From 042e70e45e74ad5105d1c9f35375350000b56b39 Mon Sep 17 00:00:00 2001
From: Yaowu Xu <yaowu@google.com>
Date: Thu, 30 May 2013 14:24:12 -0700
Subject: [PATCH] Changed to use a new variant of WHT
The commit changed to use a new variant of Walsh-Hadamard Transform
by Tim Terriberry. This new variant has the best compression among a
number of variants that developed by Tim.
Change-Id: Icb3a88515463cfc644b17ca046fcd139db2557e9
---
vp9/common/vp9_idct.c | 42 +++++++++++++++++++-----------------------
vp9/common/vp9_idct.h | 1 +
vp9/encoder/vp9_dct.c | 30 ++++++++++++++----------------
3 files changed, 34 insertions(+), 39 deletions(-)
diff --git a/vp9/common/vp9_idct.c b/vp9/common/vp9_idct.c
index 026ba913df..dcc7f03307 100644
--- a/vp9/common/vp9_idct.c
+++ b/vp9/common/vp9_idct.c
@@ -32,20 +32,17 @@ void vp9_short_iwalsh4x4_add_c(int16_t *input, uint8_t *dest, int dest_stride) {
c1 = ip[1] >> WHT_UPSCALE_FACTOR;
d1 = ip[2] >> WHT_UPSCALE_FACTOR;
b1 = ip[3] >> WHT_UPSCALE_FACTOR;
-
- c1 = a1 - c1;
- b1 += d1;
- e1 = (c1 - b1) >> 1;
- a1 -= e1;
- d1 += e1;
- b1 = a1 - b1;
- c1 -= d1;
-
+ a1 += c1;
+ d1 -= b1;
+ e1 = (a1 - d1) >> 1;
+ b1 = e1 - b1;
+ c1 = e1 - c1;
+ a1 -= b1;
+ d1 += c1;
op[0] = a1;
op[1] = b1;
op[2] = c1;
op[3] = d1;
-
ip += 4;
op += 4;
}
@@ -56,15 +53,13 @@ void vp9_short_iwalsh4x4_add_c(int16_t *input, uint8_t *dest, int dest_stride) {
c1 = ip[4 * 1];
d1 = ip[4 * 2];
b1 = ip[4 * 3];
-
- c1 = a1 - c1;
- b1 += d1;
- e1 = (c1 - b1) >> 1;
- a1 -= e1;
- d1 += e1;
- b1 = a1 - b1;
- c1 -= d1;
-
+ a1 += c1;
+ d1 -= b1;
+ e1 = (a1 - d1) >> 1;
+ b1 = e1 - b1;
+ c1 = e1 - c1;
+ a1 -= b1;
+ d1 += c1;
dest[dest_stride * 0] = clip_pixel(dest[dest_stride * 0] + a1);
dest[dest_stride * 1] = clip_pixel(dest[dest_stride * 1] + b1);
dest[dest_stride * 2] = clip_pixel(dest[dest_stride * 2] + c1);
@@ -84,16 +79,17 @@ void vp9_short_iwalsh4x4_1_add_c(int16_t *in, uint8_t *dest, int dest_stride) {
a1 = ip[0] >> WHT_UPSCALE_FACTOR;
e1 = a1 >> 1;
- op[0] = op[1] = op[2] = a1 - e1;
- op[3] = e1;
+ a1 -= e1;
+ op[0] = a1;
+ op[1] = op[2] = op[3] = e1;
ip = tmp;
for (i = 0; i < 4; i++) {
e1 = ip[0] >> 1;
a1 = ip[0] - e1;
dest[dest_stride * 0] = clip_pixel(dest[dest_stride * 0] + a1);
- dest[dest_stride * 1] = clip_pixel(dest[dest_stride * 1] + a1);
- dest[dest_stride * 2] = clip_pixel(dest[dest_stride * 2] + a1);
+ dest[dest_stride * 1] = clip_pixel(dest[dest_stride * 1] + e1);
+ dest[dest_stride * 2] = clip_pixel(dest[dest_stride * 2] + e1);
dest[dest_stride * 3] = clip_pixel(dest[dest_stride * 3] + e1);
ip++;
dest++;
diff --git a/vp9/common/vp9_idct.h b/vp9/common/vp9_idct.h
index 176bf5da43..af35432c44 100644
--- a/vp9/common/vp9_idct.h
+++ b/vp9/common/vp9_idct.h
@@ -17,6 +17,7 @@
#include "vpx/vpx_integer.h"
#include "vp9/common/vp9_common.h"
+
// Constants and Macros used by all idct/dct functions
#define DCT_CONST_BITS 14
#define DCT_CONST_ROUNDING (1 << (DCT_CONST_BITS - 1))
diff --git a/vp9/encoder/vp9_dct.c b/vp9/encoder/vp9_dct.c
index d22644424e..8d4eec1394 100644
--- a/vp9/encoder/vp9_dct.c
+++ b/vp9/encoder/vp9_dct.c
@@ -606,14 +606,13 @@ void vp9_short_walsh4x4_c(short *input, short *output, int pitch) {
c1 = ip[2 * pitch_short];
d1 = ip[3 * pitch_short];
- b1 = a1 - b1;
- c1 += d1;
- e1 = (c1 - b1) >> 1;
- a1 += e1;
- d1 -= e1;
- c1 = a1 - c1;
- b1 -= d1;
-
+ a1 += b1;
+ d1 = d1 - c1;
+ e1 = (a1 - d1) >> 1;
+ b1 = e1 - b1;
+ c1 = e1 - c1;
+ a1 -= c1;
+ d1 += b1;
op[0] = a1;
op[4] = c1;
op[8] = d1;
@@ -631,14 +630,13 @@ void vp9_short_walsh4x4_c(short *input, short *output, int pitch) {
c1 = ip[2];
d1 = ip[3];
- b1 = a1 - b1;
- c1 += d1;
- e1 = (c1 - b1) >> 1;
- a1 += e1;
- d1 -= e1;
- c1 = a1 - c1;
- b1 -= d1;
-
+ a1 += b1;
+ d1 -= c1;
+ e1 = (a1 - d1) >> 1;
+ b1 = e1 - b1;
+ c1 = e1 - c1;
+ a1 -= c1;
+ d1 += b1;
op[0] = a1 << WHT_UPSCALE_FACTOR;
op[1] = c1 << WHT_UPSCALE_FACTOR;
op[2] = d1 << WHT_UPSCALE_FACTOR;
--
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