151 lines
5.7 KiB
C
151 lines
5.7 KiB
C
/*
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* FILE: resample.h
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* BY: Julius Smith (at CCRMA, Stanford U)
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* C BY: translated from SAIL to C by Christopher Lee Fraley
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* (cf0v@andrew.cmu.edu)
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* DATE: 7-JUN-88
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* VERS: 2.0 (17-JUN-88, 3:00pm)
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*/
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/*
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* October 29, 1999
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* Various changes, bugfixes(?), increased precision, by Stan Brooks.
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*
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* This source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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*
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*/
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/* Conversion constants */
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#define Lc 7
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#define Nc (1<<Lc)
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#define La 16
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#define Na (1<<La)
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#define Lp (Lc+La)
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#define Np (1<<Lp)
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#define Amask (Na-1)
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#define Pmask (Np-1)
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#define MAXNWING (80<<Lc)
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/* Description of constants:
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*
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* Nc - is the number of look-up values available for the lowpass filter
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* between the beginning of its impulse response and the "cutoff time"
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* of the filter. The cutoff time is defined as the reciprocal of the
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* lowpass-filter cut off frequence in Hz. For example, if the
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* lowpass filter were a sinc function, Nc would be the index of the
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* impulse-response lookup-table corresponding to the first zero-
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* crossing of the sinc function. (The inverse first zero-crossing
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* time of a sinc function equals its nominal cutoff frequency in Hz.)
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* Nc must be a power of 2 due to the details of the current
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* implementation. The default value of 128 is sufficiently high that
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* using linear interpolation to fill in between the table entries
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* gives approximately 16-bit precision, and quadratic interpolation
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* gives about 23-bit (float) precision in filter coefficients.
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*
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* Lc - is log base 2 of Nc.
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*
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* La - is the number of bits devoted to linear interpolation of the
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* filter coefficients.
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*
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* Lp - is La + Lc, the number of bits to the right of the binary point
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* in the integer "time" variable. To the left of the point, it indexes
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* the input array (X), and to the right, it is interpreted as a number
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* between 0 and 1 sample of the input X. The default value of 23 is
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* about right. There is a constraint that the filter window must be
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* "addressable" in a int32_t, more precisely, if Nmult is the number
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* of sinc zero-crossings in the right wing of the filter window, then
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* (Nwing<<Lp) must be expressible in 31 bits.
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*
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*/
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/* this Float MUST match that in filter.c */
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#define Float double/*float*/
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#define ISCALE 0x10000
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/* largest factor for which exact-coefficients upsampling will be used
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* */
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#define NQMAX 511
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#define BUFFSIZE 8192 /*16384*/ /* Total I/O buffer size */
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typedef short st_sample_t;
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typedef unsigned long st_size_t;
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typedef int st_ssize_t;
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#define ST_SAMPLE_MAX 0x7fff
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#define ST_SAMPLE_MIN (-ST_SAMPLE_MAX - 1)
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#define ST_SUCCESS 0
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#define ST_EOF 1
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#define ST_SAMPLE_RATE 8000
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#define ST_CHANNELS 1
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/* Private data for Lerp via LCM file */
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typedef struct resamplestuff {
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double Factor; /* Factor = Fout/Fin sample rates */
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double rolloff; /* roll-off frequency */
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double beta; /* passband/stopband tuning magic */
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int quadr; /* non-zero to use qprodUD quadratic interpolation */
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long Nmult;
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long Nwing;
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long Nq;
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Float *Imp; /* impulse [Nwing+1] Filter coefficients */
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double Time; /* Current time/pos in input sample */
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long dhb;
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long a,b; /* gcd-reduced input,output rates */
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long t; /* Current time/pos for exact-coeff's method */
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long Xh; /* number of past/future samples needed by filter */
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long Xoff; /* Xh plus some room for creep */
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long Xread; /* X[Xread] is start-position to enter new samples */
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long Xp; /* X[Xp] is position to start filter application */
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long Xsize,Ysize; /* size (Floats) of X[],Y[] */
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Float *X, *Y; /* I/O buffers */
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} *resample_t;
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typedef struct compand {
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int expectedChannels; /* Also flags that channels aren't to be treated
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individually when = 1 and input not mono */
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int transferPoints; /* Number of points specified on the transfer
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function */
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double *attackRate; /* An array of attack rates */
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double *decayRate; /* ... and of decay rates */
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double *transferIns; /* ... and points on the transfer function */
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double *transferOuts;
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double *volume; /* Current "volume" of each channel */
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double outgain; /* Post processor gain */
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double delay; /* Delay to apply before companding */
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st_sample_t *delay_buf; /* Old samples, used for delay processing */
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st_ssize_t delay_buf_size;/* Size of delay_buf in samples */
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st_ssize_t delay_buf_ptr; /* Index into delay_buf */
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st_ssize_t delay_buf_cnt; /* No. of active entries in delay_buf */
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short int delay_buf_full; /* Shows buffer situation (important for st_compand_drain) */
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} *compand_t;
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int st_resample_start(resample_t *rH, int inrate, int outrate);
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int st_resample_flow(resample_t *rH, st_sample_t *ibuf, st_sample_t *obuf,
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st_size_t *isamp, st_size_t *osamp);
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int st_resample_drain(resample_t *rH, st_sample_t *obuf, st_size_t *osamp);
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int st_resample_stop(resample_t *rH);
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int st_compand_getopts(compand_t l, int n, char **argv);
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int st_compand_start(compand_t *lH, char **opts, int nopts);
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int st_compand_flow(compand_t l, st_sample_t *ibuf, st_sample_t *obuf,
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st_size_t *isamp, st_size_t *osamp);
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int st_compand_drain(compand_t l, st_sample_t *obuf, st_size_t *osamp);
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int st_compand_stop(compand_t l);
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void st_report(const char *fmt, ...);
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void st_fail(const char *fmt, ...);
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void st_warn(const char *fmt, ...);
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long st_gcd(long a, long b);
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