minyue | 53ff70f | 2016-05-02 08:50:30 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
Mirko Bonadei | 92ea95e | 2017-09-15 04:47:31 | [diff] [blame] | 11 | #ifndef MODULES_AUDIO_CODING_NETEQ_CROSS_CORRELATION_H_ |
| 12 | #define MODULES_AUDIO_CODING_NETEQ_CROSS_CORRELATION_H_ |
minyue | 53ff70f | 2016-05-02 08:50:30 | [diff] [blame] | 13 | |
Yves Gerey | 988cc08 | 2018-10-23 10:03:01 | [diff] [blame] | 14 | #include <stddef.h> |
| 15 | #include <stdint.h> |
minyue | 53ff70f | 2016-05-02 08:50:30 | [diff] [blame] | 16 | |
| 17 | namespace webrtc { |
| 18 | |
| 19 | // The function calculates the cross-correlation between two sequences |
| 20 | // |sequence_1| and |sequence_2|. |sequence_1| is taken as reference, with |
| 21 | // |sequence_1_length| as its length. |sequence_2| slides for the calculation of |
| 22 | // cross-correlation. The result will be saved in |cross_correlation|. |
| 23 | // |cross_correlation_length| correlation points are calculated. |
| 24 | // The corresponding lag starts from 0, and increases with a step of |
| 25 | // |cross_correlation_step|. The result is without normalization. To avoid |
| 26 | // overflow, the result will be right shifted. The amount of shifts will be |
| 27 | // returned. |
| 28 | // |
| 29 | // Input: |
| 30 | // - sequence_1 : First sequence (reference). |
| 31 | // - sequence_2 : Second sequence (sliding during calculation). |
| 32 | // - sequence_1_length : Length of |sequence_1|. |
| 33 | // - cross_correlation_length : Number of cross-correlations to calculate. |
| 34 | // - cross_correlation_step : Step in the lag for the cross-correlation. |
| 35 | // |
| 36 | // Output: |
| 37 | // - cross_correlation : The cross-correlation in Q(-right_shifts) |
| 38 | // |
| 39 | // Return: |
| 40 | // Number of right shifts in cross_correlation. |
| 41 | |
| 42 | int CrossCorrelationWithAutoShift(const int16_t* sequence_1, |
| 43 | const int16_t* sequence_2, |
| 44 | size_t sequence_1_length, |
| 45 | size_t cross_correlation_length, |
| 46 | int cross_correlation_step, |
| 47 | int32_t* cross_correlation); |
| 48 | |
| 49 | } // namespace webrtc |
| 50 | |
Mirko Bonadei | 92ea95e | 2017-09-15 04:47:31 | [diff] [blame] | 51 | #endif // MODULES_AUDIO_CODING_NETEQ_CROSS_CORRELATION_H_ |