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-rw-r--r-- | third_party/libwebrtc/modules/audio_coding/neteq/cross_correlation.h | 51 |
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diff --git a/third_party/libwebrtc/modules/audio_coding/neteq/cross_correlation.h b/third_party/libwebrtc/modules/audio_coding/neteq/cross_correlation.h new file mode 100644 index 0000000000..5082ce6a30 --- /dev/null +++ b/third_party/libwebrtc/modules/audio_coding/neteq/cross_correlation.h @@ -0,0 +1,51 @@ +/* + * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ + +#ifndef MODULES_AUDIO_CODING_NETEQ_CROSS_CORRELATION_H_ +#define MODULES_AUDIO_CODING_NETEQ_CROSS_CORRELATION_H_ + +#include <stddef.h> +#include <stdint.h> + +namespace webrtc { + +// The function calculates the cross-correlation between two sequences +// `sequence_1` and `sequence_2`. `sequence_1` is taken as reference, with +// `sequence_1_length` as its length. `sequence_2` slides for the calculation of +// cross-correlation. The result will be saved in `cross_correlation`. +// `cross_correlation_length` correlation points are calculated. +// The corresponding lag starts from 0, and increases with a step of +// `cross_correlation_step`. The result is without normalization. To avoid +// overflow, the result will be right shifted. The amount of shifts will be +// returned. +// +// Input: +// - sequence_1 : First sequence (reference). +// - sequence_2 : Second sequence (sliding during calculation). +// - sequence_1_length : Length of `sequence_1`. +// - cross_correlation_length : Number of cross-correlations to calculate. +// - cross_correlation_step : Step in the lag for the cross-correlation. +// +// Output: +// - cross_correlation : The cross-correlation in Q(-right_shifts) +// +// Return: +// Number of right shifts in cross_correlation. + +int CrossCorrelationWithAutoShift(const int16_t* sequence_1, + const int16_t* sequence_2, + size_t sequence_1_length, + size_t cross_correlation_length, + int cross_correlation_step, + int32_t* cross_correlation); + +} // namespace webrtc + +#endif // MODULES_AUDIO_CODING_NETEQ_CROSS_CORRELATION_H_ |