[MPlayer-dev-eng] Optimizing mplayer on MIPS

Josh Green jgreen at users.sourceforge.net
Fri Dec 12 23:58:26 CET 2003

On Fri, 2003-12-12 at 12:50, Nicholas Fellows wrote:
> What speed is the MIPS board you are using ?
> I've done a few tests with MPlayer with Playstation 2 which is also mips
> I think the PS2 is 333mhz.

Our current board is just under 400mhz.

> I got some mixed results , I actually found that 
> movies (regardless of codec) tended to run better if their soundtrack 
> was encoded as MP2. most movies ran fine if you disabled the sound completely.

I don't know anything about the PS2, but if it doesn't have a FPU the
default MPlayer MP3 decoder kills throughput, using libmad causes fairly
negligible CPU usage.

> I am assuming that Mplayer is just using the raw Mips chip and not taking 
> advantage of any of the PS2's built in hardware, as it can quite obviously 
> cope with full frame rate video. I also seem to remember, although my memory 
> is a little thin right now, that the sdl or xv outputs seemed to give the 
> best results.

Unfortunately there is no acceleration hardware on this device. So
essentially the frame buffer device is the only option currently (xv
only makes sense if you have YUV scaling hardware acceleration). I
think, as D Richard Felker III mentioned, this is probably causing most
of the performance issues. I suppose the only option from here is to get
accelerated hardware, faster CPU (probably not the best idea) or try and
do some MIPS optimized assembler for the colorspace conversion and
scaling. I would like to get a profiler working though, to get an idea
of what really is causing the bottleneck.

> I have some avi's of the Andromeda Strain which play perfectly on PS2 with the 
> right command line parameters. 
> Spec of the file as follows
> Forced NON-INTERLEAVED AVI file format.
> VIDEO:  [DIV3]  608x320  24bpp  23.98 fps  1194.7 kbps (145.8 kbyte/s)

Thats higher than anything I have gotten to play in real time. I can get
352x240 MPEG 1 files to play, much higher than that and audio/video
loses sync badly and video is real slow. Most of the benchmarking I have
done is with sound disabled. MPEG 4 DIVX files also tend to be much more
CPU hungry then MPEG, which I suppose is to be expected. Its starting to
look like this board just doesn't have the beans to cut it.

> I should really give you some better info than that, but my ps2 is inaccesible 
> at the moment (TV in use!)
> nick ...

Nice to hear about other experiences with MIPS and mplayer, thanks.

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