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673 lines
26 KiB
C
673 lines
26 KiB
C
/* Vocoder Library
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* Voclib version 1.1 - 2019-02-16
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*
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* Philip Bennefall - philip@blastbay.com
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*
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* See the end of this file for licensing terms.
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* The filter implementation was derived from public domain code found on musicdsp.org (see the section called "Filters" for more details).
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*
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* USAGE
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*
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* This is a single-file library. To use it, do something like the following in one .c file.
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* #define VOCLIB_IMPLEMENTATION
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* #include "voclib.h"
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*
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* You can then #include this file in other parts of the program as you would with any other header file.
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*/
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#ifndef VOCLIB_H
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#define VOCLIB_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* COMPILE-TIME OPTIONS */
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/* The maximum number of bands that the vocoder can be initialized with (lower this number to save memory). */
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#define VOCLIB_MAX_BANDS 96
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/* The maximum number of filters per vocoder band (lower this number to save memory). */
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#define VOCLIB_MAX_FILTERS_PER_BAND 8
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/* PUBLIC API */
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typedef struct voclib_instance voclib_instance;
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/* Initialize a voclib_instance structure.
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*
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* Call this function to initialize the voclib_instance structure.
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* bands is the number of bands that the vocoder should use; recommended values are between 12 and 64.
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* bands must be between 4 and VOCLIB_MAX_BANDS (inclusive).
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* filters_per_band determines the steapness with which the filterbank divides the signal; a value of 6 is recommended.
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* filters_per_band must be between 1 and VOCLIB_MAX_FILTERS_PER_BAND (inclusive).
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* sample_rate is the number of samples per second in hertz, and should be between 8000 and 192000 (inclusive).
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* carrier_channels is the number of channels that the carrier has, and should be between 1 and 2 (inclusive).
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* Note: The modulator must always have only one channel.
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* Returns nonzero (true) on success or 0 (false) on failure.
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* The function will only fail if one or more of the parameters are invalid.
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*/
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int voclib_initialize ( voclib_instance* instance, unsigned char bands, unsigned char filters_per_band, unsigned int sample_rate, unsigned char carrier_channels );
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/* Run the vocoder.
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*
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* Call this function continuously to generate your output.
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* carrier_buffer and modulator_buffer should contain the carrier and modulator signals respectively.
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* The modulator must always have one channel.
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* If the carrier has two channels, the samples in carrier_buffer must be interleaved.
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* output_buffer will be filled with the result, and must be able to hold as many channels as the carrier.
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* If the carrier has two channels, the output buffer will be filled with interleaved samples.
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* output_buffer may be the same pointer as either carrier_buffer or modulator_buffer as long as it can hold the same number of channels as the carrier.
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* The processing is performed in place.
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* frames specifies the number of sample frames that should be processed.
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* Returns nonzero (true) on success or 0 (false) on failure.
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* The function will only fail if one or more of the parameters are invalid.
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*/
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int voclib_process ( voclib_instance* instance, const float* carrier_buffer, const float* modulator_buffer, float* output_buffer, unsigned int frames );
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/* Reset the vocoder sample history.
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*
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* In order to run smoothly, the vocoder needs to store a few recent samples internally.
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* This function resets that internal history. This should only be done if you are processing a new stream.
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* Resetting the history in the middle of a stream will cause clicks.
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*/
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void voclib_reset_history ( voclib_instance* instance );
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/* Set the reaction time of the vocoder in seconds.
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*
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* The reaction time is the time it takes for the vocoder to respond to a volume change in the modulator.
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* A value of 0.03 (AKA 30 milliseconds) is recommended for intelligible speech.
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* Values lower than about 0.02 will make the output sound raspy and unpleasant.
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* Values above 0.2 or so will make the speech hard to understand, but can be used for special effects.
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* The value must be between 0.002 and 2.0 (inclusive).
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* Returns nonzero (true) on success or 0 (false) on failure.
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* The function will only fail if the parameter is invalid.
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*/
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int voclib_set_reaction_time ( voclib_instance* instance, float reaction_time );
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/* Get the current reaction time of the vocoder in seconds. */
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float voclib_get_reaction_time ( const voclib_instance* instance );
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/* Set the formant shift of the vocoder in octaves.
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*
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* Formant shifting changes the size of the speaker's head.
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* A value of 1.0 leaves the head size unmodified.
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* Values lower than 1.0 make the head larger, and values above 1.0 make it smaller.
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* The value must be between 0.25 and 4.0 (inclusive).
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* Returns nonzero (true) on success or 0 (false) on failure.
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* The function will only fail if the parameter is invalid.
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*/
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int voclib_set_formant_shift ( voclib_instance* instance, float formant_shift );
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/* Get the current formant shift of the vocoder in octaves. */
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float voclib_get_formant_shift ( const voclib_instance* instance );
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/* INTERNAL STRUCTURES */
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/* this holds the data required to update samples thru a filter. */
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typedef struct
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{
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float a0, a1, a2, a3, a4;
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float x1, x2, y1, y2;
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} voclib_biquad;
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/* Stores the state required for our envelope follower. */
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typedef struct
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{
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float coef;
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float history[4];
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} voclib_envelope;
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/* Holds a set of filters required for one vocoder band. */
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typedef struct
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{
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voclib_biquad filters[VOCLIB_MAX_FILTERS_PER_BAND];
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} voclib_band;
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/* The main instance structure. This is the structure that you will create an instance of when using the vocoder. */
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struct voclib_instance
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{
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voclib_band analysis_bands[VOCLIB_MAX_BANDS]; /* The filterbank used for analysis (these are applied to the modulator). */
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voclib_envelope analysis_envelopes[VOCLIB_MAX_BANDS]; /* The envelopes used to smooth the analysis bands. */
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voclib_band synthesis_bands[VOCLIB_MAX_BANDS * 2]; /* The filterbank used for synthesis (these are applied to the carrier). The second half of the array is only used for stereo carriers. */
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float reaction_time; /* In seconds. Higher values make the vocoder respond more slowly to changes in the modulator. */
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float formant_shift; /* In octaves. 1.0 is unchanged. */
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unsigned int sample_rate; /* In hertz. */
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unsigned char bands;
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unsigned char filters_per_band;
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unsigned char carrier_channels;
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};
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#ifdef __cplusplus
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}
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#endif
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#endif /* VOCLIB_H */
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/* IMPLEMENTATION */
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#ifdef VOCLIB_IMPLEMENTATION
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#include <math.h>
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#include <assert.h>
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#ifdef _MSC_VER
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#define VOCLIB_INLINE __forceinline
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#else
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#ifdef __GNUC__
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#define VOCLIB_INLINE inline __attribute__((always_inline))
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#else
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#define VOCLIB_INLINE inline
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#endif
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#endif
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/* Filters
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*
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* The filter code below was derived from http://www.musicdsp.org/files/biquad.c. The comment at the top of biquad.c file reads:
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*
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* Simple implementation of Biquad filters -- Tom St Denis
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*
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* Based on the work
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Cookbook formulae for audio EQ biquad filter coefficients
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---------------------------------------------------------
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by Robert Bristow-Johnson, pbjrbj@viconet.com a.k.a. robert@audioheads.com
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* Available on the web at
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http://www.smartelectronix.com/musicdsp/text/filters005.txt
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* Enjoy.
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*
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* This work is hereby placed in the public domain for all purposes, whether
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* commercial, free [as in speech] or educational, etc. Use the code and please
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* give me credit if you wish.
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*
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* Tom St Denis -- http://tomstdenis.home.dhs.org
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*/
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#ifndef VOCLIB_M_LN2
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#define VOCLIB_M_LN2 0.69314718055994530942
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#endif
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#ifndef VOCLIB_M_PI
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#define VOCLIB_M_PI 3.14159265358979323846
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#endif
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/* Computes a BiQuad filter on a sample. */
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static VOCLIB_INLINE float voclib_BiQuad ( float sample, voclib_biquad* b )
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{
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float result;
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/* compute the result. */
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result = b->a0 * sample + b->a1 * b->x1 + b->a2 * b->x2 -
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b->a3 * b->y1 - b->a4 * b->y2;
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/* shift x1 to x2, sample to x1. */
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b->x2 = b->x1;
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b->x1 = sample;
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/* shift y1 to y2, result to y1. */
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b->y2 = b->y1;
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b->y1 = result;
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return result;
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}
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/* filter types. */
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enum
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{
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VOCLIB_LPF, /* low pass filter */
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VOCLIB_HPF, /* High pass filter */
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VOCLIB_BPF, /* band pass filter */
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VOCLIB_NOTCH, /* Notch Filter */
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VOCLIB_PEQ, /* Peaking band EQ filter */
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VOCLIB_LSH, /* Low shelf filter */
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VOCLIB_HSH /* High shelf filter */
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};
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/* sets up a BiQuad Filter. */
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static void voclib_BiQuad_new ( voclib_biquad* b, int type, float dbGain, /* gain of filter */
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float freq, /* center frequency */
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float srate, /* sampling rate */
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float bandwidth ) /* bandwidth in octaves */
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{
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float A, omega, sn, cs, alpha, beta;
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float a0, a1, a2, b0, b1, b2;
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/* setup variables. */
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A = ( float ) pow ( 10, dbGain / 40.0f );
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omega = ( float ) ( 2.0 * VOCLIB_M_PI * freq / srate );
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sn = ( float ) sin ( omega );
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cs = ( float ) cos ( omega );
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alpha = sn * ( float ) sinh ( VOCLIB_M_LN2 / 2 * bandwidth * omega / sn );
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beta = ( float ) sqrt ( A + A );
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switch ( type )
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{
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case VOCLIB_LPF:
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b0 = ( 1 - cs ) / 2;
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b1 = 1 - cs;
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b2 = ( 1 - cs ) / 2;
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a0 = 1 + alpha;
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a1 = -2 * cs;
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a2 = 1 - alpha;
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break;
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case VOCLIB_HPF:
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b0 = ( 1 + cs ) / 2;
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b1 = - ( 1 + cs );
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b2 = ( 1 + cs ) / 2;
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a0 = 1 + alpha;
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a1 = -2 * cs;
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a2 = 1 - alpha;
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break;
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case VOCLIB_BPF:
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b0 = alpha;
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b1 = 0;
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b2 = -alpha;
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a0 = 1 + alpha;
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a1 = -2 * cs;
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a2 = 1 - alpha;
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break;
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case VOCLIB_NOTCH:
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b0 = 1;
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b1 = -2 * cs;
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b2 = 1;
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a0 = 1 + alpha;
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a1 = -2 * cs;
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a2 = 1 - alpha;
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break;
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case VOCLIB_PEQ:
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b0 = 1 + ( alpha * A );
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b1 = -2 * cs;
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b2 = 1 - ( alpha * A );
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a0 = 1 + ( alpha / A );
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a1 = -2 * cs;
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a2 = 1 - ( alpha / A );
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break;
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case VOCLIB_LSH:
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b0 = A * ( ( A + 1 ) - ( A - 1 ) * cs + beta * sn );
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b1 = 2 * A * ( ( A - 1 ) - ( A + 1 ) * cs );
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b2 = A * ( ( A + 1 ) - ( A - 1 ) * cs - beta * sn );
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a0 = ( A + 1 ) + ( A - 1 ) * cs + beta * sn;
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a1 = -2 * ( ( A - 1 ) + ( A + 1 ) * cs );
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a2 = ( A + 1 ) + ( A - 1 ) * cs - beta * sn;
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break;
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case VOCLIB_HSH:
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b0 = A * ( ( A + 1 ) + ( A - 1 ) * cs + beta * sn );
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b1 = -2 * A * ( ( A - 1 ) + ( A + 1 ) * cs );
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b2 = A * ( ( A + 1 ) + ( A - 1 ) * cs - beta * sn );
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a0 = ( A + 1 ) - ( A - 1 ) * cs + beta * sn;
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a1 = 2 * ( ( A - 1 ) - ( A + 1 ) * cs );
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a2 = ( A + 1 ) - ( A - 1 ) * cs - beta * sn;
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break;
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default:
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assert ( 0 ); /* Misuse. */
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return;
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}
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/* precompute the coefficients. */
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b->a0 = b0 / a0;
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b->a1 = b1 / a0;
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b->a2 = b2 / a0;
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b->a3 = a1 / a0;
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b->a4 = a2 / a0;
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}
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/* Reset the filter history. */
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static void voclib_BiQuad_reset ( voclib_biquad* b )
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{
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b->x1 = b->x2 = 0.0f;
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b->y1 = b->y2 = 0.0f;
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}
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/* Envelope follower. */
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static void voclib_envelope_configure ( voclib_envelope* envelope, double time_in_seconds, double sample_rate )
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{
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envelope->coef = ( float ) ( pow ( 0.01, 1.0 / ( time_in_seconds * sample_rate ) ) );
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}
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/* Reset the envelope history. */
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static void voclib_envelope_reset ( voclib_envelope* envelope )
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{
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envelope->history[0] = 0.0f;
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envelope->history[1] = 0.0f;
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envelope->history[2] = 0.0f;
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envelope->history[3] = 0.0f;
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}
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static VOCLIB_INLINE float voclib_envelope_tick ( voclib_envelope* envelope, float sample )
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{
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const float coef = envelope->coef;
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envelope->history[0] = ( float ) ( ( 1.0f - coef ) * fabs ( sample ) ) + ( coef * envelope->history[0] );
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envelope->history[1] = ( ( 1.0f - coef ) * envelope->history[0] ) + ( coef * envelope->history[1] );
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envelope->history[2] = ( ( 1.0f - coef ) * envelope->history[1] ) + ( coef * envelope->history[2] );
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envelope->history[3] = ( ( 1.0f - coef ) * envelope->history[2] ) + ( coef * envelope->history[3] );
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return envelope->history[3];
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}
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/* Initialize the vocoder filterbank. */
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static void voclib_initialize_filterbank ( voclib_instance* instance, int carrier_only )
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{
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unsigned char i;
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double step;
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double lastfreq = 0.0;
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double minfreq = 80.0;
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double maxfreq = instance->sample_rate;
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if ( maxfreq > 12000.0 )
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{
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maxfreq = 12000.0;
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}
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step = pow ( ( maxfreq / minfreq ), ( 1.0 / instance->bands ) );
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for ( i = 0; i < instance->bands; ++i )
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{
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unsigned char i2;
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double bandwidth, nextfreq;
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double priorfreq = lastfreq;
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if ( lastfreq > 0.0 )
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{
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lastfreq *= step;
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}
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else
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{
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lastfreq = minfreq;
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}
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nextfreq = lastfreq * step;
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bandwidth = ( nextfreq - priorfreq ) / lastfreq;
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if ( !carrier_only )
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{
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voclib_BiQuad_new ( &instance->analysis_bands[i].filters[0], VOCLIB_BPF, 0.0f, ( float ) lastfreq, ( float ) instance->sample_rate, ( float ) bandwidth );
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for ( i2 = 1; i2 < instance->filters_per_band; ++i2 )
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{
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instance->analysis_bands[i].filters[i2].a0 = instance->analysis_bands[i].filters[0].a0;
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instance->analysis_bands[i].filters[i2].a1 = instance->analysis_bands[i].filters[0].a1;
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instance->analysis_bands[i].filters[i2].a2 = instance->analysis_bands[i].filters[0].a2;
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instance->analysis_bands[i].filters[i2].a3 = instance->analysis_bands[i].filters[0].a3;
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instance->analysis_bands[i].filters[i2].a4 = instance->analysis_bands[i].filters[0].a4;
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}
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}
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if ( instance->formant_shift != 1.0f )
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{
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voclib_BiQuad_new ( &instance->synthesis_bands[i].filters[0], VOCLIB_BPF, 0.0f, ( float ) ( lastfreq * instance->formant_shift ), ( float ) instance->sample_rate, ( float ) bandwidth );
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}
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else
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{
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instance->synthesis_bands[i].filters[0].a0 = instance->analysis_bands[i].filters[0].a0;
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instance->synthesis_bands[i].filters[0].a1 = instance->analysis_bands[i].filters[0].a1;
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instance->synthesis_bands[i].filters[0].a2 = instance->analysis_bands[i].filters[0].a2;
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instance->synthesis_bands[i].filters[0].a3 = instance->analysis_bands[i].filters[0].a3;
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instance->synthesis_bands[i].filters[0].a4 = instance->analysis_bands[i].filters[0].a4;
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}
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instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[0].a0 = instance->synthesis_bands[i].filters[0].a0;
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instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[0].a1 = instance->synthesis_bands[i].filters[0].a1;
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instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[0].a2 = instance->synthesis_bands[i].filters[0].a2;
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instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[0].a3 = instance->synthesis_bands[i].filters[0].a3;
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instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[0].a4 = instance->synthesis_bands[i].filters[0].a4;
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for ( i2 = 1; i2 < instance->filters_per_band; ++i2 )
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{
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instance->synthesis_bands[i].filters[i2].a0 = instance->synthesis_bands[i].filters[0].a0;
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instance->synthesis_bands[i].filters[i2].a1 = instance->synthesis_bands[i].filters[0].a1;
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instance->synthesis_bands[i].filters[i2].a2 = instance->synthesis_bands[i].filters[0].a2;
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instance->synthesis_bands[i].filters[i2].a3 = instance->synthesis_bands[i].filters[0].a3;
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instance->synthesis_bands[i].filters[i2].a4 = instance->synthesis_bands[i].filters[0].a4;
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instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[i2].a0 = instance->synthesis_bands[i].filters[0].a0;
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instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[i2].a1 = instance->synthesis_bands[i].filters[0].a1;
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instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[i2].a2 = instance->synthesis_bands[i].filters[0].a2;
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instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[i2].a3 = instance->synthesis_bands[i].filters[0].a3;
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instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[i2].a4 = instance->synthesis_bands[i].filters[0].a4;
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}
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}
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}
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/* Initialize the vocoder envelopes. */
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static void voclib_initialize_envelopes ( voclib_instance* instance )
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{
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unsigned char i;
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|
|
voclib_envelope_configure ( &instance->analysis_envelopes[0], instance->reaction_time, ( double ) instance->sample_rate );
|
|
for ( i = 1; i < instance->bands; ++i )
|
|
{
|
|
instance->analysis_envelopes[i].coef = instance->analysis_envelopes[0].coef;
|
|
}
|
|
}
|
|
|
|
int voclib_initialize ( voclib_instance* instance, unsigned char bands, unsigned char filters_per_band, unsigned int sample_rate, unsigned char carrier_channels )
|
|
{
|
|
if ( !instance )
|
|
{
|
|
return 0;
|
|
}
|
|
if ( bands < 4 || bands > VOCLIB_MAX_BANDS )
|
|
{
|
|
return 0;
|
|
}
|
|
if ( filters_per_band < 1 || filters_per_band > VOCLIB_MAX_FILTERS_PER_BAND )
|
|
{
|
|
return 0;
|
|
}
|
|
if ( sample_rate < 8000 || sample_rate > 192000 )
|
|
{
|
|
return 0;
|
|
}
|
|
if ( carrier_channels < 1 || carrier_channels > 2 )
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
instance->reaction_time = 0.03f;
|
|
instance->formant_shift = 1.0f;
|
|
instance->sample_rate = sample_rate;
|
|
instance->bands = bands;
|
|
instance->filters_per_band = filters_per_band;
|
|
instance->carrier_channels = carrier_channels;
|
|
|
|
voclib_reset_history ( instance );
|
|
voclib_initialize_filterbank ( instance, 0 );
|
|
voclib_initialize_envelopes ( instance );
|
|
|
|
return 1;
|
|
}
|
|
|
|
void voclib_reset_history ( voclib_instance* instance )
|
|
{
|
|
unsigned char i;
|
|
|
|
for ( i = 0; i < instance->bands; ++i )
|
|
{
|
|
unsigned char i2;
|
|
|
|
for ( i2 = 0; i2 < instance->filters_per_band; ++i2 )
|
|
{
|
|
voclib_BiQuad_reset ( &instance->analysis_bands[i].filters[i2] );
|
|
voclib_BiQuad_reset ( &instance->synthesis_bands[i].filters[i2] );
|
|
voclib_BiQuad_reset ( &instance->synthesis_bands[i + VOCLIB_MAX_BANDS].filters[i2] );
|
|
}
|
|
voclib_envelope_reset ( &instance->analysis_envelopes[i] );
|
|
}
|
|
}
|
|
|
|
int voclib_process ( voclib_instance* instance, const float* carrier_buffer, const float* modulator_buffer, float* output_buffer, unsigned int frames )
|
|
{
|
|
unsigned int i;
|
|
const unsigned char bands = instance->bands;
|
|
const unsigned char filters_per_band = instance->filters_per_band;
|
|
|
|
if ( !carrier_buffer )
|
|
{
|
|
return 0;
|
|
}
|
|
if ( !modulator_buffer )
|
|
{
|
|
return 0;
|
|
}
|
|
if ( !output_buffer )
|
|
{
|
|
return 0;
|
|
}
|
|
if ( frames == 0 )
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
if ( instance->carrier_channels == 2 )
|
|
{
|
|
|
|
/* The carrier has two channels and the modulator has 1. */
|
|
for ( i = 0; i < frames * 2; i += 2, ++modulator_buffer )
|
|
{
|
|
unsigned char i2;
|
|
float out_left = 0.0f;
|
|
float out_right = 0.0f;
|
|
|
|
/* Run the bands in parallel and accumulate the output. */
|
|
for ( i2 = 0; i2 < bands; ++i2 )
|
|
{
|
|
unsigned char i3;
|
|
float analysis_band = voclib_BiQuad ( *modulator_buffer, &instance->analysis_bands[i2].filters[0] );
|
|
float synthesis_band_left = voclib_BiQuad ( carrier_buffer[i], &instance->synthesis_bands[i2].filters[0] );
|
|
float synthesis_band_right = voclib_BiQuad ( carrier_buffer[i + 1], &instance->synthesis_bands[i2 + VOCLIB_MAX_BANDS].filters[0] );
|
|
|
|
for ( i3 = 1; i3 < filters_per_band; ++i3 )
|
|
{
|
|
analysis_band = voclib_BiQuad ( analysis_band, &instance->analysis_bands[i2].filters[i3] );
|
|
synthesis_band_left = voclib_BiQuad ( synthesis_band_left, &instance->synthesis_bands[i2].filters[i3] );
|
|
synthesis_band_right = voclib_BiQuad ( synthesis_band_right, &instance->synthesis_bands[i2 + VOCLIB_MAX_BANDS].filters[i3] );
|
|
}
|
|
analysis_band = voclib_envelope_tick ( &instance->analysis_envelopes[i2], analysis_band );
|
|
out_left += synthesis_band_left * analysis_band;
|
|
out_right += synthesis_band_right * analysis_band;
|
|
}
|
|
output_buffer[i] = out_left;
|
|
output_buffer[i + 1] = out_right;
|
|
}
|
|
|
|
}
|
|
else
|
|
{
|
|
|
|
/* Both the carrier and the modulator have a single channel. */
|
|
for ( i = 0; i < frames; ++i )
|
|
{
|
|
unsigned char i2;
|
|
float out = 0.0f;
|
|
|
|
/* Run the bands in parallel and accumulate the output. */
|
|
for ( i2 = 0; i2 < bands; ++i2 )
|
|
{
|
|
unsigned char i3;
|
|
float analysis_band = voclib_BiQuad ( modulator_buffer[i], &instance->analysis_bands[i2].filters[0] );
|
|
float synthesis_band = voclib_BiQuad ( carrier_buffer[i], &instance->synthesis_bands[i2].filters[0] );
|
|
|
|
for ( i3 = 1; i3 < filters_per_band; ++i3 )
|
|
{
|
|
analysis_band = voclib_BiQuad ( analysis_band, &instance->analysis_bands[i2].filters[i3] );
|
|
synthesis_band = voclib_BiQuad ( synthesis_band, &instance->synthesis_bands[i2].filters[i3] );
|
|
}
|
|
analysis_band = voclib_envelope_tick ( &instance->analysis_envelopes[i2], analysis_band );
|
|
out += synthesis_band * analysis_band;
|
|
}
|
|
output_buffer[i] = out;
|
|
}
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
int voclib_set_reaction_time ( voclib_instance* instance, float reaction_time )
|
|
{
|
|
if ( reaction_time < 0.002f || reaction_time > 2.0f )
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
instance->reaction_time = reaction_time;
|
|
voclib_initialize_envelopes ( instance );
|
|
return 1;
|
|
}
|
|
|
|
float voclib_get_reaction_time ( const voclib_instance* instance )
|
|
{
|
|
return instance->reaction_time;
|
|
}
|
|
|
|
int voclib_set_formant_shift ( voclib_instance* instance, float formant_shift )
|
|
{
|
|
if ( formant_shift < 0.25f || formant_shift > 4.0f )
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
instance->formant_shift = formant_shift;
|
|
voclib_initialize_filterbank ( instance, 1 );
|
|
return 1;
|
|
}
|
|
|
|
float voclib_get_formant_shift ( const voclib_instance* instance )
|
|
{
|
|
return instance->formant_shift;
|
|
}
|
|
|
|
#endif /* VOCLIB_IMPLEMENTATION */
|
|
|
|
/* REVISION HISTORY
|
|
*
|
|
* Version 1.1 - 2019-02-16
|
|
* Breaking change: Introduced a new argument to voclib_initialize called carrier_channels. This allows the vocoder to output stereo natively.
|
|
* Better assignment of band frequencies when using lower sample rates.
|
|
* The shell now automatically normalizes the output file to match the peak amplitude in the carrier.
|
|
* Fixed a memory corruption bug in the shell which would occur in response to an error condition.
|
|
*
|
|
* Version 1.0 - 2019-01-27
|
|
* Initial release.
|
|
*/
|
|
|
|
/* LICENSE
|
|
|
|
This software is available under 2 licenses -- choose whichever you prefer.
|
|
------------------------------------------------------------------------------
|
|
ALTERNATIVE A - MIT No Attribution License
|
|
Copyright (c) 2019 Philip Bennefall
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining a copy of
|
|
this software and associated documentation files (the "Software"), to deal in
|
|
the Software without restriction, including without limitation the rights to
|
|
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
|
|
of the Software, and to permit persons to whom the Software is furnished to do
|
|
so.
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
SOFTWARE.
|
|
------------------------------------------------------------------------------
|
|
ALTERNATIVE B - Public Domain (www.unlicense.org)
|
|
This is free and unencumbered software released into the public domain.
|
|
Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
|
|
software, either in source code form or as a compiled binary, for any purpose,
|
|
commercial or non-commercial, and by any means.
|
|
|
|
In jurisdictions that recognize copyright laws, the author or authors of this
|
|
software dedicate any and all copyright interest in the software to the public
|
|
domain. We make this dedication for the benefit of the public at large and to
|
|
the detriment of our heirs and successors. We intend this dedication to be an
|
|
overt act of relinquishment in perpetuity of all present and future rights to
|
|
this software under copyright law.
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
|
|
ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
|
|
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
|
------------------------------------------------------------------------------
|
|
*/
|