[FFmpeg-devel] idct/fdct optimizations on arm

[Måns Rullgård]

Pavel Pavlov <pavel at summit-tech.ca> writes:

>> > I read doc/optimization.txt and I have a question.  I'm using h263
>> > video encoder and swscaler to stretch images and I'm kind of low
>> > on CPU power (windows mobile, arm11 cpu). I have some custom code
>> > to use hardware acceleration for idct/fdct. I see there are
>> > optimized version for arm in libavcodec/arm/, so I just wanted to
>> > ask 1) if I can get noticeable improvements in video encoder with
>> > more optimized idct code and 2) if it's easy to do (to hook up
>> > custom functions for that) :)
>> In encoding more time is usually spent in motion search than in
>> (i)dct, but optimising the transforms is still worthwhile.
>
> Motion search, what kind of function are these? I see motion
> estimation mentioned in optimization.txt: pix_abs16x16%%,
> pix_abs8x8%%?

Yes, those would be among them.

>> What hardware do you have with accelerated dct?
>
> I think most mobiles have some sort of HW for that.

Most phones have some kind of video accelerators, usually frame-level
codecs with secret APIs talking to more secret hardware.

You said you had some code to use a hw dct accelerator.  I was curious
what this was.

-- 
M?ns Rullg?rd
mans at mansr.com