description it sounds like 
it doesn't do XvMC I will probably just continue to use my current 
driver.  I have played around with the various deinterlacing options and 
I am getting much better video quality than before.  It appears that I 
need to deinterlace the HD stream before it is interlaced and sent to my 
TV.  My CPU seems to be able to handle the playback and deinterlacing so 
I probably don't have to have XvMC although if I did it might help me to 
use BOB deinterlacing. 

When I first tested this machine for HD I ran into the 'badalloc' error 
and googled a solution and set LinearAlloc to 8192.  When I was reading 
the manual pages today I saw the line recommending 6144 and so I changed 
my xorg.conf to that value.  This caused my machine to lock up HARD with 
nasty things happening to my display when I attempted to view HD 
content.  Changing the value back to 8192 fixed the problem. 


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