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d00ce747c7
Bug: webrtc:12338 Change-Id: I02613d9fca45d00e2477f334b7a0416e7912e26b Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227037 Reviewed-by: Harald Alvestrand <hta@webrtc.org> Commit-Queue: Artem Titov <titovartem@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34621}
51 lines
2.1 KiB
C++
51 lines
2.1 KiB
C++
/*
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* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef MODULES_AUDIO_CODING_NETEQ_CROSS_CORRELATION_H_
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#define MODULES_AUDIO_CODING_NETEQ_CROSS_CORRELATION_H_
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#include <stddef.h>
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#include <stdint.h>
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namespace webrtc {
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// The function calculates the cross-correlation between two sequences
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// `sequence_1` and `sequence_2`. `sequence_1` is taken as reference, with
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// `sequence_1_length` as its length. `sequence_2` slides for the calculation of
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// cross-correlation. The result will be saved in `cross_correlation`.
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// `cross_correlation_length` correlation points are calculated.
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// The corresponding lag starts from 0, and increases with a step of
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// `cross_correlation_step`. The result is without normalization. To avoid
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// overflow, the result will be right shifted. The amount of shifts will be
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// returned.
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//
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// Input:
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// - sequence_1 : First sequence (reference).
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// - sequence_2 : Second sequence (sliding during calculation).
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// - sequence_1_length : Length of `sequence_1`.
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// - cross_correlation_length : Number of cross-correlations to calculate.
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// - cross_correlation_step : Step in the lag for the cross-correlation.
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//
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// Output:
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// - cross_correlation : The cross-correlation in Q(-right_shifts)
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//
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// Return:
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// Number of right shifts in cross_correlation.
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int CrossCorrelationWithAutoShift(const int16_t* sequence_1,
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const int16_t* sequence_2,
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size_t sequence_1_length,
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size_t cross_correlation_length,
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int cross_correlation_step,
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int32_t* cross_correlation);
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} // namespace webrtc
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#endif // MODULES_AUDIO_CODING_NETEQ_CROSS_CORRELATION_H_
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