| /* |
| * 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/segmentation.h" |
| #include "src/utils/types.h" |
| |
| namespace libgav1 { |
| |
| // 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_; |
| }; |
| |
| // 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_ |