vc1: arm: Add NEON assembly

For:

ff_vc1_inv_trans_{8,4}x{8,4}_{dc_,}neon
ff_put_pixels8x8_neon
ff_put_vc1_mspel_mc{0,1,2,3}{0,1,2,3}_neon (except for 00)

Based on ARM assembly code in libavcodec/arm by Rob Clark and Mans
Rullgard.

Signed-off-by: Martin Storsjö <martin@martin.st>

7 files changed, 1334 insertions, 0 deletions

diff --git a/libavcodec/arm/Makefile b/libavcodec/arm/Makefile
index 201f897a61..277abd98ea 100644
--- a/libavcodec/arm/Makefile
+++ b/libavcodec/arm/Makefile
@@ -23,6 +23,7 @@ OBJS-$(CONFIG_HPELDSP)                 += arm/hpeldsp_init_arm.o        \
                                           arm/hpeldsp_arm.o
 OBJS-$(CONFIG_MPEGAUDIODSP)            += arm/mpegaudiodsp_init_arm.o
 OBJS-$(CONFIG_MPEGVIDEO)               += arm/mpegvideo_arm.o
+OBJS-$(CONFIG_VC1_DECODER)             += arm/vc1dsp_init_arm.o
 OBJS-$(CONFIG_VORBIS_DECODER)          += arm/vorbisdsp_init_arm.o
 OBJS-$(CONFIG_VP3DSP)                  += arm/vp3dsp_init_arm.o
 OBJS-$(CONFIG_VP6_DECODER)             += arm/vp6dsp_init_arm.o
@@ -88,6 +89,8 @@ NEON-OBJS-$(CONFIG_RDFT)               += arm/rdft_neon.o
 NEON-OBJS-$(CONFIG_RV30_DECODER)       += arm/rv34dsp_neon.o
 NEON-OBJS-$(CONFIG_RV40_DECODER)       += arm/rv34dsp_neon.o            \
                                           arm/rv40dsp_neon.o
+NEON-OBJS-$(CONFIG_VC1_DECODER)        += arm/vc1dsp_init_neon.o        \
+                                          arm/vc1dsp_neon.o
 NEON-OBJS-$(CONFIG_VORBIS_DECODER)     += arm/vorbisdsp_neon.o
 NEON-OBJS-$(CONFIG_VP3DSP)             += arm/vp3dsp_neon.o
 NEON-OBJS-$(CONFIG_VP6_DECODER)        += arm/vp6dsp_neon.o
diff --git a/libavcodec/arm/vc1dsp.h b/libavcodec/arm/vc1dsp.h
new file mode 100644
index 0000000000..30f059f28c
--- /dev/null
+++ b/libavcodec/arm/vc1dsp.h
@@ -0,0 +1,26 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_ARM_VC1DSP_H
+#define AVCODEC_ARM_VC1DSP_H
+
+#include "libavcodec/vc1dsp.h"
+
+void ff_vc1dsp_init_neon(VC1DSPContext *dsp);
+
+#endif /* AVCODEC_ARM_VC1DSP_H */
diff --git a/libavcodec/arm/vc1dsp_init_arm.c b/libavcodec/arm/vc1dsp_init_arm.c
new file mode 100644
index 0000000000..6d4eb79487
--- /dev/null
+++ b/libavcodec/arm/vc1dsp_init_arm.c
@@ -0,0 +1,32 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; 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/vc1dsp.h"
+#include "vc1dsp.h"
+
+av_cold void ff_vc1dsp_init_arm(VC1DSPContext *dsp)
+{
+    int cpu_flags = av_get_cpu_flags();
+
+    if (have_neon(cpu_flags))
+        ff_vc1dsp_init_neon(dsp);
+}
diff --git a/libavcodec/arm/vc1dsp_init_neon.c b/libavcodec/arm/vc1dsp_init_neon.c
new file mode 100644
index 0000000000..5cc65d7abc
--- /dev/null
+++ b/libavcodec/arm/vc1dsp_init_neon.c
@@ -0,0 +1,100 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; 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 "libavcodec/vc1dsp.h"
+#include "vc1dsp.h"
+
+void ff_vc1_inv_trans_8x8_neon(int16_t *block);
+void ff_vc1_inv_trans_4x8_neon(uint8_t *dest, int linesize, int16_t *block);
+void ff_vc1_inv_trans_8x4_neon(uint8_t *dest, int linesize, int16_t *block);
+void ff_vc1_inv_trans_4x4_neon(uint8_t *dest, int linesize, int16_t *block);
+
+void ff_vc1_inv_trans_8x8_dc_neon(uint8_t *dest, int linesize, int16_t *block);
+void ff_vc1_inv_trans_4x8_dc_neon(uint8_t *dest, int linesize, int16_t *block);
+void ff_vc1_inv_trans_8x4_dc_neon(uint8_t *dest, int linesize, int16_t *block);
+void ff_vc1_inv_trans_4x4_dc_neon(uint8_t *dest, int linesize, int16_t *block);
+
+void ff_put_pixels8x8_neon(uint8_t *block, const uint8_t *pixels,
+                           ptrdiff_t line_size, int rnd);
+
+void ff_put_vc1_mspel_mc10_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+void ff_put_vc1_mspel_mc20_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+void ff_put_vc1_mspel_mc30_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+
+void ff_put_vc1_mspel_mc01_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+void ff_put_vc1_mspel_mc02_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+void ff_put_vc1_mspel_mc03_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+
+void ff_put_vc1_mspel_mc11_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+void ff_put_vc1_mspel_mc12_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+void ff_put_vc1_mspel_mc13_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+
+void ff_put_vc1_mspel_mc21_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+void ff_put_vc1_mspel_mc22_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+void ff_put_vc1_mspel_mc23_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+
+void ff_put_vc1_mspel_mc31_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+void ff_put_vc1_mspel_mc32_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+void ff_put_vc1_mspel_mc33_neon(uint8_t *dst, const uint8_t *src,
+                                ptrdiff_t stride, int rnd);
+
+av_cold void ff_vc1dsp_init_neon(VC1DSPContext *dsp)
+{
+    dsp->vc1_inv_trans_8x8 = ff_vc1_inv_trans_8x8_neon;
+    dsp->vc1_inv_trans_4x8 = ff_vc1_inv_trans_4x8_neon;
+    dsp->vc1_inv_trans_8x4 = ff_vc1_inv_trans_8x4_neon;
+    dsp->vc1_inv_trans_4x4 = ff_vc1_inv_trans_4x4_neon;
+    dsp->vc1_inv_trans_8x8_dc = ff_vc1_inv_trans_8x8_dc_neon;
+    dsp->vc1_inv_trans_4x8_dc = ff_vc1_inv_trans_4x8_dc_neon;
+    dsp->vc1_inv_trans_8x4_dc = ff_vc1_inv_trans_8x4_dc_neon;
+    dsp->vc1_inv_trans_4x4_dc = ff_vc1_inv_trans_4x4_dc_neon;
+
+    dsp->put_vc1_mspel_pixels_tab[ 0] = ff_put_pixels8x8_neon;
+    dsp->put_vc1_mspel_pixels_tab[ 1] = ff_put_vc1_mspel_mc10_neon;
+    dsp->put_vc1_mspel_pixels_tab[ 2] = ff_put_vc1_mspel_mc20_neon;
+    dsp->put_vc1_mspel_pixels_tab[ 3] = ff_put_vc1_mspel_mc30_neon;
+    dsp->put_vc1_mspel_pixels_tab[ 4] = ff_put_vc1_mspel_mc01_neon;
+    dsp->put_vc1_mspel_pixels_tab[ 5] = ff_put_vc1_mspel_mc11_neon;
+    dsp->put_vc1_mspel_pixels_tab[ 6] = ff_put_vc1_mspel_mc21_neon;
+    dsp->put_vc1_mspel_pixels_tab[ 7] = ff_put_vc1_mspel_mc31_neon;
+    dsp->put_vc1_mspel_pixels_tab[ 8] = ff_put_vc1_mspel_mc02_neon;
+    dsp->put_vc1_mspel_pixels_tab[ 9] = ff_put_vc1_mspel_mc12_neon;
+    dsp->put_vc1_mspel_pixels_tab[10] = ff_put_vc1_mspel_mc22_neon;
+    dsp->put_vc1_mspel_pixels_tab[11] = ff_put_vc1_mspel_mc32_neon;
+    dsp->put_vc1_mspel_pixels_tab[12] = ff_put_vc1_mspel_mc03_neon;
+    dsp->put_vc1_mspel_pixels_tab[13] = ff_put_vc1_mspel_mc13_neon;
+    dsp->put_vc1_mspel_pixels_tab[14] = ff_put_vc1_mspel_mc23_neon;
+    dsp->put_vc1_mspel_pixels_tab[15] = ff_put_vc1_mspel_mc33_neon;
+}
diff --git a/libavcodec/arm/vc1dsp_neon.S b/libavcodec/arm/vc1dsp_neon.S
new file mode 100644
index 0000000000..d1b24cfc04
--- /dev/null
+++ b/libavcodec/arm/vc1dsp_neon.S
@@ -0,0 +1,1170 @@
+/*
+ * VC1 NEON optimisations
+ *
+ * Copyright (c) 2010 Rob Clark <rob@ti.com>
+ * Copyright (c) 2011 Mans Rullgard <mans@mansr.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/arm/asm.S"
+#include "neon.S"
+
+@ Transpose rows into columns of a matrix of 16-bit elements. For 4x4, pass
+@ double-word registers, for 8x4, pass quad-word registers.
+.macro transpose16 r0, r1, r2, r3
+        @ At this point:
+        @   row[0]  r0
+        @   row[1]  r1
+        @   row[2]  r2
+        @   row[3]  r3
+
+        vtrn.16         \r0,  \r1         @ first and second row
+        vtrn.16         \r2,  \r3         @ third and fourth row
+        vtrn.32         \r0,  \r2         @ first and third row
+        vtrn.32         \r1,  \r3         @ second and fourth row
+
+        @ At this point, if registers are quad-word:
+        @   column[0]   d0
+        @   column[1]   d2
+        @   column[2]   d4
+        @   column[3]   d6
+        @   column[4]   d1
+        @   column[5]   d3
+        @   column[6]   d5
+        @   column[7]   d7
+
+        @ At this point, if registers are double-word:
+        @   column[0]   d0
+        @   column[1]   d1
+        @   column[2]   d2
+        @   column[3]   d3
+.endm
+
+@ ff_vc1_inv_trans_{4,8}x{4,8}_neon and overflow: The input values in the file
+@ are supposed to be in a specific range as to allow for 16-bit math without
+@ causing overflows, but sometimes the input values are just big enough to
+@ barely cause overflow in vadd instructions like:
+@
+@   vadd.i16  q0, q8, q10
+@   vshr.s16  q0, q0, #\rshift
+@
+@ To prevent these borderline cases from overflowing, we just need one more
+@ bit of precision, which is accomplished by replacing the sequence above with:
+@
+@   vhadd.s16 q0, q8, q10
+@   vshr.s16  q0, q0, #(\rshift -1)
+@
+@ This works because vhadd is a single instruction that adds, then shifts to
+@ the right once, all before writing the result to the destination register.
+@
+@ Even with this workaround, there were still some files that caused overflows
+@ in ff_vc1_inv_trans_8x8_neon. See the comments in ff_vc1_inv_trans_8x8_neon
+@ for the additional workaround.
+
+@ Takes 4 columns of 8 values each and operates on it. Modeled after the first
+@ for loop in vc1_inv_trans_4x8_c.
+@ Input columns: q0 q1 q2 q3
+@ Output columns: q0 q1 q2 q3
+@ Trashes: r12 q8 q9 q10 q11 q12 q13
+.macro vc1_inv_trans_4x8_helper add rshift
+        @ Compute temp1, temp2 and setup scalar #17, #22, #10
+        vadd.i16        q12,   q0,  q2              @ temp1 = src[0] + src[2]
+        movw            r12,   #17
+        vsub.i16        q13,   q0,  q2              @ temp2 = src[0] - src[2]
+        movt            r12,   #22
+        vmov.32         d0[0], r12
+        movw            r12,   #10
+        vmov.16         d1[0], r12
+
+        vmov.i16        q8,  #\add                  @ t1 will accumulate here
+        vmov.i16        q9,  #\add                  @ t2 will accumulate here
+
+        vmul.i16        q10, q1,  d0[1]             @ t3 = 22 * (src[1])
+        vmul.i16        q11, q3,  d0[1]             @ t4 = 22 * (src[3])
+
+        vmla.i16        q8,  q12, d0[0]             @ t1 = 17 * (temp1) + 4
+        vmla.i16        q9,  q13, d0[0]             @ t2 = 17 * (temp2) + 4
+
+        vmla.i16        q10, q3,  d1[0]             @ t3 += 10 * src[3]
+        vmls.i16        q11, q1,  d1[0]             @ t4 -= 10 * src[1]
+
+        vhadd.s16       q0,  q8,  q10               @ dst[0] = (t1 + t3) >> 1
+        vhsub.s16       q3,  q8,  q10               @ dst[3] = (t1 - t3) >> 1
+        vhsub.s16       q1,  q9,  q11               @ dst[1] = (t2 - t4) >> 1
+        vhadd.s16       q2,  q9,  q11               @ dst[2] = (t2 + t4) >> 1
+
+        @ Halving add/sub above already did one shift
+        vshr.s16        q0,  q0,  #(\rshift - 1)    @ dst[0] >>= (rshift - 1)
+        vshr.s16        q3,  q3,  #(\rshift - 1)    @ dst[3] >>= (rshift - 1)
+        vshr.s16        q1,  q1,  #(\rshift - 1)    @ dst[1] >>= (rshift - 1)
+        vshr.s16        q2,  q2,  #(\rshift - 1)    @ dst[2] >>= (rshift - 1)
+.endm
+
+@ Takes 8 columns of 4 values each and operates on it. Modeled after the second
+@ for loop in vc1_inv_trans_4x8_c.
+@ Input columns: d0 d2 d4 d6 d1 d3 d5 d7
+@ Output columns: d16 d17 d18 d19 d21 d20 d23 d22
+@ Trashes all NEON registers (and r12) except for: q4 q5 q6 q7
+.macro vc1_inv_trans_8x4_helper add add1beforeshift rshift
+        @ At this point:
+        @   src[0]      d0 overwritten later
+        @   src[8]      d2
+        @   src[16]     d4 overwritten later
+        @   src[24]     d6
+        @   src[32]     d1 overwritten later
+        @   src[40]     d3
+        @   src[48]     d5 overwritten later
+        @   src[56]     d7
+
+        movw            r12,   #12
+        vmov.i16        q14,   #\add            @ t1|t2 will accumulate here
+        movt            r12,   #6
+
+        vadd.i16        d20,   d0,  d1          @ temp1 = src[0] + src[32]
+        vsub.i16        d21,   d0,  d1          @ temp2 = src[0] - src[32]
+        vmov.i32        d0[0], r12              @ 16-bit: d0[0] = #12, d0[1] = #6
+
+        vshl.i16        q15,   q2,  #4          @ t3|t4 = 16 * (src[16]|src[48])
+        vswp            d4,    d5               @ q2 = src[48]|src[16]
+        vmla.i16        q14,   q10, d0[0]       @ t1|t2 = 12 * (temp1|temp2) + 64
+        movw            r12,   #15
+        movt            r12,   #9
+        vmov.i32        d0[1], r12              @ 16-bit: d0[2] = #15, d0[3] = #9
+        vneg.s16        d31,   d31              @ t4 = -t4
+        vmla.i16        q15,   q2,  d0[1]       @ t3|t4 += 6 * (src[48]|src[16])
+
+        @ At this point:
+        @   d0[2]   #15
+        @   d0[3]   #9
+        @   q1      src[8]|src[40]
+        @   q3      src[24]|src[56]
+        @   q14     old t1|t2
+        @   q15     old t3|t4
+
+        vshl.i16        q8,  q1,  #4            @ t1|t2 = 16 * (src[8]|src[40])
+        vswp            d2,  d3                 @ q1 = src[40]|src[8]
+        vshl.i16        q12, q3,  #4            @ temp3a|temp4a = 16 * src[24]|src[56]
+        vswp            d6,  d7                 @ q3 = src[56]|src[24]
+        vshl.i16        q13, q1,  #2            @ temp3b|temp4b = 4 * (src[40]|src[8])
+        vshl.i16        q2,  q3,  #2            @ temp1|temp2 = 4 * (src[56]|src[24])
+        vswp            d3,  d6                 @ q1 = src[40]|src[56], q3 = src[8]|src[24]
+        vsub.i16        q9,  q13, q12           @ t3|t4 = - (temp3a|temp4a) + (temp3b|temp4b)
+        vadd.i16        q8,  q8,  q2            @ t1|t2 += temp1|temp2
+        vmul.i16        q12, q3,  d0[3]         @ temp3|temp4 = 9 * src[8]|src[24]
+        vmla.i16        q8,  q1,  d0[3]         @ t1|t2 += 9 * (src[40]|src[56])
+        vswp            d6,  d7                 @ q3 = src[24]|src[8]
+        vswp            d2,  d3                 @ q1 = src[56]|src[40]
+
+        vsub.i16        q11, q14, q15           @ t8|t7 = old t1|t2 - old t3|t4
+        vadd.i16        q10, q14, q15           @ t5|t6 = old t1|t2 + old t3|t4
+  .if \add1beforeshift
+        vmov.i16        q15, #1
+  .endif
+
+        vadd.i16        d18, d18, d24           @ t3 += temp3
+        vsub.i16        d19, d19, d25           @ t4 -= temp4
+
+        vswp            d22, d23                @ q11 = t7|t8
+
+        vneg.s16        d17, d17                @ t2 = -t2
+        vmla.i16        q9,  q1,  d0[2]         @ t3|t4 += 15 * src[56]|src[40]
+        vmla.i16        q8,  q3,  d0[2]         @ t1|t2 += 15 * src[24]|src[8]
+
+        @ At this point:
+        @   t1  d16
+        @   t2  d17
+        @   t3  d18
+        @   t4  d19
+        @   t5  d20
+        @   t6  d21
+        @   t7  d22
+        @   t8  d23
+        @   #1  q15
+
+  .if \add1beforeshift
+        vadd.i16        q3,  q15, q10           @ line[7,6] = t5|t6 + 1
+        vadd.i16        q2,  q15, q11           @ line[5,4] = t7|t8 + 1
+  .endif
+
+        @ Sometimes this overflows, so to get one additional bit of precision, use
+        @ a single instruction that both adds and shifts right (halving).
+        vhadd.s16       q1,  q9,  q11           @ line[2,3] = (t3|t4 + t7|t8) >> 1
+        vhadd.s16       q0,  q8,  q10           @ line[0,1] = (t1|t2 + t5|t6) >> 1
+  .if \add1beforeshift
+        vhsub.s16       q2,  q2,  q9            @ line[5,4] = (t7|t8 - t3|t4 + 1) >> 1
+        vhsub.s16       q3,  q3,  q8            @ line[7,6] = (t5|t6 - t1|t2 + 1) >> 1
+  .else
+        vhsub.s16       q2,  q11, q9            @ line[5,4] = (t7|t8 - t3|t4) >> 1
+        vhsub.s16       q3,  q10, q8            @ line[7,6] = (t5|t6 - t1|t2) >> 1
+  .endif
+
+        vshr.s16        q9,  q1,  #(\rshift - 1)    @ one shift is already done by vhadd/vhsub above
+        vshr.s16        q8,  q0,  #(\rshift - 1)
+        vshr.s16        q10, q2,  #(\rshift - 1)
+        vshr.s16        q11, q3,  #(\rshift - 1)
+
+        @ At this point:
+        @   dst[0]   d16
+        @   dst[1]   d17
+        @   dst[2]   d18
+        @   dst[3]   d19
+        @   dst[4]   d21
+        @   dst[5]   d20
+        @   dst[6]   d23
+        @   dst[7]   d22
+.endm
+
+@ This is modeled after the first and second for loop in vc1_inv_trans_8x8_c.
+@ Input columns:  q8, q9, q10, q11, q12, q13, q14, q15
+@ Output columns: q8, q9, q10, q11, q12, q13, q14, q15
+@ Trashes all NEON registers (and r12) except for: q4 q5 q6 q7
+.macro vc1_inv_trans_8x8_helper add add1beforeshift rshift
+        @ This actually computes half of t1, t2, t3, t4, as explained below
+        @ near `tNhalf`.
+        vmov.i16        q0,    #(6 / 2)         @ q0 = #6/2
+        vshl.i16        q1,    q10, #3          @ t3 = 16/2 * src[16]
+        vshl.i16        q3,    q14, #3          @ temp4 = 16/2 * src[48]
+        vmul.i16        q2,    q10, q0          @ t4 = 6/2 * src[16]
+        vmla.i16        q1,    q14, q0          @ t3 += 6/2 * src[48]
+        @ unused: q0, q10, q14
+        vmov.i16        q0,    #(12 / 2)        @ q0 = #12/2
+        vadd.i16        q10,   q8,  q12         @ temp1 = src[0] + src[32]
+        vsub.i16        q14,   q8,  q12         @ temp2 = src[0] - src[32]
+        @ unused: q8, q12
+        vmov.i16        q8,    #(\add / 2)      @ t1 will accumulate here
+        vmov.i16        q12,   #(\add / 2)      @ t2 will accumulate here
+        movw            r12,   #15
+        vsub.i16        q2,    q2,  q3          @ t4 = 6/2 * src[16] - 16/2 * src[48]
+        movt            r12,   #9
+        @ unused: q3
+        vmla.i16        q8,    q10, q0          @ t1 = 12/2 * temp1 + add
+        vmla.i16        q12,   q14, q0          @ t2 = 12/2 * temp2 + add
+        vmov.i32        d0[0], r12
+        @ unused: q3, q10, q14
+
+        @ At this point:
+        @   q0          d0=#15|#9
+        @   q1  old t3
+        @   q2  old t4
+        @   q3
+        @   q8  old t1
+        @   q9          src[8]
+        @   q10
+        @   q11         src[24]
+        @   q12 old t2
+        @   q13         src[40]
+        @   q14
+        @   q15         src[56]
+
+        @ unused: q3, q10, q14
+        movw            r12,   #16
+        vshl.i16        q3,    q9,  #4          @ t1 = 16 * src[8]
+        movt            r12,   #4
+        vshl.i16        q10,   q9,  #2          @ t4 = 4 * src[8]
+        vmov.i32        d1[0], r12
+        vmul.i16        q14,   q9,  d0[0]       @ t2 = 15 * src[8]
+        vmul.i16        q9,    q9,  d0[1]       @ t3 = 9 * src[8]
+        @ unused: none
+        vmla.i16        q3,    q11, d0[0]       @ t1 += 15 * src[24]
+        vmls.i16        q10,   q11, d0[1]       @ t4 -= 9 * src[24]
+        vmls.i16        q14,   q11, d1[1]       @ t2 -= 4 * src[24]
+        vmls.i16        q9,    q11, d1[0]       @ t3 -= 16 * src[24]
+        @ unused: q11
+        vmla.i16        q3,    q13, d0[1]       @ t1 += 9 * src[40]
+        vmla.i16        q10,   q13, d0[0]       @ t4 += 15 * src[40]
+        vmls.i16        q14,   q13, d1[0]       @ t2 -= 16 * src[40]
+        vmla.i16        q9,    q13, d1[1]       @ t3 += 4 * src[40]
+        @ unused: q11, q13
+
+        @ Compute t5, t6, t7, t8 from old t1, t2, t3, t4. Actually, it computes
+        @ half of t5, t6, t7, t8 since t1, t2, t3, t4 are halved.
+        vadd.i16        q11,   q8,  q1          @ t5 = t1 + t3
+        vsub.i16        q1,    q8,  q1          @ t8 = t1 - t3
+        vadd.i16        q13,   q12, q2          @ t6 = t2 + t4
+        vsub.i16        q2,    q12, q2          @ t7 = t2 - t4
+        @ unused: q8, q12
+
+  .if \add1beforeshift
+        vmov.i16        q12,   #1
+  .endif
+
+        @ unused: q8
+        vmla.i16        q3,    q15, d1[1]       @ t1 += 4 * src[56]
+        vmls.i16        q14,   q15, d0[1]       @ t2 -= 9 * src[56]
+        vmla.i16        q9,    q15, d0[0]       @ t3 += 15 * src[56]
+        vmls.i16        q10,   q15, d1[0]       @ t4 -= 16 * src[56]
+        @ unused: q0, q8, q15
+
+        @ At this point:
+        @   t1      q3
+        @   t2      q14
+        @   t3      q9
+        @   t4      q10
+        @   t5half  q11
+        @   t6half  q13
+        @   t7half  q2
+        @   t8half  q1
+        @   #1      q12
+        @
+        @ tNhalf is half of the value of tN (as described in vc1_inv_trans_8x8_c).
+        @ This is done because sometimes files have input that causes tN + tM to
+        @ overflow. To avoid this overflow, we compute tNhalf, then compute
+        @ tNhalf + tM (which doesn't overflow), and then we use vhadd to compute
+        @ (tNhalf + (tNhalf + tM)) >> 1 which does not overflow because it is
+        @ one instruction.
+
+        @ For each pair of tN and tM, do:
+        @   lineA = t5half + t1
+        @   if add1beforeshift:  t1 -= 1
+        @   lineA = (t5half + lineA) >> 1
+        @   lineB = t5half - t1
+        @   lineB = (t5half + lineB) >> 1
+        @   lineA >>= rshift - 1
+        @   lineB >>= rshift - 1
+
+        vadd.i16        q8,  q11, q3                @ q8 = t5half + t1
+  .if \add1beforeshift
+        vsub.i16        q3,  q3,  q12               @ q3 = t1 - 1
+  .endif
+
+        vadd.i16        q0,  q13, q14               @ q0  = t6half + t2
+  .if \add1beforeshift
+        vsub.i16        q14, q14, q12               @ q14 = t2 - 1
+  .endif
+
+        vadd.i16        q15, q2,  q9                @ q15 = t7half + t3
+  .if \add1beforeshift
+        vsub.i16        q9,  q9,  q12               @ q9  = t3 - 1
+  .endif
+        @ unused: none
+
+        vhadd.s16       q8,  q11, q8                @ q8  = (t5half + t5half + t1) >> 1
+        vsub.i16        q3,  q11, q3                @ q3  = t5half - t1 + 1
+
+        vhadd.s16       q0,  q13, q0                @ q0  = (t6half + t6half + t2) >> 1
+        vsub.i16        q14, q13, q14               @ q14 = t6half - t2 + 1
+
+        vhadd.s16       q15, q2,  q15               @ q15 = (t7half + t7half + t3) >> 1
+        vsub.i16        q9,  q2,  q9                @ q9  = t7half - t3 + 1
+
+        vhadd.s16       q3,  q11, q3                @ q3  = (t5half + t5half - t1 + 1) >> 1
+        @ unused: q11
+
+        vadd.i16        q11, q1,  q10               @ q11 = t8half + t4
+  .if \add1beforeshift
+        vsub.i16        q10, q10, q12               @ q10 = t4 - 1
+  .endif
+        @ unused: q12
+
+        vhadd.s16       q14, q13, q14               @ q14 = (t6half + t6half - t2 + 1) >> 1
+        @ unused: q12, q13
+        vhadd.s16       q13, q2,  q9                @ q9  = (t7half + t7half - t3 + 1) >> 1
+        @ unused: q12, q2, q9
+
+        vsub.i16        q10, q1,  q10               @ q10 = t8half - t4 + 1
+        vhadd.s16       q11, q1,  q11               @ q11 = (t8half + t8half + t4) >> 1
+
+        vshr.s16        q8,  q8,  #(\rshift - 1)    @ q8  = line[0]
+        vhadd.s16       q12, q1,  q10               @ q12 = (t8half + t8half - t4 + 1) >> 1
+        vshr.s16        q9,  q0,  #(\rshift - 1)    @ q9  = line[1]
+        vshr.s16        q10, q15, #(\rshift - 1)    @ q10 = line[2]
+        vshr.s16        q11, q11, #(\rshift - 1)    @ q11 = line[3]
+        vshr.s16        q12, q12, #(\rshift - 1)    @ q12 = line[4]
+        vshr.s16        q13, q13, #(\rshift - 1)    @ q13 = line[5]
+        vshr.s16        q14, q14, #(\rshift - 1)    @ q14 = line[6]
+        vshr.s16        q15, q3,  #(\rshift - 1)    @ q15 = line[7]
+.endm
+
+@ (int16_t *block [r0])
+function ff_vc1_inv_trans_8x8_neon, export=1
+        vld1.64         {q8-q9},   [r0,:128]!
+        vld1.64         {q10-q11}, [r0,:128]!
+        vld1.64         {q12-q13}, [r0,:128]!
+        vld1.64         {q14-q15}, [r0,:128]
+        sub             r0, r0, #(16 * 2 * 3)   @ restore r0
+
+        @ At this point:
+        @   src[0]  q8
+        @   src[8]  q9
+        @   src[16] q10
+        @   src[24] q11
+        @   src[32] q12
+        @   src[40] q13
+        @   src[48] q14
+        @   src[56] q15
+
+        vc1_inv_trans_8x8_helper add=4 add1beforeshift=0 rshift=3
+
+        @ Transpose result matrix of 8x8
+        swap4           d17, d19, d21, d23, d24, d26, d28, d30
+        transpose16_4x4 q8,  q9,  q10, q11, q12, q13, q14, q15
+
+        vc1_inv_trans_8x8_helper add=64 add1beforeshift=1 rshift=7
+
+        vst1.64         {q8-q9},   [r0,:128]!
+        vst1.64         {q10-q11}, [r0,:128]!
+        vst1.64         {q12-q13}, [r0,:128]!
+        vst1.64         {q14-q15}, [r0,:128]
+
+        bx              lr
+endfunc
+
+@ (uint8_t *dest [r0], int linesize [r1], int16_t *block [r2])
+function ff_vc1_inv_trans_8x4_neon, export=1
+        vld1.64         {q0-q1}, [r2,:128]!     @ load 8 * 4 * 2 = 64 bytes / 16 bytes per quad = 4 quad registers
+        vld1.64         {q2-q3}, [r2,:128]
+
+        transpose16     q0 q1 q2 q3             @ transpose rows to columns
+
+        @ At this point:
+        @   src[0]   d0
+        @   src[1]   d2
+        @   src[2]   d4
+        @   src[3]   d6
+        @   src[4]   d1
+        @   src[5]   d3
+        @   src[6]   d5
+        @   src[7]   d7
+
+        vc1_inv_trans_8x4_helper    add=4 add1beforeshift=0 rshift=3
+
+        @ Move output to more standardized registers
+        vmov        d0, d16
+        vmov        d2, d17
+        vmov        d4, d18
+        vmov        d6, d19
+        vmov        d1, d21
+        vmov        d3, d20
+        vmov        d5, d23
+        vmov        d7, d22
+
+        @ At this point:
+        @   dst[0]   d0
+        @   dst[1]   d2
+        @   dst[2]   d4
+        @   dst[3]   d6
+        @   dst[4]   d1
+        @   dst[5]   d3
+        @   dst[6]   d5
+        @   dst[7]   d7
+
+        transpose16     q0 q1 q2 q3   @ turn columns into rows
+
+        @ At this point:
+        @   row[0] q0
+        @   row[1] q1
+        @   row[2] q2
+        @   row[3] q3
+
+        vc1_inv_trans_4x8_helper    add=64 rshift=7
+
+        @ At this point:
+        @   line[0].l   d0
+        @   line[0].h   d1
+        @   line[1].l   d2
+        @   line[1].h   d3
+        @   line[2].l   d4
+        @   line[2].h   d5
+        @   line[3].l   d6
+        @   line[3].h   d7
+
+        @ unused registers: q12, q13, q14, q15
+
+        vld1.64         {d28}, [r0,:64], r1     @ read dest
+        vld1.64         {d29}, [r0,:64], r1
+        vld1.64         {d30}, [r0,:64], r1
+        vld1.64         {d31}, [r0,:64], r1
+        sub             r0,  r0,  r1, lsl #2    @ restore original r0 value
+
+        vaddw.u8        q0,  q0,  d28           @ line[0] += dest[0]
+        vaddw.u8        q1,  q1,  d29           @ line[1] += dest[1]
+        vaddw.u8        q2,  q2,  d30           @ line[2] += dest[2]
+        vaddw.u8        q3,  q3,  d31           @ line[3] += dest[3]
+
+        vqmovun.s16     d0,  q0                 @ line[0]
+        vqmovun.s16     d1,  q1                 @ line[1]
+        vqmovun.s16     d2,  q2                 @ line[2]
+        vqmovun.s16     d3,  q3                 @ line[3]
+
+        vst1.64         {d0},  [r0,:64], r1     @ write dest
+        vst1.64         {d1},  [r0,:64], r1
+        vst1.64         {d2},  [r0,:64], r1
+        vst1.64         {d3},  [r0,:64]
+
+        bx              lr
+endfunc
+
+@ (uint8_t *dest [r0], int linesize [r1], int16_t *block [r2])
+function ff_vc1_inv_trans_4x8_neon, export=1
+        mov             r12, #(8 * 2)  @ 8 elements per line, each element 2 bytes
+        vld4.16         {d0[],  d2[],  d4[],  d6[]},  [r2,:64], r12     @ read each column into a q register
+        vld4.16         {d0[1], d2[1], d4[1], d6[1]}, [r2,:64], r12
+        vld4.16         {d0[2], d2[2], d4[2], d6[2]}, [r2,:64], r12
+        vld4.16         {d0[3], d2[3], d4[3], d6[3]}, [r2,:64], r12
+        vld4.16         {d1[],  d3[],  d5[],  d7[]},  [r2,:64], r12
+        vld4.16         {d1[1], d3[1], d5[1], d7[1]}, [r2,:64], r12
+        vld4.16         {d1[2], d3[2], d5[2], d7[2]}, [r2,:64], r12
+        vld4.16         {d1[3], d3[3], d5[3], d7[3]}, [r2,:64]
+
+        vc1_inv_trans_4x8_helper    add=4 rshift=3
+
+        @ At this point:
+        @   dst[0] = q0
+        @   dst[1] = q1
+        @   dst[2] = q2
+        @   dst[3] = q3
+
+        transpose16     q0 q1 q2 q3     @ Transpose rows (registers) into columns
+
+        vc1_inv_trans_8x4_helper    add=64 add1beforeshift=1 rshift=7
+
+        vld1.32         {d28[]},  [r0,:32], r1  @ read dest
+        vld1.32         {d28[1]}, [r0,:32], r1
+        vld1.32         {d29[]},  [r0,:32], r1
+        vld1.32         {d29[1]}, [r0,:32], r1
+
+        vld1.32         {d30[]},  [r0,:32], r1
+        vld1.32         {d30[0]}, [r0,:32], r1
+        vld1.32         {d31[]},  [r0,:32], r1
+        vld1.32         {d31[0]}, [r0,:32], r1
+        sub             r0,  r0,  r1, lsl #3    @ restore original r0 value
+
+        vaddw.u8        q8,  q8,  d28           @ line[0,1] += dest[0,1]
+        vaddw.u8        q9,  q9,  d29           @ line[2,3] += dest[2,3]
+        vaddw.u8        q10, q10, d30           @ line[5,4] += dest[5,4]
+        vaddw.u8        q11, q11, d31           @ line[7,6] += dest[7,6]
+
+        vqmovun.s16     d16, q8                 @ clip(line[0,1])
+        vqmovun.s16     d18, q9                 @ clip(line[2,3])
+        vqmovun.s16     d20, q10                @ clip(line[5,4])
+        vqmovun.s16     d22, q11                @ clip(line[7,6])
+
+        vst1.32         {d16[0]}, [r0,:32], r1  @ write dest
+        vst1.32         {d16[1]}, [r0,:32], r1
+        vst1.32         {d18[0]}, [r0,:32], r1
+        vst1.32         {d18[1]}, [r0,:32], r1
+
+        vst1.32         {d20[1]}, [r0,:32], r1
+        vst1.32         {d20[0]}, [r0,:32], r1
+        vst1.32         {d22[1]}, [r0,:32], r1
+        vst1.32         {d22[0]}, [r0,:32]
+
+        bx              lr
+endfunc
+
+@ Setup constants in registers which are used by vc1_inv_trans_4x4_helper
+.macro vc1_inv_trans_4x4_helper_setup
+        vmov.i16        q13, #17
+        vmov.i16        q14, #22
+        vmov.i16        d30, #10                @ only need double-word, not quad-word
+.endm
+
+@ This is modeled after the first for loop in vc1_inv_trans_4x4_c.
+.macro vc1_inv_trans_4x4_helper add rshift
+        vmov.i16        q2,  #\add              @ t1|t2 will accumulate here
+
+        vadd.i16        d16, d0,  d1            @ temp1 = src[0] + src[2]
+        vsub.i16        d17, d0,  d1            @ temp2 = src[0] - src[2]
+        vmul.i16        q3,  q14, q1            @ t3|t4 = 22 * (src[1]|src[3])
+        vmla.i16        q2,  q13, q8            @ t1|t2 = 17 * (temp1|temp2) + add
+        vmla.i16        d6,  d30, d3            @ t3 += 10 * src[3]
+        vmls.i16        d7,  d30, d2            @ t4 -= 10 * src[1]
+
+        vadd.i16        q0,  q2,  q3            @ dst[0,2] = (t1|t2 + t3|t4)
+        vsub.i16        q1,  q2,  q3            @ dst[3,1] = (t1|t2 - t3|t4)
+        vshr.s16        q0,  q0,  #\rshift      @ dst[0,2] >>= rshift
+        vshr.s16        q1,  q1,  #\rshift      @ dst[3,1] >>= rshift
+.endm
+
+@ (uint8_t *dest [r0], int linesize [r1], int16_t *block [r2])
+function ff_vc1_inv_trans_4x4_neon, export=1
+        mov             r12, #(8 * 2)  @ 8 elements per line, each element 2 bytes
+        vld4.16         {d0[],  d1[],  d2[],  d3[]},  [r2,:64], r12     @ read each column into a register
+        vld4.16         {d0[1], d1[1], d2[1], d3[1]}, [r2,:64], r12
+        vld4.16         {d0[2], d1[2], d2[2], d3[2]}, [r2,:64], r12
+        vld4.16         {d0[3], d1[3], d2[3], d3[3]}, [r2,:64]
+
+        vswp            d1,  d2         @ so that we can later access column 1 and column 3 as a single q1 register
+
+        vc1_inv_trans_4x4_helper_setup
+
+        @ At this point:
+        @   src[0] = d0
+        @   src[1] = d2
+        @   src[2] = d1
+        @   src[3] = d3
+
+        vc1_inv_trans_4x4_helper add=4 rshift=3      @ compute t1, t2, t3, t4 and combine them into dst[0-3]
+
+        @ At this point:
+        @   dst[0] = d0
+        @   dst[1] = d3
+        @   dst[2] = d1
+        @   dst[3] = d2
+
+        transpose16     d0 d3 d1 d2     @ Transpose rows (registers) into columns
+
+        @ At this point:
+        @   src[0]  = d0
+        @   src[8]  = d3
+        @   src[16] = d1
+        @   src[24] = d2
+
+        vswp            d2,  d3         @ so that we can later access column 1 and column 3 in order as a single q1 register
+
+        @ At this point:
+        @   src[0]  = d0
+        @   src[8]  = d2
+        @   src[16] = d1
+        @   src[24] = d3
+
+        vc1_inv_trans_4x4_helper add=64 rshift=7              @ compute t1, t2, t3, t4 and combine them into dst[0-3]
+
+        @ At this point:
+        @   line[0] = d0
+        @   line[1] = d3
+        @   line[2] = d1
+        @   line[3] = d2
+
+        vld1.32         {d18[]},  [r0,:32], r1  @ read dest
+        vld1.32         {d19[]},  [r0,:32], r1
+        vld1.32         {d18[1]}, [r0,:32], r1
+        vld1.32         {d19[0]}, [r0,:32], r1
+        sub             r0,  r0,  r1, lsl #2    @ restore original r0 value
+
+        vaddw.u8        q0,  q0,  d18           @ line[0,2] += dest[0,2]
+        vaddw.u8        q1,  q1,  d19           @ line[3,1] += dest[3,1]
+
+        vqmovun.s16     d0,  q0                 @ clip(line[0,2])
+        vqmovun.s16     d1,  q1                 @ clip(line[3,1])
+
+        vst1.32         {d0[0]},  [r0,:32], r1  @ write dest
+        vst1.32         {d1[1]},  [r0,:32], r1
+        vst1.32         {d0[1]},  [r0,:32], r1
+        vst1.32         {d1[0]},  [r0,:32]
+
+        bx              lr
+endfunc
+
+@ The absolute value of multiplication constants from vc1_mspel_filter and vc1_mspel_{ver,hor}_filter_16bits.
+@ The sign is embedded in the code below that carries out the multiplication (mspel_filter{,.16}).
+#define MSPEL_MODE_1_MUL_CONSTANTS  4 53 18 3
+#define MSPEL_MODE_2_MUL_CONSTANTS  1 9  9  1
+#define MSPEL_MODE_3_MUL_CONSTANTS  3 18 53 4
+
+@ These constants are from reading the source code of vc1_mspel_mc and determining the value that
+@ is added to `rnd` to result in the variable `r`, and the value of the variable `shift`.
+#define MSPEL_MODES_11_ADDSHIFT_CONSTANTS   15 5
+#define MSPEL_MODES_12_ADDSHIFT_CONSTANTS   3  3
+#define MSPEL_MODES_13_ADDSHIFT_CONSTANTS   15 5
+#define MSPEL_MODES_21_ADDSHIFT_CONSTANTS   MSPEL_MODES_12_ADDSHIFT_CONSTANTS
+#define MSPEL_MODES_22_ADDSHIFT_CONSTANTS   0  1
+#define MSPEL_MODES_23_ADDSHIFT_CONSTANTS   3  3
+#define MSPEL_MODES_31_ADDSHIFT_CONSTANTS   MSPEL_MODES_13_ADDSHIFT_CONSTANTS
+#define MSPEL_MODES_32_ADDSHIFT_CONSTANTS   MSPEL_MODES_23_ADDSHIFT_CONSTANTS
+#define MSPEL_MODES_33_ADDSHIFT_CONSTANTS   15 5
+
+@ The addition and shift constants from vc1_mspel_filter.
+#define MSPEL_MODE_1_ADDSHIFT_CONSTANTS     32 6
+#define MSPEL_MODE_2_ADDSHIFT_CONSTANTS     8  4
+#define MSPEL_MODE_3_ADDSHIFT_CONSTANTS     32 6
+
+@ Setup constants in registers for a subsequent use of mspel_filter{,.16}.
+.macro mspel_constants typesize reg_a reg_b reg_c reg_d filter_a filter_b filter_c filter_d reg_add filter_add_register
+  @ Define double-word register aliases. Typesize should be i8 or i16.
+  ra .dn \reg_a\().\typesize
+  rb .dn \reg_b\().\typesize
+  rc .dn \reg_c\().\typesize
+  rd .dn \reg_d\().\typesize
+
+  @ Only set the register if the value is not 1 and unique
+  .if \filter_a != 1
+        vmov            ra,  #\filter_a              @ ra = filter_a
+  .endif
+        vmov            rb,  #\filter_b              @ rb = filter_b
+  .if \filter_b != \filter_c
+        vmov            rc,  #\filter_c              @ rc = filter_c
+  .endif
+  .if \filter_d != 1
+        vmov            rd,  #\filter_d              @ rd = filter_d
+  .endif
+  @ vdup to double the size of typesize
+  .ifc \typesize,i8
+        vdup.16         \reg_add,  \filter_add_register     @ reg_add = filter_add_register
+  .else
+        vdup.32         \reg_add,  \filter_add_register     @ reg_add = filter_add_register
+  .endif
+
+  .unreq ra
+  .unreq rb
+  .unreq rc
+  .unreq rd
+.endm
+
+@ After mspel_constants has been used, do the filtering.
+.macro mspel_filter acc dest src0 src1 src2 src3 filter_a filter_b filter_c filter_d reg_a reg_b reg_c reg_d reg_add filter_shift narrow=1
+  .if \filter_a != 1
+        @ If filter_a != 1, then we need a move and subtract instruction
+        vmov            \acc,  \reg_add                     @ acc = reg_add
+        vmlsl.u8        \acc,  \reg_a,  \src0               @ acc -= filter_a * src[-stride]
+  .else
+        @ If filter_a is 1, then just subtract without an extra move
+        vsubw.u8        \acc,  \reg_add,  \src0             @ acc = reg_add - src[-stride]      @ since filter_a == 1
+  .endif
+        vmlal.u8        \acc,  \reg_b,  \src1               @ acc += filter_b * src[0]
+  .if \filter_b != \filter_c
+        vmlal.u8        \acc,  \reg_c,  \src2               @ acc += filter_c * src[stride]
+  .else
+        @ If filter_b is the same as filter_c, use the same reg_b register
+        vmlal.u8        \acc,  \reg_b,  \src2               @ acc += filter_c * src[stride]     @ where filter_c == filter_b
+  .endif
+  .if \filter_d != 1
+        @ If filter_d != 1, then do a multiply accumulate
+        vmlsl.u8        \acc,  \reg_d,  \src3               @ acc -= filter_d * src[stride * 2]
+  .else
+        @ If filter_d is 1, then just do a subtract
+        vsubw.u8        \acc,  \acc,    \src3               @ acc -= src[stride * 2]            @ since filter_d == 1
+  .endif
+  .if \narrow
+        vqshrun.s16     \dest, \acc,    #\filter_shift      @ dest = clip_uint8(acc >> filter_shift)
+  .else
+        vshr.s16        \dest, \acc,    #\filter_shift      @ dest = acc >> filter_shift
+  .endif
+.endm
+
+@ This is similar to mspel_filter, but the input is 16-bit instead of 8-bit and narrow=0 is not supported.
+.macro mspel_filter.16 acc0 acc1 acc0_0 acc0_1 dest src0 src1 src2 src3 src4 src5 src6 src7 filter_a filter_b filter_c filter_d reg_a reg_b reg_c reg_d reg_add filter_shift
+  .if \filter_a != 1
+        vmov            \acc0,  \reg_add
+        vmov            \acc1,  \reg_add
+        vmlsl.s16       \acc0,  \reg_a,  \src0
+        vmlsl.s16       \acc1,  \reg_a,  \src1
+  .else
+        vsubw.s16       \acc0,  \reg_add,  \src0
+        vsubw.s16       \acc1,  \reg_add,  \src1
+  .endif
+        vmlal.s16       \acc0,  \reg_b,  \src2
+        vmlal.s16       \acc1,  \reg_b,  \src3
+  .if \filter_b != \filter_c
+        vmlal.s16       \acc0,  \reg_c,  \src4
+        vmlal.s16       \acc1,  \reg_c,  \src5
+  .else
+        vmlal.s16       \acc0,  \reg_b,  \src4
+        vmlal.s16       \acc1,  \reg_b,  \src5
+  .endif
+  .if \filter_d != 1
+        vmlsl.s16       \acc0,  \reg_d,  \src6
+        vmlsl.s16       \acc1,  \reg_d,  \src7
+  .else
+        vsubw.s16       \acc0,  \acc0,   \src6
+        vsubw.s16       \acc1,  \acc1,   \src7
+  .endif
+        @ Use acc0_0 and acc0_1 as temp space
+        vqshrun.s32     \acc0_0, \acc0,  #\filter_shift     @ Shift and narrow with saturation from s32 to u16
+        vqshrun.s32     \acc0_1, \acc1,  #\filter_shift
+        vqmovn.u16      \dest,  \acc0                       @ Narrow with saturation from u16 to u8
+.endm
+
+@ Register usage for put_vc1_mspel_mc functions. Registers marked 'hv' are only used in put_vc1_mspel_mc_hv.
+@
+@   r0        adjusted dst
+@   r1        adjusted src
+@   r2        stride
+@   r3        adjusted rnd
+@   r4 [hv]   tmp
+@   r11 [hv]  sp saved
+@   r12       loop counter
+@   d0        src[-stride]
+@   d1        src[0]
+@   d2        src[stride]
+@   d3        src[stride * 2]
+@   q0 [hv]   src[-stride]
+@   q1 [hv]   src[0]
+@   q2 [hv]   src[stride]
+@   q3 [hv]   src[stride * 2]
+@   d21       often result from mspel_filter
+@   q11       accumulator 0
+@   q12 [hv]  accumulator 1
+@   q13       accumulator initial value
+@   d28       filter_a
+@   d29       filter_b
+@   d30       filter_c
+@   d31       filter_d
+
+@ (uint8_t *dst [r0], const uint8_t *src [r1], ptrdiff_t stride [r2], int rnd [r3])
+.macro put_vc1_mspel_mc_hv hmode vmode filter_h_a filter_h_b filter_h_c filter_h_d filter_v_a filter_v_b filter_v_c filter_v_d filter_add filter_shift
+function ff_put_vc1_mspel_mc\hmode\()\vmode\()_neon, export=1
+        push            {r4, r11, lr}
+        mov             r11, sp                 @ r11 = stack pointer before realignmnet
+A       bic             sp,  sp,  #15           @ sp = round down to multiple of 16 bytes
+T       bic             r4,  r11, #15
+T       mov             sp,  r4
+        sub             sp,  sp,  #(8*2*16)     @ make space for 8 rows * 2 byte per element * 16 elements per row (to fit 11 actual elements per row)
+        mov             r4,  sp                 @ r4 = int16_t tmp[8 * 16]
+
+        sub             r1,  r1,  #1            @ src -= 1
+  .if \filter_add != 0
+        add             r3,  r3,  #\filter_add  @ r3 = filter_add + rnd
+  .endif
+        mov             r12, #8                 @ loop counter
+        sub             r1,  r1,  r2            @ r1 = &src[-stride]      @ slide back
+
+        @ Do vertical filtering from src into tmp
+        mspel_constants i8 d28 d29 d30 d31 \filter_v_a \filter_v_b \filter_v_c \filter_v_d q13 r3
+
+        vld1.64         {d0,d1}, [r1], r2
+        vld1.64         {d2,d3}, [r1], r2
+        vld1.64         {d4,d5}, [r1], r2
+
+1:
+        subs            r12,  r12,  #4
+
+        vld1.64         {d6,d7}, [r1], r2
+        mspel_filter    q11 q11 d0 d2 d4 d6 \filter_v_a \filter_v_b \filter_v_c \filter_v_d d28 d29 d30 d31 q13 \filter_shift narrow=0
+        mspel_filter    q12 q12 d1 d3 d5 d7 \filter_v_a \filter_v_b \filter_v_c \filter_v_d d28 d29 d30 d31 q13 \filter_shift narrow=0
+        vst1.64         {q11,q12}, [r4,:128]!   @ store and increment
+
+        vld1.64         {d0,d1}, [r1], r2
+        mspel_filter    q11 q11 d2 d4 d6 d0 \filter_v_a \filter_v_b \filter_v_c \filter_v_d d28 d29 d30 d31 q13 \filter_shift narrow=0
+        mspel_filter    q12 q12 d3 d5 d7 d1 \filter_v_a \filter_v_b \filter_v_c \filter_v_d d28 d29 d30 d31 q13 \filter_shift narrow=0
+        vst1.64         {q11,q12}, [r4,:128]!   @ store and increment
+
+        vld1.64         {d2,d3}, [r1], r2
+        mspel_filter    q11 q11 d4 d6 d0 d2 \filter_v_a \filter_v_b \filter_v_c \filter_v_d d28 d29 d30 d31 q13 \filter_shift narrow=0
+        mspel_filter    q12 q12 d5 d7 d1 d3 \filter_v_a \filter_v_b \filter_v_c \filter_v_d d28 d29 d30 d31 q13 \filter_shift narrow=0
+        vst1.64         {q11,q12}, [r4,:128]!   @ store and increment
+
+        vld1.64         {d4,d5}, [r1], r2
+        mspel_filter    q11 q11 d6 d0 d2 d4 \filter_v_a \filter_v_b \filter_v_c \filter_v_d d28 d29 d30 d31 q13 \filter_shift narrow=0
+        mspel_filter    q12 q12 d7 d1 d3 d5 \filter_v_a \filter_v_b \filter_v_c \filter_v_d d28 d29 d30 d31 q13 \filter_shift narrow=0
+        vst1.64         {q11,q12}, [r4,:128]!   @ store and increment
+
+        bne             1b
+
+        rsb             r3,   r3,  #(64 + \filter_add)      @ r3 = (64 + filter_add) - r3
+        mov             r12,  #8                @ loop counter
+        mov             r4,   sp                @ r4 = tmp
+
+        @ Do horizontal filtering from temp to dst
+        mspel_constants i16 d28 d29 d30 d31 \filter_h_a \filter_h_b \filter_h_c \filter_h_d q13 r3
+
+2:
+        subs            r12,  r12,  #1
+
+        vld1.64         {q0,q1}, [r4,:128]!     @ read one line of tmp
+        vext.16         q2,   q0,   q1,  #2
+        vext.16         q3,   q0,   q1,  #3
+        vext.16         q1,   q0,   q1,  #1     @ do last because it writes to q1 which is read by the other vext instructions
+
+        mspel_filter.16 q11 q12 d22 d23 d21 d0 d1 d2 d3 d4 d5 d6 d7 \filter_h_a \filter_h_b \filter_h_c \filter_h_d d28 d29 d30 d31 q13 7
+
+        vst1.64         {d21}, [r0,:64], r2     @ store and increment dst
+
+        bne             2b
+
+        mov             sp,  r11
+        pop             {r4, r11, pc}
+endfunc
+.endm
+
+@ Use C preprocessor and assembler macros to expand to functions for horizontal and vertical filtering.
+#define PUT_VC1_MSPEL_MC_HV(hmode, vmode)   \
+    put_vc1_mspel_mc_hv hmode vmode \
+        MSPEL_MODE_ ## hmode ## _MUL_CONSTANTS \
+        MSPEL_MODE_ ## vmode ## _MUL_CONSTANTS \
+        MSPEL_MODES_ ## hmode ## vmode ## _ADDSHIFT_CONSTANTS
+
+PUT_VC1_MSPEL_MC_HV(1, 1)
+PUT_VC1_MSPEL_MC_HV(1, 2)
+PUT_VC1_MSPEL_MC_HV(1, 3)
+PUT_VC1_MSPEL_MC_HV(2, 1)
+PUT_VC1_MSPEL_MC_HV(2, 2)
+PUT_VC1_MSPEL_MC_HV(2, 3)
+PUT_VC1_MSPEL_MC_HV(3, 1)
+PUT_VC1_MSPEL_MC_HV(3, 2)
+PUT_VC1_MSPEL_MC_HV(3, 3)
+
+#undef PUT_VC1_MSPEL_MC_HV
+
+.macro  put_vc1_mspel_mc_h_only hmode filter_a filter_b filter_c filter_d filter_add filter_shift
+function ff_put_vc1_mspel_mc\hmode\()0_neon, export=1
+        rsb             r3,   r3,   #\filter_add        @ r3 = filter_add - r = filter_add - rnd
+        mov             r12,  #8                        @ loop counter
+        sub             r1,   r1,   #1                  @ slide back, using immediate
+
+        mspel_constants i8 d28 d29 d30 d31 \filter_a \filter_b \filter_c \filter_d q13 r3
+
+1:
+        subs            r12,  r12,  #1
+
+        vld1.64         {d0,d1}, [r1], r2               @ read 16 bytes even though we only need 11, also src += stride
+        vext.8          d2,   d0,   d1,  #2
+        vext.8          d3,   d0,   d1,  #3
+        vext.8          d1,   d0,   d1,  #1             @ do last because it writes to d1 which is read by the other vext instructions
+
+        mspel_filter    q11 d21 d0 d1 d2 d3 \filter_a \filter_b \filter_c \filter_d d28 d29 d30 d31 q13 \filter_shift
+
+        vst1.64         {d21}, [r0,:64], r2             @ store and increment dst
+
+        bne             1b
+
+        bx              lr
+endfunc
+.endm
+
+@ Use C preprocessor and assembler macros to expand to functions for horizontal only filtering.
+#define PUT_VC1_MSPEL_MC_H_ONLY(hmode) \
+        put_vc1_mspel_mc_h_only hmode MSPEL_MODE_ ## hmode ## _MUL_CONSTANTS MSPEL_MODE_ ## hmode ## _ADDSHIFT_CONSTANTS
+
+PUT_VC1_MSPEL_MC_H_ONLY(1)
+PUT_VC1_MSPEL_MC_H_ONLY(2)
+PUT_VC1_MSPEL_MC_H_ONLY(3)
+
+#undef PUT_VC1_MSPEL_MC_H_ONLY
+
+@ (uint8_t *dst [r0], const uint8_t *src [r1], ptrdiff_t stride [r2], int rnd [r3])
+.macro put_vc1_mspel_mc_v_only vmode filter_a filter_b filter_c filter_d filter_add filter_shift
+function ff_put_vc1_mspel_mc0\vmode\()_neon, export=1
+        add             r3,   r3,   #\filter_add - 1    @ r3 = filter_add - r = filter_add - (1 - rnd) = filter_add - 1 + rnd
+        mov             r12,  #8                        @ loop counter
+        sub             r1,   r1,   r2                  @ r1 = &src[-stride]      @ slide back
+
+        mspel_constants i8 d28 d29 d30 d31 \filter_a \filter_b \filter_c \filter_d q13 r3
+
+        vld1.64         {d0},  [r1], r2                 @ d0 = src[-stride]
+        vld1.64         {d1},  [r1], r2                 @ d1 = src[0]
+        vld1.64         {d2},  [r1], r2                 @ d2 = src[stride]
+
+1:
+        subs            r12,  r12,  #4
+
+        vld1.64         {d3},  [r1], r2                 @ d3 = src[stride * 2]
+        mspel_filter    q11 d21 d0 d1 d2 d3 \filter_a \filter_b \filter_c \filter_d d28 d29 d30 d31 q13 \filter_shift
+        vst1.64         {d21}, [r0,:64], r2             @ store and increment dst
+
+        vld1.64         {d0},  [r1], r2                 @ d0 = next line
+        mspel_filter    q11 d21 d1 d2 d3 d0 \filter_a \filter_b \filter_c \filter_d d28 d29 d30 d31 q13 \filter_shift
+        vst1.64         {d21}, [r0,:64], r2             @ store and increment dst
+
+        vld1.64         {d1},  [r1], r2                 @ d1 = next line
+        mspel_filter    q11 d21 d2 d3 d0 d1 \filter_a \filter_b \filter_c \filter_d d28 d29 d30 d31 q13 \filter_shift
+        vst1.64         {d21}, [r0,:64], r2             @ store and increment dst
+
+        vld1.64         {d2},  [r1], r2                 @ d2 = next line
+        mspel_filter    q11 d21 d3 d0 d1 d2 \filter_a \filter_b \filter_c \filter_d d28 d29 d30 d31 q13 \filter_shift
+        vst1.64         {d21}, [r0,:64], r2             @ store and increment dst
+
+        bne             1b
+
+        bx              lr
+endfunc
+.endm
+
+@ Use C preprocessor and assembler macros to expand to functions for vertical only filtering.
+#define PUT_VC1_MSPEL_MC_V_ONLY(vmode) \
+        put_vc1_mspel_mc_v_only vmode MSPEL_MODE_ ## vmode ## _MUL_CONSTANTS MSPEL_MODE_ ## vmode ## _ADDSHIFT_CONSTANTS
+
+PUT_VC1_MSPEL_MC_V_ONLY(1)
+PUT_VC1_MSPEL_MC_V_ONLY(2)
+PUT_VC1_MSPEL_MC_V_ONLY(3)
+
+#undef PUT_VC1_MSPEL_MC_V_ONLY
+
+function ff_put_pixels8x8_neon, export=1
+        vld1.64         {d0}, [r1], r2
+        vld1.64         {d1}, [r1], r2
+        vld1.64         {d2}, [r1], r2
+        vld1.64         {d3}, [r1], r2
+        vld1.64         {d4}, [r1], r2
+        vld1.64         {d5}, [r1], r2
+        vld1.64         {d6}, [r1], r2
+        vld1.64         {d7}, [r1]
+        vst1.64         {d0}, [r0,:64], r2
+        vst1.64         {d1}, [r0,:64], r2
+        vst1.64         {d2}, [r0,:64], r2
+        vst1.64         {d3}, [r0,:64], r2
+        vst1.64         {d4}, [r0,:64], r2
+        vst1.64         {d5}, [r0,:64], r2
+        vst1.64         {d6}, [r0,:64], r2
+        vst1.64         {d7}, [r0,:64]
+        bx              lr
+endfunc
+
+function ff_vc1_inv_trans_8x8_dc_neon, export=1
+        ldrsh           r2, [r2]              @ int dc = block[0];
+
+        vld1.64         {d0},  [r0,:64], r1
+        vld1.64         {d1},  [r0,:64], r1
+        vld1.64         {d4},  [r0,:64], r1
+        vld1.64         {d5},  [r0,:64], r1
+
+        add             r2, r2, r2, lsl #1    @ dc = (3 * dc +  1) >> 1;
+        vld1.64         {d6},  [r0,:64], r1
+        add             r2, r2, #1
+        vld1.64         {d7},  [r0,:64], r1
+        vld1.64         {d16}, [r0,:64], r1
+        vld1.64         {d17}, [r0,:64], r1
+        asr             r2, r2, #1
+
+        sub             r0,  r0,  r1, lsl #3  @ restore r0 to original value
+
+        add             r2, r2, r2, lsl #1    @ dc = (3 * dc + 16) >> 5;
+        add             r2, r2, #16
+        asr             r2, r2, #5
+
+        vdup.16         q1,  r2               @ dc
+
+        vaddw.u8        q9,   q1,  d0
+        vaddw.u8        q10,  q1,  d1
+        vaddw.u8        q11,  q1,  d4
+        vaddw.u8        q12,  q1,  d5
+        vqmovun.s16     d0,  q9
+        vqmovun.s16     d1,  q10
+        vqmovun.s16     d4,  q11
+        vst1.64         {d0},  [r0,:64], r1
+        vqmovun.s16     d5,  q12
+        vst1.64         {d1},  [r0,:64], r1
+        vaddw.u8        q13,  q1,  d6
+        vst1.64         {d4},  [r0,:64], r1
+        vaddw.u8        q14,  q1,  d7
+        vst1.64         {d5},  [r0,:64], r1
+        vaddw.u8        q15,  q1,  d16
+        vaddw.u8        q1,   q1,  d17        @ this destroys q1
+        vqmovun.s16     d6,  q13
+        vqmovun.s16     d7,  q14
+        vqmovun.s16     d16, q15
+        vqmovun.s16     d17, q1
+        vst1.64         {d6},  [r0,:64], r1
+        vst1.64         {d7},  [r0,:64], r1
+        vst1.64         {d16}, [r0,:64], r1
+        vst1.64         {d17}, [r0,:64]
+        bx              lr
+endfunc
+
+function ff_vc1_inv_trans_8x4_dc_neon, export=1
+        ldrsh           r2, [r2]              @ int dc = block[0];
+
+        vld1.64         {d0},  [r0,:64], r1
+        vld1.64         {d1},  [r0,:64], r1
+        vld1.64         {d4},  [r0,:64], r1
+        vld1.64         {d5},  [r0,:64], r1
+
+        add             r2, r2, r2, lsl #1    @ dc = ( 3 * dc +  1) >> 1;
+
+        sub             r0,  r0,  r1, lsl #2  @ restore r0 to original value
+
+        add             r2, r2, #1
+        asr             r2, r2, #1
+
+        add             r2, r2, r2, lsl #4    @ dc = (17 * dc + 64) >> 7;
+        add             r2, r2, #64
+        asr             r2, r2, #7
+
+        vdup.16         q1,  r2               @ dc
+
+        vaddw.u8        q3,  q1,  d0
+        vaddw.u8        q8,  q1,  d1
+        vaddw.u8        q9,  q1,  d4
+        vaddw.u8        q10, q1,  d5
+        vqmovun.s16     d0,  q3
+        vqmovun.s16     d1,  q8
+        vqmovun.s16     d4,  q9
+        vst1.64         {d0},  [r0,:64], r1
+        vqmovun.s16     d5,  q10
+        vst1.64         {d1},  [r0,:64], r1
+        vst1.64         {d4},  [r0,:64], r1
+        vst1.64         {d5},  [r0,:64]
+        bx              lr
+endfunc
+
+function ff_vc1_inv_trans_4x8_dc_neon, export=1
+        ldrsh           r2, [r2]              @ int dc = block[0];
+
+        vld1.32         {d0[]},   [r0,:32], r1
+        vld1.32         {d1[]},   [r0,:32], r1
+        vld1.32         {d0[1]},  [r0,:32], r1
+        vld1.32         {d1[1]},  [r0,:32], r1
+
+        add             r2, r2, r2, lsl #4    @ dc = (17 * dc +  4) >> 3;
+        vld1.32         {d4[]},   [r0,:32], r1
+        add             r2, r2, #4
+        vld1.32         {d5[]},   [r0,:32], r1
+        vld1.32         {d4[1]},  [r0,:32], r1
+        asr             r2, r2, #3
+        vld1.32         {d5[1]},  [r0,:32], r1
+
+        add             r2, r2, r2, lsl #1    @ dc = (12 * dc + 64) >> 7;
+
+        sub             r0,  r0,  r1, lsl #3  @ restore r0 to original value
+
+        lsl             r2, r2, #2
+        add             r2, r2, #64
+        asr             r2, r2, #7
+
+        vdup.16         q1,  r2               @ dc
+
+        vaddw.u8        q3,  q1,  d0
+        vaddw.u8        q8,  q1,  d1
+        vaddw.u8        q9,  q1,  d4
+        vaddw.u8        q10, q1,  d5
+        vqmovun.s16     d0,  q3
+        vst1.32         {d0[0]},  [r0,:32], r1
+        vqmovun.s16     d1,  q8
+        vst1.32         {d1[0]},  [r0,:32], r1
+        vqmovun.s16     d4,  q9
+        vst1.32         {d0[1]},  [r0,:32], r1
+        vqmovun.s16     d5,  q10
+        vst1.32         {d1[1]},  [r0,:32], r1
+        vst1.32         {d4[0]},  [r0,:32], r1
+        vst1.32         {d5[0]},  [r0,:32], r1
+        vst1.32         {d4[1]},  [r0,:32], r1
+        vst1.32         {d5[1]},  [r0,:32]
+        bx              lr
+endfunc
+
+function ff_vc1_inv_trans_4x4_dc_neon, export=1
+        ldrsh           r2, [r2]              @ int dc = block[0];
+
+        vld1.32         {d0[]},   [r0,:32], r1
+        vld1.32         {d1[]},   [r0,:32], r1
+        vld1.32         {d0[1]},  [r0,:32], r1
+        vld1.32         {d1[1]},  [r0,:32], r1
+
+        add             r2, r2, r2, lsl #4    @ dc = (17 * dc +  4) >> 3;
+
+        sub             r0,  r0,  r1, lsl #2  @ restore r0 to original value
+
+        add             r2, r2, #4
+        asr             r2, r2, #3
+
+        add             r2, r2, r2, lsl #4    @ dc = (17 * dc + 64) >> 7;
+        add             r2, r2, #64
+        asr             r2, r2, #7
+
+        vdup.16         q1,  r2               @ dc
+
+        vaddw.u8        q2,  q1,  d0
+        vaddw.u8        q3,  q1,  d1
+        vqmovun.s16     d0,  q2
+        vst1.32         {d0[0]},  [r0,:32], r1
+        vqmovun.s16     d1,  q3
+        vst1.32         {d1[0]},  [r0,:32], r1
+        vst1.32         {d0[1]},  [r0,:32], r1
+        vst1.32         {d1[1]},  [r0,:32]
+        bx              lr
+endfunc
diff --git a/libavcodec/vc1dsp.c b/libavcodec/vc1dsp.c
index 12295fff2b..7ef580d24e 100644
--- a/libavcodec/vc1dsp.c
+++ b/libavcodec/vc1dsp.c
@@ -854,6 +854,8 @@ av_cold void ff_vc1dsp_init(VC1DSPContext* dsp) {
     dsp->sprite_v_double_twoscale = sprite_v_double_twoscale_c;
 #endif
 
+    if (ARCH_ARM)
+        ff_vc1dsp_init_arm(dsp);
     if (ARCH_PPC)
         ff_vc1dsp_init_ppc(dsp);
     if (ARCH_X86)
diff --git a/libavcodec/vc1dsp.h b/libavcodec/vc1dsp.h
index 84d4b707a8..862119264b 100644
--- a/libavcodec/vc1dsp.h
+++ b/libavcodec/vc1dsp.h
@@ -75,6 +75,7 @@ typedef struct VC1DSPContext {
 } VC1DSPContext;
 
 void ff_vc1dsp_init(VC1DSPContext* c);
+void ff_vc1dsp_init_arm(VC1DSPContext* dsp);
 void ff_vc1dsp_init_ppc(VC1DSPContext *c);
 void ff_vc1dsp_init_x86(VC1DSPContext* dsp);