1 /*
2 * Copyright 2020 The libgav1 Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #ifndef LIBGAV1_SRC_DSP_FILM_GRAIN_COMMON_H_
18 #define LIBGAV1_SRC_DSP_FILM_GRAIN_COMMON_H_
19
20 #include <cstddef>
21 #include <cstdint>
22 #include <memory>
23 #include <type_traits>
24
25 #include "src/dsp/common.h"
26 #include "src/utils/array_2d.h"
27 #include "src/utils/constants.h"
28 #include "src/utils/cpu.h"
29
30 namespace libgav1 {
31
32 template <int bitdepth>
GetGrainMax()33 int GetGrainMax() {
34 return (1 << (bitdepth - 1)) - 1;
35 }
36
37 template <int bitdepth>
GetGrainMin()38 int GetGrainMin() {
39 return -(1 << (bitdepth - 1));
40 }
41
GetFilmGrainRandomNumber(int bits,uint16_t * seed)42 inline int GetFilmGrainRandomNumber(int bits, uint16_t* seed) {
43 uint16_t s = *seed;
44 uint16_t bit = (s ^ (s >> 1) ^ (s >> 3) ^ (s >> 12)) & 1;
45 s = (s >> 1) | (bit << 15);
46 *seed = s;
47 return s >> (16 - bits);
48 }
49
50 enum {
51 kAutoRegressionBorder = 3,
52 // The width of the luma noise array.
53 kLumaWidth = 82,
54 // The height of the luma noise array.
55 kLumaHeight = 73,
56 // The two possible widths of the chroma noise array.
57 kMinChromaWidth = 44,
58 kMaxChromaWidth = 82,
59 // The two possible heights of the chroma noise array.
60 kMinChromaHeight = 38,
61 kMaxChromaHeight = 73,
62 // The scaling lookup table maps bytes to bytes, so only uses 256 elements,
63 // plus one for overflow in 10bit lookups.
64 kScalingLookupTableSize = 257,
65 // Padding is added to the scaling lookup table to permit overwrites by
66 // InitializeScalingLookupTable_NEON.
67 kScalingLookupTablePadding = 6,
68 // Padding is added to each row of the noise image to permit overreads by
69 // BlendNoiseWithImageLuma_NEON and overwrites by WriteOverlapLine8bpp_NEON.
70 kNoiseImagePadding = 7,
71 // Padding is added to the end of the |noise_stripes_| buffer to permit
72 // overreads by WriteOverlapLine8bpp_NEON.
73 kNoiseStripePadding = 7,
74 }; // anonymous enum
75
76 } // namespace libgav1
77
78 #endif // LIBGAV1_SRC_DSP_FILM_GRAIN_COMMON_H_
79