[FFmpeg-devel] [PATCH v4] mdct15: add assembly optimizations for the 15-point FFT
Rostislav Pehlivanov
atomnuker at gmail.com
Fri Jun 23 04:51:37 EEST 2017
c: 1802 decicycles in fft15,16774635 runs, 2581 skips
avx: 865 decicycles in fft15,16776378 runs, 838 skips
Signed-off-by: Rostislav Pehlivanov <atomnuker at gmail.com>
---
libavcodec/mdct15.c | 182 +++++++++++++++++++++----------------------
libavcodec/mdct15.h | 26 +++----
libavcodec/x86/Makefile | 2 +
libavcodec/x86/mdct15.asm | 137 ++++++++++++++++++++++++++++++++
libavcodec/x86/mdct15_init.c | 95 ++++++++++++++++++++++
5 files changed, 333 insertions(+), 109 deletions(-)
create mode 100644 libavcodec/x86/mdct15.asm
create mode 100644 libavcodec/x86/mdct15_init.c
diff --git a/libavcodec/mdct15.c b/libavcodec/mdct15.c
index 8c42ece483..f93881fbed 100644
--- a/libavcodec/mdct15.c
+++ b/libavcodec/mdct15.c
@@ -57,11 +57,6 @@ av_cold void ff_mdct15_uninit(MDCT15Context **ps)
av_freep(ps);
}
-static void mdct15(MDCT15Context *s, float *dst, const float *src, ptrdiff_t stride);
-
-static void imdct15_half(MDCT15Context *s, float *dst, const float *src,
- ptrdiff_t stride, float scale);
-
static inline int init_pfa_reindex_tabs(MDCT15Context *s)
{
int i, j;
@@ -93,88 +88,8 @@ static inline int init_pfa_reindex_tabs(MDCT15Context *s)
return 0;
}
-av_cold int ff_mdct15_init(MDCT15Context **ps, int inverse, int N, double scale)
-{
- MDCT15Context *s;
- double alpha, theta;
- int len2 = 15 * (1 << N);
- int len = 2 * len2;
- int i;
-
- /* Tested and verified to work on everything in between */
- if ((N < 2) || (N > 13))
- return AVERROR(EINVAL);
-
- s = av_mallocz(sizeof(*s));
- if (!s)
- return AVERROR(ENOMEM);
-
- s->fft_n = N - 1;
- s->len4 = len2 / 2;
- s->len2 = len2;
- s->inverse = inverse;
- s->mdct = mdct15;
- s->imdct_half = imdct15_half;
-
- if (ff_fft_init(&s->ptwo_fft, N - 1, s->inverse) < 0)
- goto fail;
-
- if (init_pfa_reindex_tabs(s))
- goto fail;
-
- s->tmp = av_malloc_array(len, 2 * sizeof(*s->tmp));
- if (!s->tmp)
- goto fail;
-
- s->twiddle_exptab = av_malloc_array(s->len4, sizeof(*s->twiddle_exptab));
- if (!s->twiddle_exptab)
- goto fail;
-
- theta = 0.125f + (scale < 0 ? s->len4 : 0);
- scale = sqrt(fabs(scale));
- for (i = 0; i < s->len4; i++) {
- alpha = 2 * M_PI * (i + theta) / len;
- s->twiddle_exptab[i].re = cos(alpha) * scale;
- s->twiddle_exptab[i].im = sin(alpha) * scale;
- }
-
- /* 15-point FFT exptab */
- for (i = 0; i < 19; i++) {
- if (i < 15) {
- double theta = (2.0f * M_PI * i) / 15.0f;
- if (!s->inverse)
- theta *= -1;
- s->exptab[i].re = cos(theta);
- s->exptab[i].im = sin(theta);
- } else { /* Wrap around to simplify fft15 */
- s->exptab[i] = s->exptab[i - 15];
- }
- }
-
- /* 5-point FFT exptab */
- s->exptab[19].re = cos(2.0f * M_PI / 5.0f);
- s->exptab[19].im = sin(2.0f * M_PI / 5.0f);
- s->exptab[20].re = cos(1.0f * M_PI / 5.0f);
- s->exptab[20].im = sin(1.0f * M_PI / 5.0f);
-
- /* Invert the phase for an inverse transform, do nothing for a forward transform */
- if (s->inverse) {
- s->exptab[19].im *= -1;
- s->exptab[20].im *= -1;
- }
-
- *ps = s;
-
- return 0;
-
-fail:
- ff_mdct15_uninit(&s);
- return AVERROR(ENOMEM);
-}
-
/* Stride is hardcoded to 3 */
-static inline void fft5(const FFTComplex exptab[2], FFTComplex *out,
- const FFTComplex *in)
+static inline void fft5(FFTComplex *out, FFTComplex *in, FFTComplex exptab[2])
{
FFTComplex z0[4], t[6];
@@ -219,14 +134,14 @@ static inline void fft5(const FFTComplex exptab[2], FFTComplex *out,
out[4].im = in[0].im + z0[3].im;
}
-static void fft15(const FFTComplex exptab[22], FFTComplex *out, const FFTComplex *in, size_t stride)
+static void fft15_c(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride)
{
int k;
FFTComplex tmp1[5], tmp2[5], tmp3[5];
- fft5(exptab + 19, tmp1, in + 0);
- fft5(exptab + 19, tmp2, in + 1);
- fft5(exptab + 19, tmp3, in + 2);
+ fft5(tmp1, in + 0, exptab + 19);
+ fft5(tmp2, in + 1, exptab + 19);
+ fft5(tmp3, in + 2, exptab + 19);
for (k = 0; k < 5; k++) {
FFTComplex t[2];
@@ -269,7 +184,7 @@ static void mdct15(MDCT15Context *s, float *dst, const float *src, ptrdiff_t str
}
CMUL(fft15in[j].re, fft15in[j].im, re, im, s->twiddle_exptab[k].re, -s->twiddle_exptab[k].im);
}
- fft15(s->exptab, s->tmp + s->ptwo_fft.revtab[i], fft15in, l_ptwo);
+ s->fft15(s->tmp + s->ptwo_fft.revtab[i], fft15in, s->exptab, l_ptwo);
}
/* Then a 15xN FFT (where N is a power of two) */
@@ -306,7 +221,7 @@ static void imdct15_half(MDCT15Context *s, float *dst, const float *src,
FFTComplex tmp = { *(in2 - 2*k*stride), *(in1 + 2*k*stride) };
CMUL3(fft15in[j], tmp, s->twiddle_exptab[k]);
}
- fft15(s->exptab, s->tmp + s->ptwo_fft.revtab[i], fft15in, l_ptwo);
+ s->fft15(s->tmp + s->ptwo_fft.revtab[i], fft15in, s->exptab, l_ptwo);
}
/* Then a 15xN FFT (where N is a power of two) */
@@ -327,3 +242,86 @@ static void imdct15_half(MDCT15Context *s, float *dst, const float *src,
z[i0].im = scale * im1;
}
}
+
+av_cold int ff_mdct15_init(MDCT15Context **ps, int inverse, int N, double scale)
+{
+ MDCT15Context *s;
+ double alpha, theta;
+ int len2 = 15 * (1 << N);
+ int len = 2 * len2;
+ int i;
+
+ /* Tested and verified to work on everything in between */
+ if ((N < 2) || (N > 13))
+ return AVERROR(EINVAL);
+
+ s = av_mallocz(sizeof(*s));
+ if (!s)
+ return AVERROR(ENOMEM);
+
+ s->fft_n = N - 1;
+ s->len4 = len2 / 2;
+ s->len2 = len2;
+ s->inverse = inverse;
+ s->fft15 = fft15_c;
+ s->mdct = mdct15;
+ s->imdct_half = imdct15_half;
+
+ if (ff_fft_init(&s->ptwo_fft, N - 1, s->inverse) < 0)
+ goto fail;
+
+ if (init_pfa_reindex_tabs(s))
+ goto fail;
+
+ s->tmp = av_malloc_array(len, 2 * sizeof(*s->tmp));
+ if (!s->tmp)
+ goto fail;
+
+ s->twiddle_exptab = av_malloc_array(s->len4, sizeof(*s->twiddle_exptab));
+ if (!s->twiddle_exptab)
+ goto fail;
+
+ theta = 0.125f + (scale < 0 ? s->len4 : 0);
+ scale = sqrt(fabs(scale));
+ for (i = 0; i < s->len4; i++) {
+ alpha = 2 * M_PI * (i + theta) / len;
+ s->twiddle_exptab[i].re = cosf(alpha) * scale;
+ s->twiddle_exptab[i].im = sinf(alpha) * scale;
+ }
+
+ /* 15-point FFT exptab */
+ for (i = 0; i < 19; i++) {
+ if (i < 15) {
+ double theta = (2.0f * M_PI * i) / 15.0f;
+ if (!s->inverse)
+ theta *= -1;
+ s->exptab[i].re = cosf(theta);
+ s->exptab[i].im = sinf(theta);
+ } else { /* Wrap around to simplify fft15 */
+ s->exptab[i] = s->exptab[i - 15];
+ }
+ }
+
+ /* 5-point FFT exptab */
+ s->exptab[19].re = cosf(2.0f * M_PI / 5.0f);
+ s->exptab[19].im = sinf(2.0f * M_PI / 5.0f);
+ s->exptab[20].re = cosf(1.0f * M_PI / 5.0f);
+ s->exptab[20].im = sinf(1.0f * M_PI / 5.0f);
+
+ /* Invert the phase for an inverse transform, do nothing for a forward transform */
+ if (s->inverse) {
+ s->exptab[19].im *= -1;
+ s->exptab[20].im *= -1;
+ }
+
+ if (ARCH_X86)
+ ff_mdct15_init_x86(s);
+
+ *ps = s;
+
+ return 0;
+
+fail:
+ ff_mdct15_uninit(&s);
+ return AVERROR(ENOMEM);
+}
diff --git a/libavcodec/mdct15.h b/libavcodec/mdct15.h
index ef94edff6c..7d83f3ebdf 100644
--- a/libavcodec/mdct15.h
+++ b/libavcodec/mdct15.h
@@ -34,34 +34,26 @@ typedef struct MDCT15Context {
int *pfa_postreindex;
FFTContext ptwo_fft;
-
FFTComplex *tmp;
-
FFTComplex *twiddle_exptab;
- /* 0 - 18: fft15 twiddles, 19 - 20: fft5 twiddles */
- FFTComplex exptab[21];
+ DECLARE_ALIGNED(32, FFTComplex, exptab)[64];
- /**
- * Calculate a full 2N -> N MDCT
- */
+ /* 15-point FFT */
+ void (*fft15)(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride);
+
+ /* Calculate a full 2N -> N MDCT */
void (*mdct)(struct MDCT15Context *s, float *dst, const float *src, ptrdiff_t stride);
- /**
- * Calculate the middle half of the iMDCT
- */
+ /* Calculate the middle half of the iMDCT */
void (*imdct_half)(struct MDCT15Context *s, float *dst, const float *src,
ptrdiff_t src_stride, float scale);
} MDCT15Context;
-/**
- * Init an (i)MDCT of the length 2 * 15 * (2^N)
- */
+/* Init an (i)MDCT of the length 2 * 15 * (2^N) */
int ff_mdct15_init(MDCT15Context **ps, int inverse, int N, double scale);
-
-/**
- * Frees a context
- */
void ff_mdct15_uninit(MDCT15Context **ps);
+void ff_mdct15_init_x86(MDCT15Context *s);
+
#endif /* AVCODEC_MDCT15_H */
diff --git a/libavcodec/x86/Makefile b/libavcodec/x86/Makefile
index e65118d134..b86700b675 100644
--- a/libavcodec/x86/Makefile
+++ b/libavcodec/x86/Makefile
@@ -25,6 +25,7 @@ OBJS-$(CONFIG_HUFFYUVDSP) += x86/huffyuvdsp_init.o
OBJS-$(CONFIG_HUFFYUVENCDSP) += x86/huffyuvencdsp_init.o
OBJS-$(CONFIG_IDCTDSP) += x86/idctdsp_init.o
OBJS-$(CONFIG_LPC) += x86/lpc.o
+OBJS-$(CONFIG_MDCT15) += x86/mdct15_init.o
OBJS-$(CONFIG_ME_CMP) += x86/me_cmp_init.o
OBJS-$(CONFIG_MPEGAUDIODSP) += x86/mpegaudiodsp.o
OBJS-$(CONFIG_MPEGVIDEO) += x86/mpegvideo.o \
@@ -117,6 +118,7 @@ X86ASM-OBJS-$(CONFIG_IDCTDSP) += x86/idctdsp.o
X86ASM-OBJS-$(CONFIG_LLAUDDSP) += x86/lossless_audiodsp.o
X86ASM-OBJS-$(CONFIG_LLVIDDSP) += x86/lossless_videodsp.o
X86ASM-OBJS-$(CONFIG_LLVIDENCDSP) += x86/lossless_videoencdsp.o
+X86ASM-OBJS-$(CONFIG_MDCT15) += x86/mdct15.o
X86ASM-OBJS-$(CONFIG_ME_CMP) += x86/me_cmp.o
X86ASM-OBJS-$(CONFIG_MPEGAUDIODSP) += x86/imdct36.o
X86ASM-OBJS-$(CONFIG_MPEGVIDEOENC) += x86/mpegvideoencdsp.o
diff --git a/libavcodec/x86/mdct15.asm b/libavcodec/x86/mdct15.asm
new file mode 100644
index 0000000000..55c7f0268a
--- /dev/null
+++ b/libavcodec/x86/mdct15.asm
@@ -0,0 +1,137 @@
+;******************************************************************************
+;* SIMD optimized non-power-of-two MDCT functions
+;*
+;* Copyright (C) 2017 Rostislav Pehlivanov <atomnuker at gmail.com>
+;*
+;* 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"
+
+SECTION_RODATA
+
+sign_adjust_5: dd 0x00000000, 0x80000000, 0x80000000, 0x00000000
+
+SECTION .text
+
+%macro FFT5 3 ; %1 - in_offset, %2 - dst1 (64bit used), %3 - dst2
+ VBROADCASTSD m0, [inq + %1] ; in[ 0].re, in[ 0].im, in[ 0].re, in[ 0].im
+ movsd xm1, [inq + 1*16 + 8 + %1] ; in[ 3].re, in[ 3].im, 0, 0
+ movsd xm4, [inq + 6*16 + 0 + %1] ; in[12].re, in[12].im, 0, 0
+ movhps xm1, [inq + 3*16 + 0 + %1] ; in[ 3].re, in[ 3].im, in[ 6].re, in[ 6].im
+ movhps xm4, [inq + 4*16 + 8 + %1] ; in[12].re, in[12].im, in[ 9].re, in[ 9].im
+
+ subps xm2, xm1, xm4 ; t[2].im, t[2].re, t[3].im, t[3].re
+ addps xm1, xm4 ; t[0].re, t[0].im, t[1].re, t[1].im
+
+ movhlps %2, xm1 ; t[0].re, t[1].re, t[0].im, t[1].im
+ addps %2, xm1
+ addps %2, xm0 ; DC[0].re, DC[0].im, junk...
+ movlhps %2, %2 ; DC[0].re, DC[0].im, DC[0].re, DC[0].im
+
+ shufps xm3, xm1, xm2, q0110 ; t[0].re, t[0].im, t[2].re, t[2].im
+ shufps xm1, xm2, q2332 ; t[1].re, t[1].im, t[3].re, t[3].im
+
+ mulps xm%3, xm1, xm5
+ mulps xm4, xm3, xm6
+ mulps xm1, xm6
+
+ xorps xm1, xm7
+ mulps xm3, xm5
+ addsubps xm3, xm1 ; t[0].re, t[0].im, t[2].re, t[2].im
+ subps xm%3, xm4 ; t[4].re, t[4].im, t[5].re, t[5].im
+
+ movhlps xm2, xm%3, xm3 ; t[2].re, t[2].im, t[5].re, t[5].im
+ movlhps xm3, xm%3 ; t[0].re, t[0].im, t[4].re, t[4].im
+
+ xorps xm2, xm7
+ addps xm%3, xm2, xm3
+ subps xm3, xm2
+
+ shufps xm3, xm3, q1032
+ vinsertf128 m%3, xm3, 1 ; All ACs (tmp[1] through to tmp[4])
+ addps m%3, m0 ; Finally offset with DCs
+%endmacro
+
+%macro BUTTERFLIES_DC 2 ; %1 - exptab_offset, %2 - out
+ mulps xm0, xm9, [exptabq + %1 + 16*0]
+ mulps xm1, xm10, [exptabq + %1 + 16*1]
+
+ haddps xm0, xm1
+ movhlps xm1, xm0 ; t[0].re, t[1].re, t[0].im, t[1].im
+
+ addps xm0, xm1
+ addps xm0, xm8
+
+ movsd [%2q], xm0
+%endmacro
+
+%macro BUTTERFLIES_AC 2 ; exptab, exptab_offset, src1, src2, src3, out (uses m0-m3)
+ mulps m1, m12, [exptabq + 64*0 + 1*mmsize + %1]
+ mulps m0, m12, [exptabq + 64*0 + 0*mmsize + %1]
+ mulps m2, m13, [exptabq + 64*1 + 0*mmsize + %1]
+ mulps m3, m13, [exptabq + 64*1 + 1*mmsize + %1]
+
+ addps m0, m2
+ addps m1, m3
+ addps m0, m11
+
+ shufps m1, m1, q2301
+ addps m0, m1
+
+ vextractf128 xm1, m0, 1
+
+ movlps [%2q + strideq*1], xm0
+ movhps [%2q + strideq*2], xm0
+ movlps [%2q + stride3q], xm1
+ movhps [%2q + strideq*4], xm1
+%endmacro
+
+;*****************************************************************************************
+;void ff_fft15_avx(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride);
+;*****************************************************************************************
+INIT_YMM avx
+cglobal fft15, 4, 6, 14, out, in, exptab, stride, stride3, stride5
+%define out0q inq
+ shl strideq, 3
+
+ movaps xm5, [exptabq + 480 + 16*0]
+ movaps xm6, [exptabq + 480 + 16*1]
+ movaps xm7, [sign_adjust_5]
+
+ FFT5 0, xm8, 11
+ FFT5 8, xm9, 12
+ FFT5 16, xm10, 13
+
+ lea stride3q, [strideq + strideq*2]
+ lea stride5q, [strideq + strideq*4]
+
+ mov out0q, outq
+
+ BUTTERFLIES_DC (8*6 + 4*0)*2*4, out0
+ lea outq, [out0q + stride5q*1]
+ BUTTERFLIES_DC (8*6 + 4*1)*2*4, out
+ lea outq, [out0q + stride5q*2]
+ BUTTERFLIES_DC (8*6 + 4*2)*2*4, out
+
+ BUTTERFLIES_AC (8*0)*2*4, out0
+ lea outq, [out0q + stride5q*1]
+ BUTTERFLIES_AC (8*2)*2*4, out
+ lea outq, [out0q + stride5q*2]
+ BUTTERFLIES_AC (8*4)*2*4, out
+
+ RET
diff --git a/libavcodec/x86/mdct15_init.c b/libavcodec/x86/mdct15_init.c
new file mode 100644
index 0000000000..ba3d94c2ec
--- /dev/null
+++ b/libavcodec/x86/mdct15_init.c
@@ -0,0 +1,95 @@
+/*
+ * SIMD optimized non-power-of-two MDCT functions
+ *
+ * Copyright (C) 2017 Rostislav Pehlivanov <atomnuker at gmail.com>
+ *
+ * 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/x86/cpu.h"
+#include "libavcodec/mdct15.h"
+
+void ff_fft15_avx(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride);
+
+static void perm_twiddles(MDCT15Context *s)
+{
+ int k;
+ FFTComplex exp_5point[4];
+
+ FFTComplex tmp[21], tmp2[30];
+ memcpy(tmp, s->exptab, sizeof(FFTComplex)*21);
+
+ /* 15-point FFT twiddles */
+ for (k = 0; k < 5; k++) {
+ tmp2[6*k + 0] = tmp[k + 0];
+ tmp2[6*k + 2] = tmp[k + 5];
+ tmp2[6*k + 4] = tmp[k + 10];
+
+ tmp2[6*k + 1] = tmp[2 * (k + 0)];
+ tmp2[6*k + 3] = tmp[2 * (k + 5)];
+ tmp2[6*k + 5] = tmp[2 * k + 5 ];
+ }
+
+ for (k = 0; k < 6; k++) {
+ FFTComplex ac_exp[] = {
+ { tmp2[6*1 + k].re, tmp2[6*1 + k].re },
+ { tmp2[6*2 + k].re, tmp2[6*2 + k].re },
+ { tmp2[6*3 + k].re, tmp2[6*3 + k].re },
+ { tmp2[6*4 + k].re, tmp2[6*4 + k].re },
+ { tmp2[6*1 + k].im, -tmp2[6*1 + k].im },
+ { tmp2[6*2 + k].im, -tmp2[6*2 + k].im },
+ { tmp2[6*3 + k].im, -tmp2[6*3 + k].im },
+ { tmp2[6*4 + k].im, -tmp2[6*4 + k].im },
+ };
+ memcpy(s->exptab + 8*k, ac_exp, 8*sizeof(FFTComplex));
+ }
+
+ /* Specialcase when k = 0 */
+ for (k = 0; k < 3; k++) {
+ FFTComplex dc_exp[] = {
+ { tmp2[2*k + 0].re, -tmp2[2*k + 0].im },
+ { tmp2[2*k + 0].im, tmp2[2*k + 0].re },
+ { tmp2[2*k + 1].re, -tmp2[2*k + 1].im },
+ { tmp2[2*k + 1].im, tmp2[2*k + 1].re },
+ };
+ memcpy(s->exptab + 8*6 + 4*k, dc_exp, 4*sizeof(FFTComplex));
+ }
+
+ /* 5-point FFT twiddles */
+ exp_5point[0].re = exp_5point[0].im = tmp[19].re;
+ exp_5point[1].re = exp_5point[1].im = tmp[19].im;
+ exp_5point[2].re = exp_5point[2].im = tmp[20].re;
+ exp_5point[3].re = exp_5point[3].im = tmp[20].im;
+
+ memcpy(s->exptab + 8*6 + 4*3, exp_5point, 4*sizeof(FFTComplex));
+}
+
+av_cold void ff_mdct15_init_x86(MDCT15Context *s)
+{
+ int adjust_twiddles = 0;
+ int cpu_flags = av_get_cpu_flags();
+
+ if (ARCH_X86_64 && EXTERNAL_AVX(cpu_flags)) {
+ s->fft15 = ff_fft15_avx;
+ adjust_twiddles = 1;
+ }
+
+ if (adjust_twiddles)
+ perm_twiddles(s);
+}
--
2.13.1.704.gde00cce3c
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