[FFmpeg-devel] [PATCH 1/6] opus: convert encoder and decoder to lavu/tx

[Martin Storsjö]

On Sat, 24 Sep 2022, Hendrik Leppkes wrote:

> On Sat, Sep 24, 2022 at 9:26 PM Hendrik Leppkes <h.leppkes at gmail.com> wrote:
>>
>> On Sat, Sep 24, 2022 at 8:43 PM Martin Storsjö <martin at martin.st> wrote:
>> >
>> > On Sat, 24 Sep 2022, Lynne wrote:
>> >
>> > > This commit changes both the encoder and decoder to use the new lavu/tx code,
>> > > which has faster C transforms and more assembly optimizations.
>> >
>> > What's the case of e.g. 32 bit arm - that does have a bunch of fft and
>> > mdct assembly, but is that something that ends up used by opus today, or
>> > does the mdct15 stuff use separate codepaths that aren't optimized there
>> > today yet?
>> >
>>
>> mdct15 only has some x86 assembly, nothing for ARM.
>> Only the normal (power of 2) fft/mdct has some ARM 32-bit assembly.
>>
>
> Actually, I missed that the mdct15 internally uses one of the normal
> fft functions for a part of the calculation, but how much impact that
> has on performance vs. the new code where the C alone is quite a bit
> faster would have to be confirmed by Lynne.

Ok, fair enough.

What about ac3dsp then - that one seems like it's fairly optimized for 
arm?

// Martin