| /* 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_ */ |