1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
|
/*
* Copyright 2019 The libgav1 Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef LIBGAV1_SRC_QUANTIZER_H_
#define LIBGAV1_SRC_QUANTIZER_H_
#include <cstdint>
#include "src/utils/constants.h"
#include "src/utils/dynamic_buffer.h"
#include "src/utils/segmentation.h"
#include "src/utils/types.h"
namespace libgav1 {
using QuantizerMatrix = std::array<
std::array<std::array<DynamicBuffer<uint8_t>, kNumTransformSizes>,
kNumPlaneTypes>,
kNumQuantizerLevelsForQuantizerMatrix>;
// Implements the dequantization functions of Section 7.12.2.
class Quantizer {
public:
Quantizer(int bitdepth, const QuantizerParameters* params);
// Returns the quantizer value for the dc coefficient for the given plane.
// The caller should call GetQIndex() with Tile::current_quantizer_index_ as
// the |base_qindex| argument, and pass the return value as the |qindex|
// argument to this method.
int GetDcValue(Plane plane, int qindex) const;
// Returns the quantizer value for the ac coefficient for the given plane.
// The caller should call GetQIndex() with Tile::current_quantizer_index_ as
// the |base_qindex| argument, and pass the return value as the |qindex|
// argument to this method.
int GetAcValue(Plane plane, int qindex) const;
private:
const QuantizerParameters& params_;
const int16_t* dc_lookup_;
const int16_t* ac_lookup_;
};
// Initialize the quantizer matrix.
bool InitializeQuantizerMatrix(QuantizerMatrix* quantizer_matrix);
// Get the quantizer index for the |index|th segment.
//
// This function has two use cases. What should be passed as the |base_qindex|
// argument depends on the use case.
// 1. While parsing the uncompressed header or transform type, pass
// Quantizer::base_index.
// Note: In this use case, the caller only cares about whether the return
// value is zero.
// 2. To generate the |qindex| argument to Quantizer::GetDcQuant() or
// Quantizer::GetAcQuant(), pass Tile::current_quantizer_index_.
int GetQIndex(const Segmentation& segmentation, int index, int base_qindex);
} // namespace libgav1
#endif // LIBGAV1_SRC_QUANTIZER_H_
|
