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 "src/dsp/dsp.h"
14 #include "src/webp/types.h"
15
16 #if defined(WEBP_USE_NEON) && !defined(WEBP_ANDROID_NEON) && \
17 !defined(WEBP_HAVE_NEON_RTCD)
18 #include <arm_neon.h>
19
20 #define IsFlat IsFlat_NEON
21
horizontal_add_uint32x4(const uint32x4_t a)22 static uint32x2_t horizontal_add_uint32x4(const uint32x4_t a) {
23 const uint64x2_t b = vpaddlq_u32(a);
24 return vadd_u32(vreinterpret_u32_u64(vget_low_u64(b)),
25 vreinterpret_u32_u64(vget_high_u64(b)));
26 }
27
IsFlat(const int16_t * levels,int num_blocks,int thresh)28 static WEBP_INLINE int IsFlat(const int16_t* levels, int num_blocks,
29 int thresh) {
30 const int16x8_t tst_ones = vdupq_n_s16(-1);
31 uint32x4_t sum = vdupq_n_u32(0);
32
33 for (int i = 0; i < num_blocks; ++i) {
34 // Set DC to zero.
35 const int16x8_t a_0 = vsetq_lane_s16(0, vld1q_s16(levels), 0);
36 const int16x8_t a_1 = vld1q_s16(levels + 8);
37
38 const uint16x8_t b_0 = vshrq_n_u16(vtstq_s16(a_0, tst_ones), 15);
39 const uint16x8_t b_1 = vshrq_n_u16(vtstq_s16(a_1, tst_ones), 15);
40
41 sum = vpadalq_u16(sum, b_0);
42 sum = vpadalq_u16(sum, b_1);
43
44 levels += 16;
45 }
46 return thresh >= (int32_t)vget_lane_u32(horizontal_add_uint32x4(sum), 0);
47 }
48
49 #else
50
51 #define IsFlat IsFlat_C
52
IsFlat(const int16_t * levels,int num_blocks,int thresh)53 static WEBP_INLINE int IsFlat(const int16_t* levels, int num_blocks,
54 int thresh) {
55 int score = 0;
56 while (num_blocks-- > 0) { // TODO(skal): refine positional scoring?
57 int i;
58 for (i = 1; i < 16; ++i) { // omit DC, we're only interested in AC
59 score += (levels[i] != 0);
60 if (score > thresh) return 0;
61 }
62 levels += 16;
63 }
64 return 1;
65 }
66
67 #endif // defined(WEBP_USE_NEON) && !defined(WEBP_ANDROID_NEON) &&
68 // !defined(WEBP_HAVE_NEON_RTCD)
69
70 #endif // WEBP_DSP_QUANT_H_
71