[opus] 2 patches related to silk_biquad_alt() optimization

[Linfeng Zhang]

Hi Jean-Marc,

Tested on my chromebook, when stride (channel) == 1, the optimization has
no gain compared with C function.
When stride (channel) == 2, the optimization is 1.2%-1.8% faster (1.6% at
Complexity 8) compared with C function.

Please let me know and I can remove the optimization of stride 1 case.

If it's allowed to skip the split of A_Q28 and replace by 32-bit
multiplication (result is 64-bit), probably it could be faster on NEON.
This may change the encoder results because of different order of adding,
shifting and rounding.

Thanks,
Linfeng


On Wed, Apr 19, 2017 at 10:23 PM, Jean-Marc Valin <jmvalin at jmvalin.ca>
wrote:

> Hi Linfeng,
>
> Thanks for the patches. I'll have a look and get back to you. What kind
> of speedup are you getting for these functions? On what command line?
>
> Cheers,
>
>         Jean-Marc
>
> On 19/04/17 12:29 PM, Linfeng Zhang wrote:
> > Hi,
> >
> > Attached are 2 patches related to silk_biquad_alt() optimization. Please
> > review.
> >
> > Thanks,
> > Linfeng Zhang
> >
> >
> >
> > _______________________________________________
> > opus mailing list
> > opus at xiph.org
> > http://lists.xiph.org/mailman/listinfo/opus
> >
>
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