FFmpeg/libavcodec/riscv/opusdsp_init.c
Rémi Denis-Courmont bfc69297c5 lavc/opusdsp: RISC-V V (512-bit) postfilter
This adds a variant of the postfilter for use with 512-bit vectors.
Half a vector is enough to perform the scalar product. Normally a whole
vector would be used anyhow. Indeed fractional multiplers are no faster
than the unit multipler.

But in this particular function, a full vector makes up 16 samples,
which would be loaded at each iteration of the outer loop. The minimum
guaranteed CELT postfilter period is only 15. Accounting for the edges,
we can only safely preload up to 13 samples.

The fractional multipler is thus used to cap the selected vector length
to a safe value of 8 elements or 256 bits.

Likewise, we have the 1024-bit variant with the quarter multipler. In
theory, a 2048-bit one would be possible with the eigth multipler, but
that length is not even defined in the specifications as of yet, nor is
it supported by any emulator - forget actual hardware.
2022-10-10 02:23:17 +02:00

55 lines
1.8 KiB
C

/*
* Copyright © 2022 Rémi Denis-Courmont.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "config.h"
#include "libavutil/attributes.h"
#include "libavutil/cpu.h"
#include "libavutil/riscv/cpu.h"
#include "libavcodec/opusdsp.h"
void ff_opus_postfilter_rvv_128(float *data, int period, float *g, int len);
void ff_opus_postfilter_rvv_256(float *data, int period, float *g, int len);
void ff_opus_postfilter_rvv_512(float *data, int period, float *g, int len);
void ff_opus_postfilter_rvv_1024(float *data, int period, float *g, int len);
av_cold void ff_opus_dsp_init_riscv(OpusDSP *d)
{
#if HAVE_RVV
int flags = av_get_cpu_flags();
if (flags & AV_CPU_FLAG_RVV_F32)
switch (ff_get_rv_vlenb()) {
case 16:
d->postfilter = ff_opus_postfilter_rvv_128;
break;
case 32:
d->postfilter = ff_opus_postfilter_rvv_256;
break;
case 64:
d->postfilter = ff_opus_postfilter_rvv_512;
break;
case 128:
d->postfilter = ff_opus_postfilter_rvv_512;
break;
}
#endif
}