[maemo-developers] N800 & Video playback

[From: Siarhei Siamashka]

On Tuesday 01 May 2007 20:49, Siarhei Siamashka wrote:

Looks like I have to reply to myself.

> On Tuesday 01 May 2007 17:49, Kalle Vahlman wrote:
> > Applied and build without problems for me.
>
> Thanks a lot for building the package and putting it for download,
> everything seems to be fine, but more details will follow below.

[snip]

> Anyway, the new xserver package works really good. If we do some tests with
> the standard Nokia_N800.avi video clip, we get the following results with
> the patched xserver:
>
> #  mplayer -benchmark -quiet -noaspect Nokia_N800.avi
> BENCHMARKs: VC:  29,764s VO:   7,666s A:   0,468s Sys:  64,635s =  102,534s
> BENCHMARK%: VC: 29,0287% VO:  7,4767% A:  0,4565% Sys: 63,0381% = 100,0000%
> BENCHMARKn: disp: 2504 (24,42 fps)  drop: 0 (0%)  total: 2504 (24,42 fps)
>
> #  mplayer -benchmark -quiet -noaspect -dr -nomenu Nokia_N800.avi
> BENCHMARKs: VC:  30,266s VO:   5,490s A:   0,467s Sys:  66,286s =  102,509s
> BENCHMARK%: VC: 29,5255% VO:  5,3554% A:  0,4560% Sys: 64,6631% = 100,0000%
> BENCHMARKn: disp: 2501 (24,40 fps)  drop: 0 (0%)  total: 2501 (24,40 fps)
>
> Results with unpatched xserver and some more explanations can be found in
> [3]. 
> Yes, now N800 is faster than Nokia 770 for video output performance at 
> last :)

Well, still not everything is so good until the following bug gets fixed:
https://maemo.org/bugzilla/show_bug.cgi?id=1281

The patch for optimized Xv performance will not help to watch widescreen
video which triggers this tearing bug. If you see tearing on the screen, you
should know that the YUV420 color format conversion optimization patch 
does not  get used at all and xserver most likely uses a slow nonoptimized
YUV422 fallback code with software scaling.

Fixing this bug is critical for video playback performance. I hope it will be
solved in the next version of N800 firmware too. But it we get some patch to
solve this problem for testing earlir, that would be nice too.

> Video output overhead on N800 is really at least halved. Of course, video
> output takes only some fraction of time in video player. So overall
> performance improvement for Nokia_N800.avi playback is approximately 20%
> but not 250%-300% which can be observed for  'omapCopyPlanarDataYUV420'
> function alone.

Before anybody noticed, correcting myself :) This 'omapCopyPlanarDataYUV420'
has 2.5x-3x improvement which is equal to 150%-200% in percents. Elementary
arithmetics is tough when you are tired