[MPlayer-dev-eng] [PATCH] Optimized libmpeg2 routines for ARM/Xscale

[Diego Biurrun]

On Sun, May 13, 2007 at 04:16:52PM +0300, Siarhei Siamashka wrote:
> On Tuesday 08 May 2007 00:54, Guillaume POIRIER wrote:
> 
> > > In addition, there is a problem with PLD (cache prefetch) instruction, it
> > > is only available on ARMv5TE, but this code is also getting compiled in
> > > when configured for ARMv4. The same problem exists in ffmpeg as well, and
> > > it was raised on ffmpeg-devel mailing list recently.
> >
> > Fine, but you already have it on your fork!
> 
> What fork? ;-) It's more like a branch. I'm subscribed to both mplayer-dev-eng
> and ffmpeg-developers mailing lists since the very beginning and tracking
> what's happening here related to ARM support. All public MPlayer releases
> get imported into maemo garage SVN and ARM/maemo related improvements 
> are initially developed there. When I consider that something is ready for
> inclusion into the official tree, it gets posted here or in the
> ffmpeg-developers mailing list as a patch.
> 
> Branching only public releases is important to save time and be sure that 
> all the regressions introduced in the sequential maemo builds are only my 
> fault. Everything would become much harder if constantly keeping code in 
> sync with official MPlayer SVN trunk. I'm interested not only in bleeding edge
> features and optimizations (which can be always verified and backported), but
> in having reliable and end user ready packages as well.
> 
> Can you suggest a better development model considering that I usually have
> only a handful hours each week (mostly on weekends) to work on this free
> project?

Become an MPlayer developer with commit privileges.  Many of us do not
really have more time to work on MPlayer than you do.

> > > Would you like to have ARMv5 optimizations [1] merged in MPlayer as well?
> > > I was not sure if it would be a good idea to submit them to MPlayer
> > > instead of upstream libmpeg2, so did not try that earlier.
> > >
> > > 1.
> > > https://garage.maemo.org/plugins/scmsvn/viewcvs.php/trunk/libmpeg2/?root=
> > >mplayer
> >
> > libmpeg2 project doesn't seem too reactive these days. Feel free to
> > send patches to improve libmpeg2 ARM support on MPlayer's fork.
> > I'll do my best to review them and merge them.
> 
> The patch is attached. This code is used in maemo builds since revision 28:
> https://garage.maemo.org/plugins/scmsvn/viewcvs.php?root=mplayer&view=rev&rev=28
> 
> It passed my '-vo md5sum' tests. Also it reduces decoding time to ~105 seconds
> for the video file that was used for older benchmarks:
> http://article.gmane.org/gmane.comp.video.mplayer.devel/43038

What about optimizing FFmpeg instead?  libmpeg2 has been orphaned.  I
don't know about ARM, but FFmpeg should be faster at decoding MPEG-1/2
on x86 and PPC...

Diego