[Libva] Image size restrictions for decode: Samples

[Xiang, Haihao]

> Here's a few sample files I have tried playing with mplayer-vaapi.
> 
> It is an excerpt from "Sintel", a movie by the Blender Institute, scaled 
> to different resolutions.
> 
> http://www.vtnd.de/Intel-samples/1920x1080_HD.mkv
> Standard HD resolution, plays fine via xv, gl and vaapi
> 
> http://www.vtnd.de/Intel-samples/1600x1200_UXGA.mkv
> Plays fine via xv, gl and vaapi
> 
> http://www.vtnd.de/Intel-samples/2048x1536_QXGA.mkv
> Plays fine on xv and gl. Shows strong artifacts on vaapi
> 
> http://www.vtnd.de/Intel-samples/1920_square.mkv
> Plays fine on xv and gl. Very heavy artifacts on vaapi
> 
> http://www.vtnd.de/Intel-samples/2560x1440_QWHD.mkv
> http://www.vtnd.de/Intel-samples/2560x2048_QSXGA.mkv
> Both play fine on gl. Message from xv: no dimension can be beyond 2048. 
> No picture and no message from vaapi
> 
> http://www.vtnd.de/Intel-samples/1920x2206_pseudo-framepack.mkv
> Plays fine on gl.
> Message from xv: no dimension can be beyond 2048.
> Trying to play via vaapi crashes MPlayer
> 

Are you using master branch ? I can't reproduce the issue against master
branch. 

Note the driver doesn't support resolution bigger than 2048x2048 on
sandybridge. Mplayer-vaapi will output the following message then switch
to software decoding for unsupported resolution. It still uses VA API to
display the decoded surface.

======
...
VO: [vaapi] 2560x2048 => 2560x2048 H.264 VA-API Acceleration 
[vo_vaapi] vaCreateContext(): resolution not supported
FATAL: Cannot initialize video driver.
...

VO: [vaapi] 2560x2048 => 2560x2048 Planar YV12 
V:  17.8   0/  0 63% 35%  0.0% 0 0 

Thanks
Haihao