Mplayer Development And Optimization For Arm Options

[Serge]

Probably it is a good idea to consolidate efforts and try to submit some of the useful ARM related patches upstream:
http://lists.mplayerhq.hu/pipermail/ffmpeg...ust/014460.html
http://lists.mplayerhq.hu/pipermail/mplaye...ber/046207.html

I can only test MPlayer on Nokia 770, so can't be sure if any ARM9E (that's the core used in Nokia 770) specific optimizations are also good for Zaurus. So people who are able to compile MPlayer from sources and test it on zaurus are welcome in this thread. One of the examples is the new armv5te optimized idct in MPlayer 1.0rc1, can anybody benchmark it on Zaurus?

Also this is not quite ARM architecture related, but libmad based decoder in MPlayer seems to have troubles with variable bitrate audio (it loses sync with video). Some more details can be found here http://lists.mplayerhq.hu/pipermail/mplaye...ust/045017.html and in the followup messages. Any volunteer to investigate this problem?

All in all, ffmpeg optimizations for ARM are not nearly as good as for x86, so investing some time in it may provide some performance improvement.

[Serge]

Just to keep you informed, the work on implementing MPlayer video output driver with hardware YUV support for Nokia 770 is more or less finished. At least it is in usable state now.

But in order to get good performance for any video resolutions, optimized YV12->YUY2 scaler is still needed on Nokia 770. By the way, how does Zaurus handle video scaling? Is it hardware accelerated or a software scaler is used? If it is software scaler, what YUV format is used for output?

Here is some mplayer log console output from Nokia 770 (video is software scaled to 400x210 and then hardware pixel doubling is used to show it fullscreen as 800x420):

CODE

VO: [nokia770] 336x176 => 336x176 Planar YV12 [fs]
SwScaler: reducing / aligning filtersize 2 -> 2
SwScaler: reducing / aligning filtersize 2 -> 2
SwScaler: reducing / aligning filtersize 2 -> 2
SwScaler: reducing / aligning filtersize 2 -> 2

SwScaler: FAST_BILINEAR scaler, from yuv420p to yuyv422 using C
SwScaler: using FAST_BILINEAR C scaler for horizontal scaling
SwScaler: using 2-tap linear C scaler for vertical scaling (BGR)
SwScaler: 336x176 -> 400x210

What do you usually observe on your Zaurus?

[koen]

By the way, how does Zaurus handle video scaling? Is it hardware accelerated or a software scaler is used? If it is software scaler, what YUV format is used for output?

That depends on the models, but basically:

* collie: no acceleration at all
* poodle: ditto
* c7x0: ati imageon w100 which can do limited scaling, YUV transform and idct (http://libw100.sf.net/)
* cxxxx: pxa270fb, which doesn't do scaling AFAIK, but can do YUV transforms and has a small amount of SRAM to do faster blitting when using QVGA.

The cxxx models can also use iwmmxt instructions, but a crude test showed it only gives a ~2% improvement, but there's a lot of room for improvement.
The c7x0 models would benefit from people helping the libw100 project.

[koen]

The cxxx models can also use iwmmxt instructions, but a crude test showed it only gives a ~2% improvement, but there's a lot of room for improvement.
The c7x0 models would benefit from people helping the libw100 project.

'XorA' in #oe on irc.freenode.net is our resident mplayer guru and 'sirfred' the w100 guru.