1 // Copyright 2018 Google Inc. All Rights Reserved.
2 //
3 // Use of this source code is governed by a BSD-style license
4 // that can be found in the COPYING file in the root of the source
5 // tree. An additional intellectual property rights grant can be found
6 // in the file PATENTS. All contributing project authors may
7 // be found in the AUTHORS file in the root of the source tree.
8 // -----------------------------------------------------------------------------
9
10 #ifndef WEBP_DSP_QUANT_H_
11 #define WEBP_DSP_QUANT_H_
12
13 #include <string.h>
14
15 #include "src/dsp/dsp.h"
16 #include "src/webp/types.h"
17
18 #if defined(WEBP_USE_NEON) && !defined(WEBP_ANDROID_NEON) && \
19 !defined(WEBP_HAVE_NEON_RTCD)
20 #include <arm_neon.h>
21
22 #define IsFlat IsFlat_NEON
23
horizontal_add_uint32x4(const uint32x4_t a)24 static uint32x2_t horizontal_add_uint32x4(const uint32x4_t a) {
25 const uint64x2_t b = vpaddlq_u32(a);
26 return vadd_u32(vreinterpret_u32_u64(vget_low_u64(b)),
27 vreinterpret_u32_u64(vget_high_u64(b)));
28 }
29
IsFlat(const int16_t * levels,int num_blocks,int thresh)30 static WEBP_INLINE int IsFlat(const int16_t* levels, int num_blocks,
31 int thresh) {
32 const int16x8_t tst_ones = vdupq_n_s16(-1);
33 uint32x4_t sum = vdupq_n_u32(0);
34
35 for (int i = 0; i < num_blocks; ++i) {
36 // Set DC to zero.
37 const int16x8_t a_0 = vsetq_lane_s16(0, vld1q_s16(levels), 0);
38 const int16x8_t a_1 = vld1q_s16(levels + 8);
39
40 const uint16x8_t b_0 = vshrq_n_u16(vtstq_s16(a_0, tst_ones), 15);
41 const uint16x8_t b_1 = vshrq_n_u16(vtstq_s16(a_1, tst_ones), 15);
42
43 sum = vpadalq_u16(sum, b_0);
44 sum = vpadalq_u16(sum, b_1);
45
46 levels += 16;
47 }
48 return thresh >= (int32_t)vget_lane_u32(horizontal_add_uint32x4(sum), 0);
49 }
50
51 #else
52
53 #define IsFlat IsFlat_C
54
IsFlat(const int16_t * levels,int num_blocks,int thresh)55 static WEBP_INLINE int IsFlat(const int16_t* levels, int num_blocks,
56 int thresh) {
57 int score = 0;
58 while (num_blocks-- > 0) { // TODO(skal): refine positional scoring?
59 int i;
60 for (i = 1; i < 16; ++i) { // omit DC, we're only interested in AC
61 score += (levels[i] != 0);
62 if (score > thresh) return 0;
63 }
64 levels += 16;
65 }
66 return 1;
67 }
68
69 #endif // defined(WEBP_USE_NEON) && !defined(WEBP_ANDROID_NEON) &&
70 // !defined(WEBP_HAVE_NEON_RTCD)
71
IsFlatSource16(const uint8_t * src)72 static WEBP_INLINE int IsFlatSource16(const uint8_t* src) {
73 const uint32_t v = src[0] * 0x01010101u;
74 int i;
75 for (i = 0; i < 16; ++i) {
76 if (memcmp(src + 0, &v, 4) || memcmp(src + 4, &v, 4) ||
77 memcmp(src + 8, &v, 4) || memcmp(src + 12, &v, 4)) {
78 return 0;
79 }
80 src += BPS;
81 }
82 return 1;
83 }
84
85 #endif // WEBP_DSP_QUANT_H_
86