[MPlayer-dev-eng] [PATCH] correct illegal instruction on < armv5tE

[Siarhei Siamashka]

On Monday 13 October 2008, Gregor Riepl wrote:
> > My device is the openmoko freerunner GTA02.
>
> Won't you run into severe performance issues on that platform?
> The 920T series is not quite lightning fast, so you'd probably need at
> least hardware colorspace transformation and scaling support to
> display anything larger than thumbnail size.

Just FYI, video decoding capabilities limit for Nokia 770 with 926ejs core
running at 252MHz is currently something like this video:
http://samples.mplayerhq.hu/benchmark/testsuite1/matrixbench_normdivx_vbrmp3.avi

There are some frames dropped in heavy action scenes, but overall it is
watchable. Video is decoded on ARM core, audio is offloaded to DSP and has
almost zero overhead, there is hardware YUV support, but scaling is performed
in software. 

Now regarding this freerunner GTA02, it is armv4, but cpu frequency is much
higher and it can probably compensate missing armv5te edsp instructions.
Smaller instructions cache (16K vs. 32K) is a bit worrying, so it might affect
performance and compilation with -O2 or -Os instead of -O3 might be
preferable.

There was also a discussion about video decoding performance on Sharp Zaurus
(PXA270 416MHz, xscale) and it is supposedly quite horrible according to:
http://thread.gmane.org/gmane.linux.distributions.angstrom.user/1583/focus=1645

They suspected that Sharp Zaurus has very bad memory bandwidth performance and
it kills everything. I also tried to take part in that discussion as I was
very curious what exactly could be wrong (Sharp Zaurus seems to be a similar
or better hardware than Nokia 770 as it also has armv5te instructions support
and even iwmmxt, has hardware YUV but also no arbitrary hardware scaling). But
they did not seem to be very motivated to even try benchmarking anything or
accept any help :)

> Is there any progress on that side? From what I've read, the Neo's
> graphics accelerator (Smedia Glamo 3362) is as tightly NDA'd as its
> GSM chip.
> On the other hand, implementing full hardware video acceleration (the
> Glamo can do MPEG4), would be awesome. vaapi has still a long way to
> go, it seems.
>
> But I don't want to criticise your effort, improving compatibility is
> always a good thing.

I think it is not only compatibility, but there is also some quite visible
practical use. For example, flash video was also mentioned and it should 
play just fine on this hardware.

-- 
Best regards,
Siarhei Siamashka