[MPlayer-dev-eng] mp3 decoding performance on ARM (was: mplayer libtremor patch)

[Michael Niedermayer]

Hi

On Mon, Aug 14, 2006 at 12:43:03AM +0300, Siarhei Siamashka wrote:
> On Sunday 13 August 2006 22:44, Diego Biurrun wrote:
> 
> > Have you tried ffmp3?  The MP3 decoder in FFmpeg is integer-only.  I'd
> > be interested to know how it performs compared to libmad.
> 
> Nokia 770, ARM926EJS 250MHz cpu
> 
> 128kbit constant bitrate soundtrack, length 6:13
> MPlayer 1.0pre8, libmad 0.15.1b
> 
> time ./mplayer -quiet -ac mad -ao pcm:fast:file=/dev/null -vo null -vc null 
> test.mp3
> ...
> real    0m 46.92s
> user    0m 46.22s
> sys     0m 0.50s
> 
> time ./mplayer -quiet -ac ffmp3 -ao pcm:fast:file=/dev/null -vo null -vc null 
> test.mp3
> ...
> real    1m 27.84s
> user    1m 26.91s
> sys     0m 0.64s

please retry this with CONFIG_MPEGAUDIO_HP disabled, and dont forget 
make distclean, also ensure that the decoder uses integers for the antialias
filter, theres also a float version of that ...


> 
> So libmad is still faster, maybe because of ARM assembler optimizations.

very possible


> But I also found the following link which is advertised to have fast fixed
> point mp3 decoder (17MHz for decoding 128kbit soundtrack):
> https://datatype.helixcommunity.org/mp3dec.html
> 
> Using above statistics, libmad cpu requirements estimate is 31MHz, and it is
> somewhat higher than helix decoder advertised numbers. Surely mplayer itself
> adds some overhead in demuxing and buffering, but probably helix decoder is
> worth trying. Now trying to figure out how to get its sources from CVS and 
> what is that RPSL license :-)

something which probably has nothing to do with the word free or open ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is