[FFmpeg-devel] [PATCH v2 07/13] avfilter/x86/f_ebur128: add x86 AVX implementation
Niklas Haas
ffmpeg at haasn.xyz
Mon Jun 16 14:15:22 EEST 2025
On Fri, 13 Jun 2025 22:20:03 -0300 James Almer <jamrial-at-gmail.com at ffmpeg.org> wrote:
> On 6/13/2025 1:37 PM, Niklas Haas wrote:
> > From: Niklas Haas <git at haasn.dev>
> >
> > Processes two channels in parallel, using 128-bit XMM registers.
> >
> > In theory, we could go up to YMM registers to process 4 channels, but this is
> > not a gain except for relatively high channel counts (e.g. 7.1), and also
> > complicates the sample load/store operations considerably.
> >
> > I decided to only add an AVX variant, since the C code is not substantially
> > slower enough to justify a separate function just for ancient CPUs.
> > ---
> > libavfilter/f_ebur128.c | 15 ++--
> > libavfilter/f_ebur128.h | 16 ++++
> > libavfilter/x86/Makefile | 2 +
> > libavfilter/x86/f_ebur128.asm | 142 +++++++++++++++++++++++++++++++
> > libavfilter/x86/f_ebur128_init.c | 35 ++++++++
> > 5 files changed, 205 insertions(+), 5 deletions(-)
> > create mode 100644 libavfilter/x86/f_ebur128.asm
> > create mode 100644 libavfilter/x86/f_ebur128_init.c
> >
> > diff --git a/libavfilter/f_ebur128.c b/libavfilter/f_ebur128.c
> > index b9e210c05a..2d94cefce7 100644
> > --- a/libavfilter/f_ebur128.c
> > +++ b/libavfilter/f_ebur128.c
> > @@ -579,6 +579,11 @@ static av_cold int init(AVFilterContext *ctx)
> > /* summary */
> > av_log(ctx, AV_LOG_VERBOSE, "EBU +%d scale\n", ebur128->meter);
> >
> > + ebur128->dsp.filter_channels = ff_ebur128_filter_channels_c;
> > +#if ARCH_X86
> > + ff_ebur128_init_x86(&ebur128->dsp);
> > +#endif
> > +
> > return 0;
> > }
> >
> > @@ -692,11 +697,11 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
> > MOVE_TO_NEXT_CACHED_ENTRY(400);
> > MOVE_TO_NEXT_CACHED_ENTRY(3000);
> >
> > - ff_ebur128_filter_channels_c(dsp, &samples[idx_insample * nb_channels],
> > - &ebur128->i400.cache[bin_id_400 * nb_channels],
> > - &ebur128->i3000.cache[bin_id_3000 * nb_channels],
> > - ebur128->i400.sum, ebur128->i3000.sum,
> > - nb_channels);
> > + dsp->filter_channels(dsp, &samples[idx_insample * nb_channels],
> > + &ebur128->i400.cache[bin_id_400 * nb_channels],
> > + &ebur128->i3000.cache[bin_id_3000 * nb_channels],
> > + ebur128->i400.sum, ebur128->i3000.sum,
> > + nb_channels);
> >
> > #define FIND_PEAK(global, sp, ptype) do { \
> > int ch; \
> > diff --git a/libavfilter/f_ebur128.h b/libavfilter/f_ebur128.h
> > index dfc2e7c75b..decf3917af 100644
> > --- a/libavfilter/f_ebur128.h
> > +++ b/libavfilter/f_ebur128.h
> > @@ -19,6 +19,9 @@
> > * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> > */
> >
> > +#include <assert.h>
> > +#include <stddef.h>
> > +
> > typedef struct EBUR128Biquad {
> > double b0, b1, b2;
> > double a1, a2;
> > @@ -32,7 +35,20 @@ typedef struct EBUR128DSPContext {
> > /* Cache of 3 samples for each channel */
> > double *y; /* after pre-filter */
> > double *z; /* after RLB-filter */
> > +
> > + /* DSP functions */
> > + void (*filter_channels)(const struct EBUR128DSPContext *dsp,
> > + const double *samples,
> > + double *cache_400, double *cache_3000,
> > + double *sum_400, double *sum_3000,
> > + int nb_channels);
> > } EBUR128DSPContext;
> >
> > +static_assert(offsetof(EBUR128DSPContext, pre) == 0, "struct layout mismatch");
> > +static_assert(offsetof(EBUR128DSPContext, rlb) == 5 * sizeof(double), "struct layout mismatch");
> > +static_assert(offsetof(EBUR128DSPContext, y) == 10 * sizeof(double), "struct layout mismatch");
> > +
> > +void ff_ebur128_init_x86(EBUR128DSPContext *dsp);
> > +
> > void ff_ebur128_filter_channels_c(const EBUR128DSPContext *, const double *,
> > double *, double *, double *, double *, int);
> > diff --git a/libavfilter/x86/Makefile b/libavfilter/x86/Makefile
> > index 0d9a28a935..0efe3f8d2c 100644
> > --- a/libavfilter/x86/Makefile
> > +++ b/libavfilter/x86/Makefile
> > @@ -7,6 +7,7 @@ OBJS-$(CONFIG_BLEND_FILTER) += x86/vf_blend_init.o
> > OBJS-$(CONFIG_BWDIF_FILTER) += x86/vf_bwdif_init.o
> > OBJS-$(CONFIG_COLORSPACE_FILTER) += x86/colorspacedsp_init.o
> > OBJS-$(CONFIG_CONVOLUTION_FILTER) += x86/vf_convolution_init.o
> > +OBJS-$(CONFIG_EBUR128_FILTER) += x86/f_ebur128_init.o
> > OBJS-$(CONFIG_EQ_FILTER) += x86/vf_eq_init.o
> > OBJS-$(CONFIG_FSPP_FILTER) += x86/vf_fspp_init.o
> > OBJS-$(CONFIG_GBLUR_FILTER) += x86/vf_gblur_init.o
> > @@ -52,6 +53,7 @@ X86ASM-OBJS-$(CONFIG_BLEND_FILTER) += x86/vf_blend.o
> > X86ASM-OBJS-$(CONFIG_BWDIF_FILTER) += x86/vf_bwdif.o
> > X86ASM-OBJS-$(CONFIG_COLORSPACE_FILTER) += x86/colorspacedsp.o
> > X86ASM-OBJS-$(CONFIG_CONVOLUTION_FILTER) += x86/vf_convolution.o
> > +X86ASM-OBJS-$(CONFIG_EBUR128_FILTER) += x86/f_ebur128.o
> > X86ASM-OBJS-$(CONFIG_EQ_FILTER) += x86/vf_eq.o
> > X86ASM-OBJS-$(CONFIG_FRAMERATE_FILTER) += x86/vf_framerate.o
> > X86ASM-OBJS-$(CONFIG_FSPP_FILTER) += x86/vf_fspp.o
> > diff --git a/libavfilter/x86/f_ebur128.asm b/libavfilter/x86/f_ebur128.asm
> > new file mode 100644
> > index 0000000000..28add77f70
> > --- /dev/null
> > +++ b/libavfilter/x86/f_ebur128.asm
> > @@ -0,0 +1,142 @@
> > +;*****************************************************************************
> > +;* x86-optimized functions for overlay filter
> > +;*
> > +;* Copyright (C) 2018 Paul B Mahol
> > +;* Copyright (C) 2018 Henrik Gramner
> > +;*
> > +;* 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 "libavutil/x86/x86util.asm"
> > +
> > +cextern ebur128_filter_channels_c
> > +
> > +struc Biquad
> > + .b0 resq 1
> > + .b1 resq 1
> > + .b2 resq 1
> > + .a1 resq 1
> > + .a2 resq 1
> > +endstruc
> > +
> > +struc DSP
> > + .pre resq 5
> > + .rlb resq 5
> > + .y resq 1
> > + .z resq 1
> > +endstruc
> > +
> > +SECTION .text
> > +
> > +%macro MOVNQ 3 ; num, dst, src
> > +%if %1 == 1
> > + movsd %2, %3
> > +%else
> > + movupd %2, %3
> > +%endif
> > +%endmacro
> > +
> > +%macro FILTER 11 ; y0, y1, y2, x, b0, b1, b2, a1, a2, samples, num_channels
> > + ; Y[0] := b0 * X + Y1
> > + ; Y[1] := b1 * X + Y2 - a1 * Y[0]
> > + ; Y[2] := b2 * X - a2 * Y[0]
> > + movsd %1, [%10 + 8]
> > + movsd %3, [%10 + 16]
> > +%if %11 > 1
> > + movhpd %1, [%10 + 32]
> > + movhpd %3, [%10 + 40]
> > +%endif
> > +
> > + mulpd %2, %5, %4
> > + addpd %1, %2
> > +
> > + mulpd %2, %8, %1
> > + subpd %3, %2
> > + mulpd %2, %6, %4
> > + addpd %2, %3
> > +
> > + mulpd %3, %7, %4
> > + mulpd %4, %9, %1
> > + subpd %3, %4
> > +
> > + movlpd [%10 + 0], %1
> > + movlpd [%10 + 8], %2
> > + movlpd [%10 + 16], %3
>
> movsd?
Changed.
>
> > +%if %11 > 1
> > + movhpd [%10 + 24], %1
> > + movhpd [%10 + 32], %2
> > + movhpd [%10 + 40], %3
> > +%endif
> > + add %10, 24 * %11
> > +%endmacro
> > +
> > +%macro filter_channels 1 ; num_channels
> > + MOVNQ %1, m3, [samplesq]
> > + add samplesq, 8 * %1
> > +
> > + FILTER m0, m1, m2, m3, m4, m5, m6, m7, m8, r7q, %1
> > + FILTER m3, m1, m2, m0, m9, m10, m11, m12, m13, r8q, %1
> > +
> > + ; update sum and cache
> > + mulpd m3, m3
> > + subpd m0, m3, [cache400q]
> > + subpd m1, m3, [cache3000q]
> > + MOVNQ %1, [cache400q], m3
> > + MOVNQ %1, [cache3000q], m3
> > + add cache400q, 8 * %1
> > + add cache3000q, 8 * %1
> > + addpd m0, [sum400q]
> > + addpd m1, [sum3000q]
> > + MOVNQ %1, [sum400q], m0
> > + MOVNQ %1, [sum3000q], m1
> > + add sum400q, 8 * %1
> > + add sum3000q, 8 * %1
> > +%endmacro
> > +
> > +INIT_XMM avx
> > +cglobal ebur128_filter_channels, 7, 9, 14, dsp, samples, cache400, cache3000, sum400, sum3000, channels
> > + vpbroadcastq m4, [dspq + DSP.pre + Biquad.b0]
>
> vpbroadcastq is AVX2, not AVX. Use movddup instead.
Fixed.
>
> > + vpbroadcastq m5, [dspq + DSP.pre + Biquad.b1]
> > + vpbroadcastq m6, [dspq + DSP.pre + Biquad.b2]
> > + vpbroadcastq m7, [dspq + DSP.pre + Biquad.a1]
> > + vpbroadcastq m8, [dspq + DSP.pre + Biquad.a2]
> > +
> > + vpbroadcastq m9, [dspq + DSP.rlb + Biquad.b0]
> > + vpbroadcastq m10, [dspq + DSP.rlb + Biquad.b1]
> > + vpbroadcastq m11, [dspq + DSP.rlb + Biquad.b2]
> > + vpbroadcastq m12, [dspq + DSP.rlb + Biquad.a1]
> > + vpbroadcastq m13, [dspq + DSP.rlb + Biquad.a2]
> > +
> > + mov r7q, [dspq + DSP.y]
> > + mov r8q, [dspq + DSP.z]
> > +
> > + ; handle odd channel count
> > + test channelsd, 1
> > + jnz .tail
> > +
> > +.loop:
> > + filter_channels 2
> > + sub channelsd, 2
> > + jg .loop
> > + RET
> > +
> > +.tail:
> > + filter_channels 1
> > + dec channelsd
> > + test channelsd, channelsd
> > + jnz .loop
> > + RET
> > diff --git a/libavfilter/x86/f_ebur128_init.c b/libavfilter/x86/f_ebur128_init.c
> > new file mode 100644
> > index 0000000000..c5edfde03a
> > --- /dev/null
> > +++ b/libavfilter/x86/f_ebur128_init.c
> > @@ -0,0 +1,35 @@
> > +/*
> > + * Copyright (c) 2018 Paul B Mahol
> > + *
> > + * 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 "libavutil/attributes.h"
> > +#include "libavutil/cpu.h"
> > +#include "libavutil/x86/cpu.h"
> > +#include "libavfilter/f_ebur128.h"
> > +
> > +void ff_ebur128_filter_channels_avx(const EBUR128DSPContext *, const double *,
> > + double *, double *, double *, double *, int);
> > +
> > +av_cold void ff_ebur128_init_x86(EBUR128DSPContext *dsp)
> > +{
> > + int cpu_flags = av_get_cpu_flags();
> > +
> > + if (EXTERNAL_AVX(cpu_flags))
> > + dsp->filter_channels = ff_ebur128_filter_channels_avx;
> > +}
>
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