[Mplayer-dev-eng] [Experimental PATCH] downmix_3dnow.S

Arpi arpi at thot.banki.hu
Sat May 12 17:52:40 CEST 2001


Hi,

> >> >for testing, you can download movie trailer vobs (50-100 mb each) from
> >> >the net, they usually have ac3 audio.
> >> >
> >> >for example:
> >> >http://dvd.index.hu/index.php?show=download&subcat=7
> >> >
> >> Oh thanks ;( !!!
> >> 
> >> >i want to test it, but i have no AMD cpu at all :)
> >> >what about SSE support?
> >> >
> >> SSE support already exists in libac3. For detail see main/libac3/downmix/downmix_kni.S
> >Downmix is just a small part of decoding.. btw, at least on my celeronII,
> >that kni code is exactly as fast as the 586 asm code.
> >(but about 3% faster than .c version)
> >
> I know it. There are a tons of pure C code in time-critical imdct.c+srfft.c+...
> But I still have no ac3 samples - may be later, I hope.
> What you think about adding to mplayer possibility to playback a pure
> audio streams (like mp3, ac3 and so on)? Such feature could make optimization
> easy on top small samples.
I'm already working on this. It requires for .wma playback too.

> And in this case mplayer could be renamed to 'media player for linux' or "multimedia player for linux" ;-) 
Or 'every media player for linux' :)

> And last moment: Mplayer has imported libraries such as (libmp3, libac3, ...). They probably have
> own centres of development. Did you ask their authors about expanding mmx-optimized code?
> And how you plan to synchronize those projects later?
mp3lib is my stuff, i made it for my own mp3 player about 2 year ago,
and still using it for our 3d demo engine too.
it's synced with latest mpg123 version. i dunno that mpg123 is still developed,
but i think it isn't.

libac3 is much interesting. it has some newer version, but they are
incompatible with the old (used by mplayer), and it's a hard work at every
sync to change it.
(new version uses callback for playback instead of stream reading)

I'm usually sync
- loader: mereg from avifile-CVS after big changes
- libmpeg2: after every stable release or interesting changes
- opendivx encore/decore: -''-

> P.S.: Mplayer (and its imported parts) contains a places which can be optimized with using inline-assembler.
> Does mplayer run on non Intel architectures (at least with code which not required win32.dll)?
No. And it wasn't planned to be portable. I think that mpg12player should be
ported if someone interested. it's the parent of mplayer, and supports mpeg
1/2 playback only.

> It would be better to add in mplayer something like HAVE_IA32 and HAVE_CPU=3(4,5,6) to enable such
> assembler optimization. HAVE_CPU or likewise should be numeric for
> #if HAVE_CPU > 3 constructions.
> May you have any ideas about names such macros. (For compatibility with further importing, addition and 
> synchronizing)
Good idea.

> P.P.S.: I'm very interesting with results of downmix_3dnow testing.
I'm too.


A'rpi / Astral & ESP-team

--
mailto:arpi at thot.banki.hu
http://esp-team.scene.hu

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