arm: vp9: Add NEON optimizations of VP9 MC functions

This work is sponsored by, and copyright, Google.

The filter coefficients are signed values, where the product of the
multiplication with one individual filter coefficient doesn't
overflow a 16 bit signed value (the largest filter coefficient is
127). But when the products are accumulated, the resulting sum can
overflow the 16 bit signed range. Instead of accumulating in 32 bit,
we accumulate the largest product (either index 3 or 4) last with a
saturated addition.

(The VP8 MC asm does something similar, but slightly simpler, by
accumulating each half of the filter separately. In the VP9 MC
filters, each half of the filter can also overflow though, so the
largest component has to be handled individually.)

Examples of relative speedup compared to the C version, from checkasm:
                       Cortex      A7     A8     A9    A53
vp9_avg4_neon:                   1.71   1.15   1.42   1.49
vp9_avg8_neon:                   2.51   3.63   3.14   2.58
vp9_avg16_neon:                  2.95   6.76   3.01   2.84
vp9_avg32_neon:                  3.29   6.64   2.85   3.00
vp9_avg64_neon:                  3.47   6.67   3.14   2.80
vp9_avg_8tap_smooth_4h_neon:     3.22   4.73   2.76   4.67
vp9_avg_8tap_smooth_4hv_neon:    3.67   4.76   3.28   4.71
vp9_avg_8tap_smooth_4v_neon:     5.52   7.60   4.60   6.31
vp9_avg_8tap_smooth_8h_neon:     6.22   9.04   5.12   9.32
vp9_avg_8tap_smooth_8hv_neon:    6.38   8.21   5.72   8.17
vp9_avg_8tap_smooth_8v_neon:     9.22  12.66   8.15  11.10
vp9_avg_8tap_smooth_64h_neon:    7.02  10.23   5.54  11.58
vp9_avg_8tap_smooth_64hv_neon:   6.76   9.46   5.93   9.40
vp9_avg_8tap_smooth_64v_neon:   10.76  14.13   9.46  13.37
vp9_put4_neon:                   1.11   1.47   1.00   1.21
vp9_put8_neon:                   1.23   2.17   1.94   1.48
vp9_put16_neon:                  1.63   4.02   1.73   1.97
vp9_put32_neon:                  1.56   4.92   2.00   1.96
vp9_put64_neon:                  2.10   5.28   2.03   2.35
vp9_put_8tap_smooth_4h_neon:     3.11   4.35   2.63   4.35
vp9_put_8tap_smooth_4hv_neon:    3.67   4.69   3.25   4.71
vp9_put_8tap_smooth_4v_neon:     5.45   7.27   4.49   6.52
vp9_put_8tap_smooth_8h_neon:     5.97   8.18   4.81   8.56
vp9_put_8tap_smooth_8hv_neon:    6.39   7.90   5.64   8.15
vp9_put_8tap_smooth_8v_neon:     9.03  11.84   8.07  11.51
vp9_put_8tap_smooth_64h_neon:    6.78   9.48   4.88  10.89
vp9_put_8tap_smooth_64hv_neon:   6.99   8.87   5.94   9.56
vp9_put_8tap_smooth_64v_neon:   10.69  13.30   9.43  14.34

For the larger 8tap filters, the speedup vs C code is around 5-14x.

This is significantly faster than libvpx's implementation of the same
functions, at least when comparing the put_8tap_smooth_64 functions
(compared to vpx_convolve8_horiz_neon and vpx_convolve8_vert_neon from
libvpx).

Absolute runtimes from checkasm:
                          Cortex      A7        A8        A9       A53
vp9_put_8tap_smooth_64h_neon:    20150.3   14489.4   19733.6   10863.7
libvpx vpx_convolve8_horiz_neon: 52623.3   19736.4   21907.7   25027.7

vp9_put_8tap_smooth_64v_neon:    14455.0   12303.9   13746.4    9628.9
libvpx vpx_convolve8_vert_neon:  42090.0   17706.2   17659.9   16941.2

Thus, on the A9, the horizontal filter is only marginally faster than
libvpx, while our version is significantly faster on the other cores,
and the vertical filter is significantly faster on all cores. The
difference is especially large on the A7.

The libvpx implementation does the accumulation in 32 bit, which
probably explains most of the differences.

This is an adapted cherry-pick from libav commits
ffbd1d2b,
392caa65,
557c1675 and
11623217.
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>

libavcodec/arm/Makefile

@@ -44,6 +44,7 @@ OBJS-$(CONFIG_MLP_DECODER)             += arm/mlpdsp_init_arm.o
 OBJS-$(CONFIG_RV40_DECODER)            += arm/rv40dsp_init_arm.o
 OBJS-$(CONFIG_VORBIS_DECODER)          += arm/vorbisdsp_init_arm.o
 OBJS-$(CONFIG_VP6_DECODER)             += arm/vp6dsp_init_arm.o
+OBJS-$(CONFIG_VP9_DECODER)             += arm/vp9dsp_init_arm.o
 
 
 # ARMv5 optimizations
@@ -139,3 +140,4 @@ NEON-OBJS-$(CONFIG_RV40_DECODER)       += arm/rv34dsp_neon.o            \
                                           arm/rv40dsp_neon.o
 NEON-OBJS-$(CONFIG_VORBIS_DECODER)     += arm/vorbisdsp_neon.o
 NEON-OBJS-$(CONFIG_VP6_DECODER)        += arm/vp6dsp_neon.o
+NEON-OBJS-$(CONFIG_VP9_DECODER)        += arm/vp9mc_neon.o

libavcodec/arm/vp9dsp_init_arm.c

+/*
+ * Copyright (c) 2016 Google Inc.
+ *
+ * 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 <stdint.h>
+
+#include "libavutil/attributes.h"
+#include "libavutil/arm/cpu.h"
+#include "libavcodec/vp9dsp.h"
+
+#define declare_fpel(type, sz)                                          \
+void ff_vp9_##type##sz##_neon(uint8_t *dst, ptrdiff_t dst_stride,       \
+                              const uint8_t *src, ptrdiff_t src_stride, \
+                              int h, int mx, int my)
+
+#define declare_copy_avg(sz) \
+    declare_fpel(copy, sz);  \
+    declare_fpel(avg , sz)
+
+#define decl_mc_func(op, filter, dir, sz)                                                \
+void ff_vp9_##op##_##filter##sz##_##dir##_neon(uint8_t *dst, ptrdiff_t dst_stride,       \
+                                               const uint8_t *src, ptrdiff_t src_stride, \
+                                               int h, int mx, int my)
+
+#define define_8tap_2d_fn(op, filter, sz)                                         \
+static void op##_##filter##sz##_hv_neon(uint8_t *dst, ptrdiff_t dst_stride,       \
+                                        const uint8_t *src, ptrdiff_t src_stride, \
+                                        int h, int mx, int my)                    \
+{                                                                                 \
+    LOCAL_ALIGNED_16(uint8_t, temp, [((1 + (sz < 64)) * sz + 8) * sz]);           \
+    /* We only need h + 7 lines, but the horizontal filter assumes an             \
+     * even number of rows, so filter h + 8 lines here. */                        \
+    ff_vp9_put_##filter##sz##_h_neon(temp, sz,                                    \
+                                     src - 3 * src_stride, src_stride,            \
+                                     h + 8, mx, 0);                               \
+    ff_vp9_##op##_##filter##sz##_v_neon(dst, dst_stride,                          \
+                                        temp + 3 * sz, sz,                        \
+                                        h, 0, my);                                \
+}
+
+#define decl_filter_funcs(op, dir, sz)  \
+    decl_mc_func(op, regular, dir, sz); \
+    decl_mc_func(op, sharp,   dir, sz); \
+    decl_mc_func(op, smooth,  dir, sz)
+
+#define decl_mc_funcs(sz)           \
+    decl_filter_funcs(put, h,  sz); \
+    decl_filter_funcs(avg, h,  sz); \
+    decl_filter_funcs(put, v,  sz); \
+    decl_filter_funcs(avg, v,  sz); \
+    decl_filter_funcs(put, hv, sz); \
+    decl_filter_funcs(avg, hv, sz)
+
+declare_copy_avg(64);
+declare_copy_avg(32);
+declare_copy_avg(16);
+declare_copy_avg(8);
+declare_copy_avg(4);
+
+decl_mc_funcs(64);
+decl_mc_funcs(32);
+decl_mc_funcs(16);
+decl_mc_funcs(8);
+decl_mc_funcs(4);
+
+#define define_8tap_2d_funcs(sz)        \
+    define_8tap_2d_fn(put, regular, sz) \
+    define_8tap_2d_fn(put, sharp,   sz) \
+    define_8tap_2d_fn(put, smooth,  sz) \
+    define_8tap_2d_fn(avg, regular, sz) \
+    define_8tap_2d_fn(avg, sharp,   sz) \
+    define_8tap_2d_fn(avg, smooth,  sz)
+
+define_8tap_2d_funcs(64)
+define_8tap_2d_funcs(32)
+define_8tap_2d_funcs(16)
+define_8tap_2d_funcs(8)
+define_8tap_2d_funcs(4)
+
+
+av_cold void ff_vp9dsp_init_arm(VP9DSPContext *dsp, int bpp)
+{
+    int cpu_flags = av_get_cpu_flags();
+
+    if (bpp != 8)
+        return;
+
+    if (have_neon(cpu_flags)) {
+#define init_fpel(idx1, idx2, sz, type)              \
+    dsp->mc[idx1][FILTER_8TAP_SMOOTH ][idx2][0][0] = \
+    dsp->mc[idx1][FILTER_8TAP_REGULAR][idx2][0][0] = \
+    dsp->mc[idx1][FILTER_8TAP_SHARP  ][idx2][0][0] = \
+    dsp->mc[idx1][FILTER_BILINEAR    ][idx2][0][0] = ff_vp9_##type##sz##_neon
+
+#define init_copy_avg(idx, sz)   \
+    init_fpel(idx, 0, sz, copy); \
+    init_fpel(idx, 1, sz, avg)
+
+#define init_mc_func(idx1, idx2, op, filter, fname, dir, mx, my, sz, pfx) \
+    dsp->mc[idx1][filter][idx2][mx][my] = pfx##op##_##fname##sz##_##dir##_neon
+
+#define init_mc_funcs(idx, dir, mx, my, sz, pfx)                                   \
+    init_mc_func(idx, 0, put, FILTER_8TAP_REGULAR, regular, dir, mx, my, sz, pfx); \
+    init_mc_func(idx, 0, put, FILTER_8TAP_SHARP,   sharp,   dir, mx, my, sz, pfx); \
+    init_mc_func(idx, 0, put, FILTER_8TAP_SMOOTH,  smooth,  dir, mx, my, sz, pfx); \
+    init_mc_func(idx, 1, avg, FILTER_8TAP_REGULAR, regular, dir, mx, my, sz, pfx); \
+    init_mc_func(idx, 1, avg, FILTER_8TAP_SHARP,   sharp,   dir, mx, my, sz, pfx); \
+    init_mc_func(idx, 1, avg, FILTER_8TAP_SMOOTH,  smooth,  dir, mx, my, sz, pfx)
+
+#define init_mc_funcs_dirs(idx, sz)            \
+    init_mc_funcs(idx, h,  1, 0, sz, ff_vp9_); \
+    init_mc_funcs(idx, v,  0, 1, sz, ff_vp9_); \
+    init_mc_funcs(idx, hv, 1, 1, sz,)
+
+        init_copy_avg(0, 64);
+        init_copy_avg(1, 32);
+        init_copy_avg(2, 16);
+        init_copy_avg(3, 8);
+        init_copy_avg(4, 4);
+
+        init_mc_funcs_dirs(0, 64);
+        init_mc_funcs_dirs(1, 32);
+        init_mc_funcs_dirs(2, 16);
+        init_mc_funcs_dirs(3, 8);
+        init_mc_funcs_dirs(4, 4);
+    }
+}

libavcodec/arm/vp9mc_neon.S

+/*
+ * Copyright (c) 2016 Google Inc.
+ *
+ * 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/arm/asm.S"
+
+@ All public functions in this file have the following signature:
+@ typedef void (*vp9_mc_func)(uint8_t *dst, ptrdiff_t dst_stride,
+@                            const uint8_t *ref, ptrdiff_t ref_stride,
+@                            int h, int mx, int my);
+
+function ff_vp9_copy64_neon, export=1
+        ldr             r12, [sp]
+        sub             r1,  r1,  #32
+        sub             r3,  r3,  #32
+1:
+        vld1.8          {q0,  q1},  [r2]!
+        vst1.8          {q0,  q1},  [r0, :128]!
+        vld1.8          {q2,  q3},  [r2], r3
+        subs            r12, r12, #1
+        vst1.8          {q2,  q3},  [r0, :128], r1
+        bne             1b
+        bx              lr
+endfunc
+
+function ff_vp9_avg64_neon, export=1
+        push            {lr}
+        ldr             r12, [sp, #4]
+        sub             r1,  r1,  #32
+        sub             r3,  r3,  #32
+        mov             lr,  r0
+1:
+        vld1.8          {q8,  q9},  [r2]!
+        vld1.8          {q0,  q1},  [r0, :128]!
+        vld1.8          {q10, q11}, [r2], r3
+        vrhadd.u8       q0,  q0,  q8
+        vld1.8          {q2,  q3},  [r0, :128], r1
+        vrhadd.u8       q1,  q1,  q9
+        vrhadd.u8       q2,  q2,  q10
+        vst1.8          {q0,  q1},  [lr, :128]!
+        vrhadd.u8       q3,  q3,  q11
+        vst1.8          {q2,  q3},  [lr, :128], r1
+        subs            r12, r12, #1
+        bne             1b
+        pop             {pc}
+endfunc
+
+function ff_vp9_copy32_neon, export=1
+        ldr             r12, [sp]
+1:
+        vld1.8          {q0,  q1},  [r2], r3
+        subs            r12, r12, #1
+        vst1.8          {q0,  q1},  [r0, :128], r1
+        bne             1b
+        bx              lr
+endfunc
+
+function ff_vp9_avg32_neon, export=1
+        ldr             r12, [sp]
+1:
+        vld1.8          {q2,  q3},  [r2], r3
+        vld1.8          {q0,  q1},  [r0, :128]
+        vrhadd.u8       q0,  q0,  q2
+        vrhadd.u8       q1,  q1,  q3
+        subs            r12, r12, #1
+        vst1.8          {q0, q1},  [r0, :128], r1
+        bne             1b
+        bx              lr
+endfunc
+
+function ff_vp9_copy16_neon, export=1
+        push            {r4,lr}
+        ldr             r12, [sp, #8]
+        add             r4,  r0,  r1
+        add             lr,  r2,  r3
+        add             r1,  r1,  r1
+        add             r3,  r3,  r3
+1:
+        vld1.8          {q0},  [r2], r3
+        vld1.8          {q1},  [lr], r3
+        subs            r12, r12, #2
+        vst1.8          {q0},  [r0, :128], r1
+        vst1.8          {q1},  [r4, :128], r1
+        bne             1b
+        pop             {r4,pc}
+endfunc
+
+function ff_vp9_avg16_neon, export=1
+        push            {lr}
+        ldr             r12, [sp, #4]
+        mov             lr,  r0
+1:
+        vld1.8          {q2},  [r2], r3
+        vld1.8          {q0},  [r0, :128], r1
+        vld1.8          {q3},  [r2], r3
+        vrhadd.u8       q0,  q0,  q2
+        vld1.8          {q1},  [r0, :128], r1
+        vrhadd.u8       q1,  q1,  q3
+        subs            r12, r12, #2
+        vst1.8          {q0},  [lr, :128], r1
+        vst1.8          {q1},  [lr, :128], r1
+        bne             1b
+        pop             {pc}
+endfunc
+
+function ff_vp9_copy8_neon, export=1
+        ldr             r12, [sp]
+1:
+        vld1.8          {d0},  [r2], r3
+        vld1.8          {d1},  [r2], r3
+        subs            r12, r12, #2
+        vst1.8          {d0},  [r0, :64], r1
+        vst1.8          {d1},  [r0, :64], r1
+        bne             1b
+        bx              lr
+endfunc
+
+function ff_vp9_avg8_neon, export=1
+        ldr             r12, [sp]
+1:
+        vld1.8          {d2},  [r2], r3
+        vld1.8          {d0},  [r0, :64], r1
+        vld1.8          {d3},  [r2], r3
+        vrhadd.u8       d0,  d0,  d2
+        vld1.8          {d1},  [r0, :64]
+        sub             r0,  r0,  r1
+        vrhadd.u8       d1,  d1,  d3
+        subs            r12, r12, #2
+        vst1.8          {d0},  [r0, :64], r1
+        vst1.8          {d1},  [r0, :64], r1
+        bne             1b
+        bx              lr
+endfunc
+
+function ff_vp9_copy4_neon, export=1
+        ldr             r12, [sp]
+1:
+        vld1.32         {d0[]},   [r2], r3
+        vld1.32         {d1[]},   [r2], r3
+        vst1.32         {d0[0]},  [r0, :32], r1
+        vld1.32         {d2[]},   [r2], r3
+        vst1.32         {d1[0]},  [r0, :32], r1
+        vld1.32         {d3[]},   [r2], r3
+        subs            r12, r12, #4
+        vst1.32         {d2[0]},  [r0, :32], r1
+        vst1.32         {d3[0]},  [r0, :32], r1
+        bne             1b
+        bx              lr
+endfunc
+
+function ff_vp9_avg4_neon, export=1
+        push            {lr}
+        ldr             r12, [sp, #4]
+        mov             lr,  r0
+1:
+        vld1.32         {d4[]},   [r2], r3
+        vld1.32         {d0[]},   [r0, :32], r1
+        vld1.32         {d5[]},   [r2], r3
+        vrhadd.u8       d0,  d0,  d4
+        vld1.32         {d1[]},   [r0, :32], r1
+        vld1.32         {d6[]},   [r2], r3
+        vrhadd.u8       d1,  d1,  d5
+        vld1.32         {d2[]},   [r0, :32], r1
+        vld1.32         {d7[]},   [r2], r3
+        vrhadd.u8       d2,  d2,  d6
+        vld1.32         {d3[]},   [r0, :32], r1
+        subs            r12, r12, #4
+        vst1.32         {d0[0]},  [lr, :32], r1
+        vrhadd.u8       d3,  d3,  d7
+        vst1.32         {d1[0]},  [lr, :32], r1
+        vst1.32         {d2[0]},  [lr, :32], r1
+        vst1.32         {d3[0]},  [lr, :32], r1
+        bne             1b
+        pop             {pc}
+endfunc
+
+@ Helper macros for vmul/vmla with a constant from either d0 or d1 depending on index
+.macro vmul_lane dst, src, idx
+.if \idx < 4
+       vmul.s16         \dst, \src, d0[\idx]
+.else
+       vmul.s16         \dst, \src, d1[\idx - 4]
+.endif
+.endm
+.macro vmla_lane dst, src, idx
+.if \idx < 4
+       vmla.s16         \dst, \src, d0[\idx]
+.else
+       vmla.s16         \dst, \src, d1[\idx - 4]
+.endif
+.endm
+
+@ Extract a vector from src1-src2 and src4-src5 (src1-src3 and src4-src6
+@ for size >= 16), and multiply-accumulate into dst1 and dst3 (or
+@ dst1-dst2 and dst3-dst4 for size >= 16)
+.macro extmla dst1, dst2, dst3, dst4, src1, src2, src3, src4, src5, src6, offset, size
+        vext.8          q14, \src1, \src2, #(2*\offset)
+        vext.8          q15, \src4, \src5, #(2*\offset)
+.if \size >= 16
+        vmla_lane       \dst1,  q14, \offset
+        vext.8          q5,  \src2, \src3, #(2*\offset)
+        vmla_lane       \dst3,  q15, \offset
+        vext.8          q6,  \src5, \src6, #(2*\offset)
+        vmla_lane       \dst2,  q5,  \offset
+        vmla_lane       \dst4,  q6,  \offset
+.else
+        vmla_lane       \dst1,  q14, \offset
+        vmla_lane       \dst3,  q15, \offset
+.endif
+.endm
+@ The same as above, but don't accumulate straight into the
+@ destination, but use a temp register and accumulate with saturation.
+.macro extmulqadd dst1, dst2, dst3, dst4, src1, src2, src3, src4, src5, src6, offset, size
+        vext.8          q14, \src1, \src2, #(2*\offset)
+        vext.8          q15, \src4, \src5, #(2*\offset)
+.if \size >= 16
+        vmul_lane       q14, q14, \offset
+        vext.8          q5,  \src2, \src3, #(2*\offset)
+        vmul_lane       q15, q15, \offset
+        vext.8          q6,  \src5, \src6, #(2*\offset)
+        vmul_lane       q5,  q5,  \offset
+        vmul_lane       q6,  q6,  \offset
+.else
+        vmul_lane       q14, q14, \offset
+        vmul_lane       q15, q15, \offset
+.endif
+        vqadd.s16       \dst1,  \dst1,  q14
+        vqadd.s16       \dst3,  \dst3,  q15
+.if \size >= 16
+        vqadd.s16       \dst2,  \dst2,  q5
+        vqadd.s16       \dst4,  \dst4,  q6
+.endif
+.endm
+
+
+@ Instantiate a horizontal filter function for the given size.
+@ This can work on 4, 8 or 16 pixels in parallel; for larger
+@ widths it will do 16 pixels at a time and loop horizontally.
+@ The actual width is passed in r5, the height in r4 and
+@ the filter coefficients in r12. idx2 is the index of the largest
+@ filter coefficient (3 or 4) and idx1 is the other one of them.
+.macro do_8tap_h type, size, idx1, idx2
+function \type\()_8tap_\size\()h_\idx1\idx2
+        sub             r2,  r2,  #3
+        add             r6,  r0,  r1
+        add             r7,  r2,  r3
+        add             r1,  r1,  r1
+        add             r3,  r3,  r3
+        @ Only size >= 16 loops horizontally and needs
+        @ reduced dst stride
+.if \size >= 16
+        sub             r1,  r1,  r5
+.endif
+        @ size >= 16 loads two qwords and increments r2,
+        @ for size 4/8 it's enough with one qword and no
+        @ postincrement
+.if \size >= 16
+        sub             r3,  r3,  r5
+        sub             r3,  r3,  #8
+.endif
+        @ Load the filter vector
+        vld1.16         {q0},  [r12,:128]
+1:
+.if \size >= 16
+        mov             r12, r5
+.endif
+        @ Load src
+.if \size >= 16
+        vld1.8          {d18, d19, d20}, [r2]!
+        vld1.8          {d24, d25, d26}, [r7]!
+.else
+        vld1.8          {q9},  [r2]
+        vld1.8          {q12}, [r7]
+.endif
+        vmovl.u8        q8,  d18
+        vmovl.u8        q9,  d19
+        vmovl.u8        q11, d24
+        vmovl.u8        q12, d25
+.if \size >= 16
+        vmovl.u8        q10, d20
+        vmovl.u8        q13, d26
+.endif
+2:
+
+        @ Accumulate, adding idx2 last with a separate
+        @ saturating add. The positive filter coefficients
+        @ for all indices except idx2 must add up to less
+        @ than 127 for this not to overflow.
+        vmul.s16        q1,  q8,  d0[0]
+        vmul.s16        q3,  q11, d0[0]
+.if \size >= 16
+        vmul.s16        q2,  q9,  d0[0]
+        vmul.s16        q4,  q12, d0[0]
+.endif
+        extmla          q1,  q2,  q3,  q4,  q8,  q9,  q10,  q11, q12, q13, 1,     \size
+        extmla          q1,  q2,  q3,  q4,  q8,  q9,  q10,  q11, q12, q13, 2,     \size
+        extmla          q1,  q2,  q3,  q4,  q8,  q9,  q10,  q11, q12, q13, \idx1, \size
+        extmla          q1,  q2,  q3,  q4,  q8,  q9,  q10,  q11, q12, q13, 5,     \size
+        extmla          q1,  q2,  q3,  q4,  q8,  q9,  q10,  q11, q12, q13, 6,     \size
+        extmla          q1,  q2,  q3,  q4,  q8,  q9,  q10,  q11, q12, q13, 7,     \size
+        extmulqadd      q1,  q2,  q3,  q4,  q8,  q9,  q10,  q11, q12, q13, \idx2, \size
+
+        @ Round, shift and saturate
+        vqrshrun.s16    d2,  q1,  #7
+        vqrshrun.s16    d6,  q3,  #7
+.if \size >= 16
+        vqrshrun.s16    d3,  q2,  #7
+        vqrshrun.s16    d7,  q4,  #7
+.endif
+        @ Average
+.ifc \type,avg
+.if \size >= 16
+        vld1.8          {q14}, [r0,:128]
+        vld1.8          {q15}, [r6,:128]
+        vrhadd.u8       q1,  q1,  q14
+        vrhadd.u8       q3,  q3,  q15
+.elseif \size == 8
+        vld1.8          {d28}, [r0,:64]
+        vld1.8          {d30}, [r6,:64]
+        vrhadd.u8       d2,  d2,  d28
+        vrhadd.u8       d6,  d6,  d30
+.else
+        @ We only need d28[0], but [] is faster on some cores
+        vld1.32         {d28[]}, [r0,:32]
+        vld1.32         {d30[]}, [r6,:32]
+        vrhadd.u8       d2,  d2,  d28
+        vrhadd.u8       d6,  d6,  d30
+.endif
+.endif
+        @ Store and loop horizontally (for size >= 16)
+.if \size >= 16
+        subs            r12, r12, #16
+        vst1.8          {q1}, [r0,:128]!
+        vst1.8          {q3}, [r6,:128]!
+        beq             3f
+        vmov            q8,  q10
+        vmov            q11, q13
+        vld1.8          {q10}, [r2]!
+        vld1.8          {q13}, [r7]!
+        vmovl.u8        q9,  d20
+        vmovl.u8        q10, d21
+        vmovl.u8        q12, d26
+        vmovl.u8        q13, d27
+        b               2b
+.elseif \size == 8
+        vst1.8          {d2}, [r0,:64]
+        vst1.8          {d6}, [r6,:64]
+.else @ \size == 4
+        vst1.32         {d2[0]}, [r0,:32]
+        vst1.32         {d6[0]}, [r6,:32]
+.endif
+3:
+        @ Loop vertically
+        add             r0,  r0,  r1
+        add             r6,  r6,  r1
+        add             r2,  r2,  r3
+        add             r7,  r7,  r3
+        subs            r4,  r4,  #2
+        bne             1b
+.if \size >= 16
+        vpop            {q4-q6}
+.endif
+        pop             {r4-r7}
+        bx              lr
+endfunc
+.endm
+
+.macro do_8tap_h_size size
+do_8tap_h put, \size, 3, 4
+do_8tap_h avg, \size, 3, 4
+do_8tap_h put, \size, 4, 3
+do_8tap_h avg, \size, 4, 3
+.endm
+
+do_8tap_h_size 4
+do_8tap_h_size 8
+do_8tap_h_size 16
+
+.macro do_8tap_h_func type, filter, offset, size
+function ff_vp9_\type\()_\filter\()\size\()_h_neon, export=1
+        push            {r4-r7}
+.if \size >= 16
+        vpush           {q4-q6}
+        ldr             r4,  [sp, #64]
+        ldr             r5,  [sp, #68]
+.else
+        ldr             r4,  [sp, #16]
+        ldr             r5,  [sp, #20]
+.endif
+        movrelx         r12, X(ff_vp9_subpel_filters), r6
+        add             r12, r12, 256*\offset
+        cmp             r5,  #8
+        add             r12, r12, r5, lsl #4
+        mov             r5, #\size
+.if \size >= 16
+        bge             \type\()_8tap_16h_34
+        b               \type\()_8tap_16h_43
+.else
+        bge             \type\()_8tap_\size\()h_34
+        b               \type\()_8tap_\size\()h_43
+.endif
+endfunc
+.endm
+
+.macro do_8tap_h_filters size
+do_8tap_h_func put, regular, 1, \size
+do_8tap_h_func avg, regular, 1, \size
+do_8tap_h_func put, sharp,   2, \size
+do_8tap_h_func avg, sharp,   2, \size
+do_8tap_h_func put, smooth,  0, \size
+do_8tap_h_func avg, smooth,  0, \size
+.endm
+
+do_8tap_h_filters 64
+do_8tap_h_filters 32
+do_8tap_h_filters 16
+do_8tap_h_filters 8
+do_8tap_h_filters 4
+
+.ltorg
+
+@ Vertical filters
+
+@ Round, shift and saturate and store qreg1-2 over 4 lines
+.macro do_store4 qreg1, dreg1, qreg2, dreg2, tmp1, tmp2, type
+        vqrshrun.s16    \dreg1,  \qreg1, #7
+        vqrshrun.s16    \dreg2,  \qreg2, #7
+.ifc \type,avg
+        vld1.32         {\tmp1[]},   [r0,:32], r1
+        vld1.32         {\tmp2[]},   [r0,:32], r1
+        vld1.32         {\tmp1[1]},  [r0,:32], r1
+        vld1.32         {\tmp2[1]},  [r0,:32], r1
+        vrhadd.u8       \dreg1,  \dreg1,  \tmp1
+        vrhadd.u8       \dreg2,  \dreg2,  \tmp2
+        sub             r0,  r0,  r1, lsl #2
+.endif
+        vst1.32         {\dreg1[0]}, [r0,:32], r1
+        vst1.32         {\dreg2[0]}, [r0,:32], r1
+        vst1.32         {\dreg1[1]}, [r0,:32], r1
+        vst1.32         {\dreg2[1]}, [r0,:32], r1
+.endm
+
+@ Round, shift and saturate and store qreg1-4
+.macro do_store qreg1, dreg1, qreg2, dreg2, qreg3, dreg3, qreg4, dreg4, tmp1, tmp2, tmp3, tmp4, type
+        vqrshrun.s16    \dreg1,  \qreg1, #7
+        vqrshrun.s16    \dreg2,  \qreg2, #7
+        vqrshrun.s16    \dreg3,  \qreg3, #7
+        vqrshrun.s16    \dreg4,  \qreg4, #7
+.ifc \type,avg
+        vld1.8          {\tmp1},  [r0,:64], r1
+        vld1.8          {\tmp2},  [r0,:64], r1
+        vld1.8          {\tmp3},  [r0,:64], r1
+        vld1.8          {\tmp4},  [r0,:64], r1
+        vrhadd.u8       \dreg1,  \dreg1,  \tmp1
+        vrhadd.u8       \dreg2,  \dreg2,  \tmp2
+        vrhadd.u8       \dreg3,  \dreg3,  \tmp3
+        vrhadd.u8       \dreg4,  \dreg4,  \tmp4
+        sub             r0,  r0,  r1, lsl #2
+.endif
+        vst1.8          {\dreg1}, [r0,:64], r1
+        vst1.8          {\dreg2}, [r0,:64], r1
+        vst1.8          {\dreg3}, [r0,:64], r1
+        vst1.8          {\dreg4}, [r0,:64], r1
+.endm
+
+@ Evaluate the filter twice in parallel, from the inputs src1-src9 into dst1-dst2
+@ (src1-src8 into dst1, src2-src9 into dst2), adding idx2 separately
+@ at the end with saturation. Indices 0 and 7 always have negative or zero
+@ coefficients, so they can be accumulated into tmp1-tmp2 together with the
+@ largest coefficient.
+.macro convolve dst1, dst2, src1, src2, src3, src4, src5, src6, src7, src8, src9, idx1, idx2, tmp1, tmp2
+        vmul.s16        \dst1, \src2, d0[1]
+        vmul.s16        \dst2, \src3, d0[1]
+        vmul.s16        \tmp1, \src1, d0[0]
+        vmul.s16        \tmp2, \src2, d0[0]
+        vmla.s16        \dst1, \src3, d0[2]
+        vmla.s16        \dst2, \src4, d0[2]
+.if \idx1 == 3
+        vmla.s16        \dst1, \src4, d0[3]
+        vmla.s16        \dst2, \src5, d0[3]
+.else
+        vmla.s16        \dst1, \src5, d1[0]
+        vmla.s16        \dst2, \src6, d1[0]
+.endif
+        vmla.s16        \dst1, \src6, d1[1]
+        vmla.s16        \dst2, \src7, d1[1]
+        vmla.s16        \tmp1, \src8, d1[3]
+        vmla.s16        \tmp2, \src9, d1[3]
+        vmla.s16        \dst1, \src7, d1[2]
+        vmla.s16        \dst2, \src8, d1[2]
+.if \idx2 == 3
+        vmla.s16        \tmp1, \src4, d0[3]
+        vmla.s16        \tmp2, \src5, d0[3]
+.else
+        vmla.s16        \tmp1, \src5, d1[0]
+        vmla.s16        \tmp2, \src6, d1[0]
+.endif
+        vqadd.s16       \dst1, \dst1, \tmp1
+        vqadd.s16       \dst2, \dst2, \tmp2
+.endm
+
+@ Load pixels and extend them to 16 bit
+.macro loadl dst1, dst2, dst3, dst4
+        vld1.8          {d2}, [r2], r3
+        vld1.8          {d3}, [r2], r3
+        vld1.8          {d4}, [r2], r3
+.ifnb \dst4
+        vld1.8          {d5}, [r2], r3
+.endif
+        vmovl.u8        \dst1, d2
+        vmovl.u8        \dst2, d3
+        vmovl.u8        \dst3, d4
+.ifnb \dst4
+        vmovl.u8        \dst4, d5
+.endif
+.endm
+
+@ Instantiate a vertical filter function for filtering 8 pixels at a time.
+@ The height is passed in r4, the width in r5 and the filter coefficients
+@ in r12. idx2 is the index of the largest filter coefficient (3 or 4)
+@ and idx1 is the other one of them.
+.macro do_8tap_8v type, idx1, idx2
+function \type\()_8tap_8v_\idx1\idx2
+        sub             r2,  r2,  r3, lsl #1
+        sub             r2,  r2,  r3
+        vld1.16         {q0},  [r12, :128]
+1:
+        mov             r12,  r4
+
+        loadl           q5,  q6,  q7
+        loadl           q8,  q9,  q10, q11
+2:
+        loadl           q12, q13, q14, q15
+        convolve        q1,  q2,  q5,  q6,  q7,  q8,  q9,  q10, q11, q12, q13, \idx1, \idx2, q4,  q5
+        convolve        q3,  q4,  q7,  q8,  q9,  q10, q11, q12, q13, q14, q15, \idx1, \idx2, q5,  q6
+        do_store        q1,  d2,  q2,  d4,  q3,  d6,  q4,  d8,  d3,  d5,  d7,  d9,  \type
+
+        subs            r12, r12, #4
+        beq             8f
+
+        loadl           q4,  q5,  q6,  q7
+        convolve        q1,  q2,  q9,  q10, q11, q12, q13, q14, q15, q4,  q5,  \idx1, \idx2, q8,  q9
+        convolve        q3,  q8,  q11, q12, q13, q14, q15, q4,  q5,  q6,  q7,  \idx1, \idx2, q9,  q10
+        do_store        q1,  d2,  q2,  d4,  q3,  d6,  q8,  d16, d3,  d5,  d7,  d17, \type
+
+        subs            r12, r12, #4
+        beq             8f
+
+        loadl           q8,  q9,  q10, q11
+        convolve        q1,  q2,  q13, q14, q15, q4,  q5,  q6,  q7,  q8,  q9,  \idx1, \idx2, q12, q13
+        convolve        q3,  q12, q15, q4,  q5,  q6,  q7,  q8,  q9,  q10, q11, \idx1, \idx2, q13, q14
+        do_store        q1,  d2,  q2,  d4,  q3,  d6,  q12, d24, d3,  d5,  d7,  d25, \type
+
+        subs            r12, r12, #4
+        bne             2b
+
+8:
+        subs            r5,  r5,  #8
+        beq             9f
+        @ r0 -= h * dst_stride
+        mls             r0,  r1,  r4, r0
+        @ r2 -= h * src_stride
+        mls             r2,  r3,  r4, r2
+        @ r2 -= 8 * src_stride
+        sub             r2,  r2,  r3, lsl #3
+        @ r2 += 1 * src_stride
+        add             r2,  r2,  r3
+        add             r2,  r2,  #8
+        add             r0,  r0,  #8
+        b               1b
+9:
+        vpop            {q4-q7}
+        pop             {r4-r5}
+        bx              lr
+endfunc
+.endm
+
+do_8tap_8v put, 3, 4
+do_8tap_8v put, 4, 3
+do_8tap_8v avg, 3, 4
+do_8tap_8v avg, 4, 3
+
+@ Instantiate a vertical filter function for filtering a 4 pixels wide
+@ slice. The first half of the registers contain one row, while the second
+@ half of a register contains the second-next row (also stored in the first
+@ half of the register two steps ahead). The convolution does two outputs
+@ at a time; the output of q5-q12 into one, and q4-q13 into another one.
+@ The first half of first output is the first output row, the first half
+@ of the other output is the second output row. The second halves of the
+@ registers are rows 3 and 4.
+@ This only is designed to work for 4 or 8 output lines.
+.macro do_8tap_4v type, idx1, idx2
+function \type\()_8tap_4v_\idx1\idx2
+        sub             r2,  r2,  r3, lsl #1
+        sub             r2,  r2,  r3
+        vld1.16         {q0},  [r12, :128]
+
+        vld1.32         {d2[]},   [r2], r3
+        vld1.32         {d3[]},   [r2], r3
+        vld1.32         {d4[]},   [r2], r3
+        vld1.32         {d5[]},   [r2], r3
+        vld1.32         {d6[]},   [r2], r3
+        vld1.32         {d7[]},   [r2], r3
+        vext.8          d2,  d2,  d4,  #4
+        vld1.32         {d8[]},   [r2], r3
+        vext.8          d3,  d3,  d5,  #4
+        vld1.32         {d9[]},   [r2], r3
+        vmovl.u8        q5,  d2
+        vext.8          d4,  d4,  d6,  #4
+        vld1.32         {d28[]},  [r2], r3
+        vmovl.u8        q6,  d3
+        vext.8          d5,  d5,  d7,  #4
+        vld1.32         {d29[]},  [r2], r3
+        vmovl.u8        q7,  d4
+        vext.8          d6,  d6,  d8,  #4
+        vld1.32         {d30[]},  [r2], r3
+        vmovl.u8        q8,  d5
+        vext.8          d7,  d7,  d9,  #4
+        vmovl.u8        q9,  d6
+        vext.8          d8,  d8,  d28, #4
+        vmovl.u8        q10, d7
+        vext.8          d9,  d9,  d29, #4
+        vmovl.u8        q11, d8
+        vext.8          d28, d28, d30, #4
+        vmovl.u8        q12, d9
+        vmovl.u8        q13, d28
+
+        convolve        q1,  q2,  q5,  q6,  q7,  q8,  q9,  q10, q11, q12, q13, \idx1, \idx2, q4, q3
+        do_store4       q1,  d2,  q2,  d4,  d3,  d5,  \type
+        subs            r4,  r4,  #4
+        beq             9f
+
+        vld1.32         {d2[]},   [r2], r3
+        vld1.32         {d3[]},   [r2], r3
+        vext.8          d29, d29, d2,  #4
+        vext.8          d30, d30, d3,  #4
+        vld1.32         {d2[1]},  [r2], r3
+        vmovl.u8        q14, d29
+        vld1.32         {d3[1]},  [r2], r3
+        vmovl.u8        q15, d30
+        vmovl.u8        q5,  d2
+        vmovl.u8        q6,  d3
+
+        convolve        q1,  q2,  q9,  q10, q11, q12, q13, q14, q15, q5,  q6,  \idx1, \idx2, q4, q3
+        do_store4       q1,  d2,  q2,  d4,  d3,  d5,  \type
+
+9:
+        vpop            {q4-q7}
+        pop             {r4-r5}
+        bx              lr
+endfunc
+.endm
+
+do_8tap_4v put, 3, 4
+do_8tap_4v put, 4, 3
+do_8tap_4v avg, 3, 4
+do_8tap_4v avg, 4, 3
+
+.macro do_8tap_v_func type, filter, offset, size
+function ff_vp9_\type\()_\filter\()\size\()_v_neon, export=1
+        push            {r4-r5}
+        vpush           {q4-q7}
+        ldr             r4,  [sp, #72]
+        movrelx         r12, X(ff_vp9_subpel_filters), r5
+        ldr             r5,  [sp, #80]
+        add             r12, r12, 256*\offset
+        add             r12, r12, r5, lsl #4
+        cmp             r5,  #8
+        mov             r5,  #\size
+.if \size >= 8
+        bge             \type\()_8tap_8v_34
+        b               \type\()_8tap_8v_43
+.else
+        bge             \type\()_8tap_4v_34
+        b               \type\()_8tap_4v_43
+.endif
+endfunc
+.endm
+
+.macro do_8tap_v_filters size
+do_8tap_v_func put, regular, 1, \size
+do_8tap_v_func avg, regular, 1, \size
+do_8tap_v_func put, sharp,   2, \size
+do_8tap_v_func avg, sharp,   2, \size
+do_8tap_v_func put, smooth,  0, \size
+do_8tap_v_func avg, smooth,  0, \size
+.endm
+
+do_8tap_v_filters 64
+do_8tap_v_filters 32
+do_8tap_v_filters 16
+do_8tap_v_filters 8
+do_8tap_v_filters 4

libavcodec/vp9.c

@@ -2749,8 +2749,11 @@ static av_always_inline void mc_luma_unscaled(VP9Context *s, vp9_mc_func (*mc)[2
     // the longest loopfilter of the next sbrow
     th = (y + bh + 4 * !!my + 7) >> 6;
     ff_thread_await_progress(ref_frame, FFMAX(th, 0), 0);
+    // The arm _hv filters read one more row than what actually is
+    // needed, so switch to emulated edge one pixel sooner vertically
+    // (!!my * 5) than horizontally (!!mx * 4).
     if (x < !!mx * 3 || y < !!my * 3 ||
-        x + !!mx * 4 > w - bw || y + !!my * 4 > h - bh) {
+        x + !!mx * 4 > w - bw || y + !!my * 5 > h - bh) {
         s->vdsp.emulated_edge_mc(s->edge_emu_buffer,
                                  ref - !!my * 3 * ref_stride - !!mx * 3 * bytesperpixel,
                                  160, ref_stride,
@@ -2784,8 +2787,11 @@ static av_always_inline void mc_chroma_unscaled(VP9Context *s, vp9_mc_func (*mc)
     // the longest loopfilter of the next sbrow
     th = (y + bh + 4 * !!my + 7) >> (6 - s->ss_v);
     ff_thread_await_progress(ref_frame, FFMAX(th, 0), 0);
+    // The arm _hv filters read one more row than what actually is
+    // needed, so switch to emulated edge one pixel sooner vertically
+    // (!!my * 5) than horizontally (!!mx * 4).
     if (x < !!mx * 3 || y < !!my * 3 ||
-        x + !!mx * 4 > w - bw || y + !!my * 4 > h - bh) {
+        x + !!mx * 4 > w - bw || y + !!my * 5 > h - bh) {
         s->vdsp.emulated_edge_mc(s->edge_emu_buffer,
                                  ref_u - !!my * 3 * src_stride_u - !!mx * 3 * bytesperpixel,
                                  160, src_stride_u,
@@ -2871,7 +2877,10 @@ static av_always_inline void mc_luma_scaled(VP9Context *s, vp9_scaled_mc_func sm
     // the longest loopfilter of the next sbrow
     th = (y + refbh_m1 + 4 + 7) >> 6;
     ff_thread_await_progress(ref_frame, FFMAX(th, 0), 0);
-    if (x < 3 || y < 3 || x + 4 >= w - refbw_m1 || y + 4 >= h - refbh_m1) {
+    // The arm _hv filters read one more row than what actually is
+    // needed, so switch to emulated edge one pixel sooner vertically
+    // (y + 5 >= h - refbh_m1) than horizontally (x + 4 >= w - refbw_m1).
+    if (x < 3 || y < 3 || x + 4 >= w - refbw_m1 || y + 5 >= h - refbh_m1) {
         s->vdsp.emulated_edge_mc(s->edge_emu_buffer,
                                  ref - 3 * ref_stride - 3 * bytesperpixel,
                                  288, ref_stride,
@@ -2937,7 +2946,10 @@ static av_always_inline void mc_chroma_scaled(VP9Context *s, vp9_scaled_mc_func
     // the longest loopfilter of the next sbrow
     th = (y + refbh_m1 + 4 + 7) >> (6 - s->ss_v);
     ff_thread_await_progress(ref_frame, FFMAX(th, 0), 0);
-    if (x < 3 || y < 3 || x + 4 >= w - refbw_m1 || y + 4 >= h - refbh_m1) {
+    // The arm _hv filters read one more row than what actually is
+    // needed, so switch to emulated edge one pixel sooner vertically
+    // (y + 5 >= h - refbh_m1) than horizontally (x + 4 >= w - refbw_m1).
+    if (x < 3 || y < 3 || x + 4 >= w - refbw_m1 || y + 5 >= h - refbh_m1) {
         s->vdsp.emulated_edge_mc(s->edge_emu_buffer,
                                  ref_u - 3 * src_stride_u - 3 * bytesperpixel,
                                  288, src_stride_u,

libavcodec/vp9dsp.c

@@ -92,6 +92,7 @@ av_cold void ff_vp9dsp_init(VP9DSPContext *dsp, int bpp, int bitexact)
         ff_vp9dsp_init_12(dsp);
     }
 
+    if (ARCH_ARM) ff_vp9dsp_init_arm(dsp, bpp);
     if (ARCH_X86) ff_vp9dsp_init_x86(dsp, bpp, bitexact);
     if (ARCH_MIPS) ff_vp9dsp_init_mips(dsp, bpp);
 }

libavcodec/vp9dsp.h

@@ -129,6 +129,7 @@ void ff_vp9dsp_init_8(VP9DSPContext *dsp);
 void ff_vp9dsp_init_10(VP9DSPContext *dsp);
 void ff_vp9dsp_init_12(VP9DSPContext *dsp);
 
+void ff_vp9dsp_init_arm(VP9DSPContext *dsp, int bpp);
 void ff_vp9dsp_init_x86(VP9DSPContext *dsp, int bpp, int bitexact);
 void ff_vp9dsp_init_mips(VP9DSPContext *dsp, int bpp);