1 /* Copyright (c) 2014 The Chromium OS Authors. All rights reserved. 2 * Use of this source code is governed by a BSD-style license that can be 3 * found in the LICENSE file. 4 */ 5 6 #ifndef LINEAR_RESAMPLER_H_ 7 #define LINEAR_RESAMPLER_H_ 8 9 10 struct linear_resampler; 11 12 /* Creates a linear resampler. 13 * Args: 14 * num_channels - The number of channels in each frames. 15 * format_bytes - The length of one frame in bytes. 16 * src_rate - The source rate to resample from. 17 * dst_rate - The destination rate to resample to. 18 */ 19 struct linear_resampler *linear_resampler_create(unsigned int num_channels, 20 unsigned int format_bytes, 21 float src_rate, 22 float dst_rate); 23 24 /* Sets the rates for the linear resampler. 25 * Args: 26 * from - The rate to resample from. 27 * to - The rate to resample to. 28 */ 29 void linear_resampler_set_rates(struct linear_resampler *lr, 30 float from, 31 float to); 32 33 /* Converts the frames count from output rate to input rate. */ 34 unsigned int linear_resampler_out_frames_to_in(struct linear_resampler *lr, 35 unsigned int frames); 36 37 /* Converts the frames count from input rate to output rate. */ 38 unsigned int linear_resampler_in_frames_to_out(struct linear_resampler *lr, 39 unsigned int frames); 40 41 /* Returns true if SRC is needed, otherwise return false. */ 42 int linear_resampler_needed(struct linear_resampler *lr); 43 44 /* Run linear resample for audio samples. 45 * Args: 46 * lr - The linear resampler. 47 * src - The input buffer. 48 * src_frames - The number of frames of input buffer. 49 * dst - The output buffer. 50 * dst_frames - The number of frames of output buffer. 51 */ 52 unsigned int linear_resampler_resample(struct linear_resampler *lr, 53 uint8_t *src, 54 unsigned int *src_frames, 55 uint8_t *dst, 56 unsigned dst_frames); 57 58 /* Destroy a linear resampler. */ 59 void linear_resampler_destroy(struct linear_resampler *lr); 60 61 #endif /* LINEAR_RESAMPLER_H_ */ 62
