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

[Hendrik Leppkes]

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.

- Hendrik