202 lines
7.4 KiB
C
202 lines
7.4 KiB
C
/*
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* FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
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* Copyright (C) 2005-2021, Anthony Minessale II <anthm@freeswitch.org>
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*
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* Version: MPL 1.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
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*
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* The Initial Developer of the Original Code is
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* Anthony Minessale II <anthm@freeswitch.org>
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* Portions created by the Initial Developer are Copyright (C)
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Anthony Minessale II <anthm@freeswitch.org>
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*
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*
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* switch_resample.h
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*
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*/
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/*! \file switch_resample.h
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\brief Audio Resample Code
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This module implements a generic interface for doing audio resampling it currently uses libresample but can be ported to
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any resample library with a little effort. I decided against making this interface pluggable because there are not many
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options in terms of resample libraries so it seemed like a waste but I did opt to frontend the interface in case a better
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way comes along some day. =D
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*/
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#define switch_normalize_volume(x) if (x > 4) x = 4; if (x < -4) x = -4;
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#define SWITCH_GRANULAR_VOLUME_MAX 50
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#define switch_normalize_volume_granular(x) if (x > SWITCH_GRANULAR_VOLUME_MAX) x = SWITCH_GRANULAR_VOLUME_MAX; if (x < -SWITCH_GRANULAR_VOLUME_MAX) x = -SWITCH_GRANULAR_VOLUME_MAX;
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#ifndef SWITCH_RESAMPLE_H
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#define SWITCH_RESAMPLE_H
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#define SWITCH_RESAMPLE_QUALITY 2
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#include <switch.h>
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SWITCH_BEGIN_EXTERN_C
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/*!
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\defgroup resamp Audio Resample Functions
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\ingroup core1
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\{
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*/
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/*! \brief An audio resampling handle */
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typedef struct {
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/*! a pointer to store the resampler object */
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void *resampler;
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/*! the rate to resample from in hz */
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int from_rate;
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/*! the rate to resample to in hz */
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int to_rate;
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/*! the factor to resample by (from / to) */
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double factor;
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double rfactor;
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int16_t *to;
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/*! the size of the to buffer used */
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uint32_t to_len;
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/*! the total size of the to buffer */
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uint32_t to_size;
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/*! the number of channels */
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int channels;
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} switch_audio_resampler_t;
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/*!
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\brief Prepare a new resampler handle
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\param new_resampler NULL pointer to aim at the new handle
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\param from_rate the rate to transfer from in hz
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\param to_rate the rate to transfer to in hz
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\param quality the quality desired
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\return SWITCH_STATUS_SUCCESS if the handle was created
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*/
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SWITCH_DECLARE(switch_status_t) switch_resample_perform_create(switch_audio_resampler_t **new_resampler,
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uint32_t from_rate, uint32_t to_rate, uint32_t to_size,
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int quality, uint32_t channels, const char *file, const char *func, int line);
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#define switch_resample_create(_n, _fr, _tr, _ts, _q, _c) switch_resample_perform_create(_n, _fr, _tr, _ts, _q, _c, __FILE__, __SWITCH_FUNC__, __LINE__)
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/*!
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\brief Destroy an existing resampler handle
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\param resampler the resampler handle to destroy
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*/
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SWITCH_DECLARE(void) switch_resample_destroy(switch_audio_resampler_t **resampler);
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/*!
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\brief Resample one float buffer into another using specifications of a given handle
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\param resampler the resample handle
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\param src the source data
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\param srclen the length of the source data
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\return the used size of dst
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*/
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SWITCH_DECLARE(uint32_t) switch_resample_process(switch_audio_resampler_t *resampler, int16_t *src, uint32_t srclen);
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/*!
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\brief Convert an array of floats to an array of shorts
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\param f the float buffer
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\param s the short buffer
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\param len the length of the buffers
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\return the size of the converted buffer
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*/
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SWITCH_DECLARE(switch_size_t) switch_float_to_short(float *f, short *s, switch_size_t len);
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/*!
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\brief Convert an array of chars to an array of floats
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\param c the char buffer
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\param f the float buffer
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\param len the length of the buffers
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\return the size of the converted buffer
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*/
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SWITCH_DECLARE(int) switch_char_to_float(char *c, float *f, int len);
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/*!
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\brief Convert an array of floats to an array of chars
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\param f an array of floats
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\param c an array of chars
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\param len the length of the buffers
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\return the size of the converted buffer
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*/
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SWITCH_DECLARE(int) switch_float_to_char(float *f, char *c, int len);
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/*!
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\brief Convert an array of shorts to an array of floats
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\param s an array of shorts
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\param f an array of floats
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\param len the size of the buffers
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\return the size of the converted buffer
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*/
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SWITCH_DECLARE(int) switch_short_to_float(short *s, float *f, int len);
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/*!
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\brief Perform a byteswap on a buffer of 16 bit samples
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\param buf an array of samples
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\param len the size of the array
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*/
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SWITCH_DECLARE(void) switch_swap_linear(int16_t *buf, int len);
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/*!
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\brief Generate static noise
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\param data the audio data buffer
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\param samples the number of 2 byte samples
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\param divisor the volume factor
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*/
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SWITCH_DECLARE(void) switch_generate_sln_silence(int16_t *data, uint32_t samples, uint32_t channels, uint32_t divisor);
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/*!
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\brief Change the volume of a signed linear audio frame
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\param data the audio data
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\param samples the number of 2 byte samples
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\param vol the volume factor -4 -> 4
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*/
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SWITCH_DECLARE(void) switch_change_sln_volume(int16_t *data, uint32_t samples, int32_t vol);
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/*!
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\brief Change the volume of a signed linear audio frame with more granularity
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\param data the audio data
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\param samples the number of 2 byte samples
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\param vol the volume factor -12 -> 12
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*/
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SWITCH_DECLARE(void) switch_change_sln_volume_granular(int16_t *data, uint32_t samples, int32_t vol);
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///\}
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SWITCH_DECLARE(uint32_t) switch_merge_sln(int16_t *data, uint32_t samples, int16_t *other_data, uint32_t other_samples, int channels);
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SWITCH_DECLARE(uint32_t) switch_unmerge_sln(int16_t *data, uint32_t samples, int16_t *other_data, uint32_t other_samples, int channels);
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SWITCH_DECLARE(void) switch_mux_channels(int16_t *data, switch_size_t samples, uint32_t orig_channels, uint32_t channels);
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#define switch_resample_calc_buffer_size(_to, _from, _srclen) ((uint32_t)(((float)_to / (float)_from) * (float)_srclen) * 2)
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SWITCH_DECLARE(void) switch_agc_set(switch_agc_t *agc, uint32_t energy_avg,
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uint32_t low_energy_point, uint32_t margin, uint32_t change_factor, uint32_t period_len);
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SWITCH_DECLARE(switch_status_t) switch_agc_create(switch_agc_t **agcP, uint32_t energy_avg,
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uint32_t low_energy_point, uint32_t margin, uint32_t change_factor, uint32_t period_len);
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SWITCH_DECLARE(void) switch_agc_destroy(switch_agc_t **agcP);
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SWITCH_DECLARE(switch_status_t) switch_agc_feed(switch_agc_t *agc, int16_t *data, uint32_t samples, uint32_t channels);
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SWITCH_DECLARE(void) switch_agc_set_energy_avg(switch_agc_t *agc, uint32_t energy_avg);
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SWITCH_DECLARE(void) switch_agc_set_energy_low(switch_agc_t *agc, uint32_t low_energy_point);
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SWITCH_DECLARE(void) switch_agc_set_token(switch_agc_t *agc, const char *token);
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SWITCH_END_EXTERN_C
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#endif
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/* For Emacs:
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* Local Variables:
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* mode:c
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* indent-tabs-mode:t
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* tab-width:4
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* c-basic-offset:4
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* End:
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* For VIM:
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* vim:set softtabstop=4 shiftwidth=4 tabstop=4 noet:
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*/
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