[MPlayer-dev-eng] Optimizing mplayer on MIPS

Nicholas Fellows nick at polyprecords.com
Fri Dec 12 21:50:38 CET 2003

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. 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 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. I am quite excited to follow what you are doing, I cant really 
contribute code wise (still learning C) but I am more than willing to do some 
benchmarking on the PS2 if you would like. You might also like to take a look 
at the PS2Reality Player (if you have access to a ps2 kit) I beleive that is 
based on MPlayer, and gives pretty good results (provided the  resolution 
isnt too high). ffmpeg was definitely the way to go audio wise, everything 
else sucked! In short With some tweaking you can get the odd film to play 
perfectly. But most of the stuff I tried was poor to unwatchable. (I am 
convinced this need not be the case!)

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)

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

nick ...

On Friday 12 December 2003 9:20 pm, Josh Green wrote:
> I sent this first to the MPlayer users list, but realized afterward that
> the development list was probably more appropriate. My apologies if this
> is not the proper list for this topic.
> ------------
> I emailed this list a while back concerning running MPlayer on a MIPS
> development board that lacks an FPU. The information I received at the
> time about most video decoders being implemented with integer math
> proved very helpful, and after switching to libmad for integer only MP3
> audio decoding things are much better.
> I'm still running into some performance issues though and I haven't yet
> been able to track down what exactly is causing it. I just recently
> discovered that outputting video to the fbdev takes a huge amount of CPU
> time compared to -vo null. This is probably due to the software scaler
> which is used to do color space conversion (and sometimes aspect ratio
> correction). I've looked briefly over the swscale.c source file and it
> seems there is some usage of doubles in there. I have yet to get a
> profiler working on this system so I'm discovering things somewhat
> blindly at the moment. Does anyone on this list know if there is a
> scaler implemented in integer only math? If anyone has any other tips on
> areas that might be using lots of floating point I would appreciate the
> info. I would also be interested in knowing what kind of performance
> others have been getting with FPU/MMX-less systems.
> Here are some benchmarks I performed if anyone is interested. The
> benchmark.avi is a 640x480 MPEG PES 23.976 fps 1800 kbps file I encoded
> from DIVX to MPEG 1 using mencoder. The test was done on 1200 frames of
> video without sound (which should come out to 50 seconds of wall clock
> video).
> NULL video
> ----------
> mplayer -nosound -benchmark -vo null -frames 1200 benchmark.avi
> BENCHMARKs: VC:   0.063s VO:   0.072s A:   0.000s Sys:   3.515s =
> 3.650s
> BENCHMARK%: VC:  1.7293% VO:  1.9688% A:  0.0000% Sys: 96.3019% =
> 100.0000%
> FBdev video
> -----------
> mplayer -nosound -benchmark -frames 1200 benchmark.avi
> BENCHMARKs: VC:  35.265s VO:  24.540s A:   0.000s Sys:   1.524s =
> 61.329s
> BENCHMARK%: VC: 57.5019% VO: 40.0132% A:  0.0000% Sys:  2.4849% =
> 100.0000%
> So with NULL video it takes 3.65 seconds to decode 50 seconds worth of
> video. With FBdev video output it takes 61.329 seconds! (16.8 times as
> long). Using other codecs like MPEG 4 yield rather poor results with
> this platform, anyone know of some rough minimum specs to decode
> different types of video? Thanks in advance for any advice or
> information. Cheers.
> 	Josh Green
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> MPlayer-dev-eng at mplayerhq.hu
> http://mplayerhq.hu/mailman/listinfo/mplayer-dev-eng

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