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/* Copyright (c) 2013 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.
*/
#ifndef EQ2_H_
#define EQ2_H_
#ifdef __cplusplus
extern "C" {
#endif
/* "eq2" is a two channel version of the "eq" filter. It processes two channels
* of data at once to increase performance. */
#include "biquad.h"
/* Maximum number of biquad filters an EQ2 can have per channel */
#define MAX_BIQUADS_PER_EQ2 10
struct eq2;
/* Create an EQ2. */
struct eq2 *eq2_new();
/* Free an EQ2. */
void eq2_free(struct eq2 *eq2);
/* Append a biquad filter to an EQ2. An EQ2 can have at most MAX_BIQUADS_PER_EQ2
* biquad filters per channel.
* Args:
* eq2 - The EQ2 we want to use.
* channel - 0 or 1. The channel we want to append the filter to.
* type - The type of the biquad filter we want to append.
* frequency - The value should be in the range [0, 1]. It is relative to
* half of the sampling rate.
* Q, gain - The meaning depends on the type of the filter. See Web Audio
* API for details.
* Returns:
* 0 if success. -1 if the eq has no room for more biquads.
*/
int eq2_append_biquad(struct eq2 *eq2, int channel, enum biquad_type type,
float freq, float Q, float gain);
/* Append a biquad filter to an EQ2. An EQ2 can have at most MAX_BIQUADS_PER_EQ2
* biquad filters. This is similar to eq2_append_biquad(), but it specifies the
* biquad coefficients directly.
* Args:
* eq2 - The EQ2 we want to use.
* channel - 0 or 1. The channel we want to append the filter to.
* biquad - The parameters for the biquad filter.
* Returns:
* 0 if success. -1 if the eq has no room for more biquads.
*/
int eq2_append_biquad_direct(struct eq2 *eq2, int channel,
const struct biquad *biquad);
/* Process a buffer of audio data through the EQ2.
* Args:
* eq2 - The EQ2 we want to use.
* data0 - The array of channel 0 audio samples.
* data1 - The array of channel 1 audio samples.
* count - The number of elements in each of the data array to process.
*/
void eq2_process(struct eq2 *eq2, float *data0, float *data1, int count);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* EQ2_H_ */
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