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// Copyright 2019 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Generated from files in cras/src/server/rust/src in adhd.
#ifndef RATE_ESTIMATOR_H_
#define RATE_ESTIMATOR_H_
#include <time.h>
/**
* An estimator holding the required information to determine the actual frame
* rate of an audio device.
*
* # Members
* * `last_level` - Buffer level of the audio device at last check time.
* * `level_diff` - Number of frames written to or read from audio device
* since the last check time. Rate estimator will use this
* change plus the difference of buffer level to derive the
* number of frames audio device has actually processed.
* * `window_start` - The start time of the current window.
* * `window_size` - The size of the window.
* * `window_frames` - The number of frames accumulated in current window.
* * `lsq` - The helper used to estimate sample rate.
* * `smooth_factor` - A scaling factor used to average the previous and new
* rate estimates to ensure that estimates do not change
* too quickly.
* * `estimated_rate` - The estimated rate at which samples are consumed.
*/
typedef struct rate_estimator rate_estimator;
/**
* # Safety
*
* To use this function safely, `re` must be a pointer returned from
* rate_estimator_create, or null.
*/
void rate_estimator_add_frames(rate_estimator *re, int frames);
/**
* # Safety
*
* To use this function safely, `re` must be a pointer returned from
* rate_estimator_create, or null, and `now` must be a valid pointer to a
* timespec.
*/
int32_t rate_estimator_check(rate_estimator *re, int level,
const struct timespec *now);
/**
* # Safety
*
* To use this function safely, `window_size` must be a valid pointer to a
* timespec.
*/
rate_estimator *rate_estimator_create(unsigned int rate,
const struct timespec *window_size,
double smooth_factor);
/**
* # Safety
*
* To use this function safely, `re` must be a pointer returned from
* rate_estimator_create, or null.
*/
void rate_estimator_destroy(rate_estimator *re);
/**
* # Safety
*
* To use this function safely, `re` must be a pointer returned from
* rate_estimator_create, or null.
*/
double rate_estimator_get_rate(const rate_estimator *re);
/**
* # Safety
*
* To use this function safely, `re` must be a pointer returned from
* rate_estimator_create, or null.
*/
void rate_estimator_reset_rate(rate_estimator *re, unsigned int rate);
#endif /* RATE_ESTIMATOR_H_ */
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