ref: 2010240ce3c22f65d1379ec785f754253e9759b9
dir: /src/avg.c/
/*
* July 5, 1991
* Copyright 1991 Lance Norskog And Sundry Contributors
* This source code is freely redistributable and may be used for
* any purpose. This copyright notice must be maintained.
* Lance Norskog And Sundry Contributors are not responsible for
* the consequences of using this software.
*
* Channel duplication code by Graeme W. Gill - 93/5/18
* General-purpose panning by Geoffrey H. Kuenning -- 2000/11/28
*/
/*
* Sound Tools stereo/quad -> mono mixdown effect file.
* and mono/stereo -> stereo/quad channel duplication.
*
* What's in a center channel?
*/
#include "st.h"
#include <ctype.h>
#include <string.h>
/* Private data for SKEL file */
typedef struct avgstuff {
/* How to generate each output channel. sources[i][j] */
/* represents the fraction of channel i that should be passed */
/* through to channel j on output, and so forth. Channel 0 is */
/* left front, channel 1 is right front, and 2 and 3 are left */
/* and right rear, respectively. (GHK) */
double sources[4][4];
int num_pans;
int mix; /* How are we mixing it? */
} *avg_t;
#define MIX_CENTER 0
#define MIX_LEFT 1
#define MIX_RIGHT 2
#define MIX_FRONT 3
#define MIX_BACK 4
#define MIX_SPECIFIED 5
extern double atof();
#define CLIP_LEVEL ((double)(((unsigned)1 << 31) - 1))
/*
* Process options
*/
int st_avg_getopts(effp, n, argv)
eff_t effp;
int n;
char **argv;
{
avg_t avg = (avg_t) effp->priv;
double* pans = &avg->sources[0][0];
int i;
for (i = 0; i < 16; i++)
pans[i] = 0.0;
avg->mix = MIX_CENTER;
avg->num_pans = 0;
/* Parse parameters. Since we don't yet know the number of */
/* input and output channels, we'll record the information for */
/* later. */
if (n) {
if(!strcmp(argv[0], "-l"))
avg->mix = MIX_LEFT;
else if (!strcmp(argv[0], "-r"))
avg->mix = MIX_RIGHT;
else if (!strcmp(argv[0], "-f"))
avg->mix = MIX_FRONT;
else if (!strcmp(argv[0], "-b"))
avg->mix = MIX_BACK;
else if (argv[0][0] == '-' && !isdigit((int)argv[0][1])
&& argv[0][1] != '.') {
st_fail("Usage: avg [ -l | -r | -f | -b | n,n,n...,n ]");
return (ST_EOF);
}
else {
int commas;
char *s;
avg->mix = MIX_SPECIFIED;
pans[0] = atof(argv[0]);
for (s = argv[0], commas = 0; *s; ++s) {
if (*s == ',') {
++commas;
if (commas >= 16) {
st_fail("avg can only take up to 16 pan values");
return (ST_EOF);
}
pans[commas] = atof(s+1);
}
}
avg->num_pans = commas + 1;
}
}
else {
pans[0] = 0.5;
pans[1] = 0.5;
avg->num_pans = 2;
}
return (ST_SUCCESS);
}
/*
* Start processing
*/
int st_avg_start(effp)
eff_t effp;
{
/*
Hmmm, this is tricky. Lemme think:
channel orders are [0][0],[0][1], etc.
i.e., 0->0, 0->1, 0->2, 0->3, 1->0, 1->1, ...
trailing zeros are omitted
L/R balance is x= -1 for left only, 1 for right only
1->1 channel effects:
changing volume by x is x,0,0,0
1->2 channel effects:
duplicating everywhere is 1,1,0,0
1->4 channel effects:
duplicating everywhere is 1,1,1,1
2->1 channel effects:
left only is 1,0,0,0 0,0,0,0
right only is 0,0,0,0 1,0,0,0
left+right is 0.5,0,0,0 0.5,0,0,0
left-right is 1,0,0,0 -1,0,0,0
2->2 channel effects:
L/R balance can be done several ways. The standard stereo
way is both the easiest and the most sensible:
min(1-x,1),0,0,0 0,min(1+x,1),0,0
left to both is 1,1,0,0
right to both is 0,0,0,0 1,1,0,0
left+right to both is 0.5,0.5,0,0 0.5,0.5,0,0
left-right to both is 1,1,0,0 -1,-1,0,0
left-right to left, right-left to right is 1,-1,0,0 -1,1,0,0
2->4 channel effects:
front duplicated into rear is 1,0,1,0 0,1,0,1
front swapped into rear (why?) is 1,0,0,1 0,1,1,0
front put into rear as mono (why?) is 1,0,0.5,0.5 0,1,0.5,0.5
4->1 channel effects:
left front only is 1,0,0,0
left only is 0.5,0,0,0 0,0,0,0 0.5,0,0,0
etc.
4->2 channel effects:
merge front/back is 0.5,0,0,0 0,0.5,0,0 0.5,0,0,0 0,0.5,0,0
selections similar to above
4->4 channel effects:
left front to all is 1,1,1,1 0,0,0,0
right front to all is 0,0,0,0 1,1,1,1
left f/r to all f/r is 1,1,0,0 0,0,0,0 0,0,1,1 0,0,0,0
etc.
The interesting ones from above (deserving of abbreviations of
less than 16 numbers) are:
n->n volume change (1 number)
1->n duplication (0 numbers)
2->1 mixdown (0 or 2 numbers)
2->2 balance (1 number)
2->2 fully general mix (4 numbers)
2->4 duplication (0 numbers)
4->1 mixdown (0 or 4 numbers)
4->2 mixdown (0 or 2 numbers)
4->4 balance (1 or 2 numbers)
The above has one ambiguity: n->n volume change conflicts with
n->n balance for n != 1. In such a case, we'll prefer
balance, since there is already a volume effect in vol.c.
GHK 2000/11/28
*/
avg_t avg = (avg_t) effp->priv;
double pans[16];
int i;
int ichan, ochan;
for (i = 0; i < 16; i++)
pans[i] = ((double*)&avg->sources[0][0])[i];
ichan = effp->ininfo.channels;
ochan = effp->outinfo.channels;
if (ochan == -1) {
st_fail("Output must have known number of channels to use avg effect");
return(ST_EOF);
}
if ((ichan != 1 && ichan != 2 && ichan != 4)
|| (ochan != 1 && ochan != 2 && ochan != 4)) {
st_fail("Can't average %d channels into %d channels",
ichan, ochan);
return (ST_EOF);
}
/* Handle the special-case flags */
switch (avg->mix) {
case MIX_CENTER:
if (ichan == ochan) {
st_fail("Output must have different number of channels to use avg effect");
return(ST_EOF);
}
break; /* Code below will handle this case */
case MIX_LEFT:
if (ichan < 2) {
st_fail("Input must have at least two channels to use avg -l");
return(ST_EOF);
}
pans[0] = 1.0;
pans[1] = 0.0;
avg->num_pans = 2;
break;
case MIX_RIGHT:
if (ichan < 2) {
st_fail("Input must have at least two channels to use avg -r");
return(ST_EOF);
}
pans[0] = 0.0;
pans[1] = 1.0;
avg->num_pans = 2;
break;
case MIX_FRONT:
if (ichan < 4) {
st_fail("Input must have at four channels to use avg -f");
return(ST_EOF);
}
pans[0] = 1.0;
pans[1] = 0.0;
avg->num_pans = 2;
break;
case MIX_BACK:
if (ichan < 4) {
st_fail("Input must have at four channels to use avg -b");
return(ST_EOF);
}
pans[0] = 0.0;
pans[1] = 1.0;
avg->num_pans = 2;
break;
default:
break;
}
/* If the number of pans given is 4 or fewer, handle the special */
/* cases listed in the comments above. The code is lengthy but */
/* straightforward. */
if (avg->num_pans == 0) {
if (ichan == 1) {
avg->sources[0][0] = 1.0;
avg->sources[0][1] = 1.0;
avg->sources[0][2] = 1.0;
avg->sources[0][3] = 1.0;
}
else if (ichan == 2 && ochan == 1) {
avg->sources[0][0] = 0.5;
avg->sources[1][0] = 0.5;
}
else if (ichan == 2 && ochan == 4) {
avg->sources[0][0] = 1.0;
avg->sources[0][2] = 1.0;
avg->sources[1][1] = 1.0;
avg->sources[1][3] = 1.0;
}
else if (ichan == 4 && ochan == 1) {
avg->sources[0][0] = 0.25;
avg->sources[1][0] = 0.25;
avg->sources[2][0] = 0.25;
avg->sources[3][0] = 0.25;
}
else if (ichan == 4 && ochan == 2) {
avg->sources[0][0] = 0.5;
avg->sources[1][1] = 0.5;
avg->sources[2][0] = 0.5;
avg->sources[3][1] = 0.5;
}
else {
st_fail("You must specify at least one mix level when using avg with an unusual number of channels.");
return(ST_EOF);
}
}
else if (avg->num_pans == 1) {
/* Might be volume change or balance change */
if ((ichan == 2 || ichan == 4) && ichan == ochan) {
/* -1 is left only, 1 is right only */
if (avg->sources[0][0] <= 0.0) {
avg->sources[1][1] = pans[0] + 1.0;
if (avg->sources[1][1] < 0.0)
avg->sources[1][1] = 0.0;
avg->sources[0][0] = 1.0;
}
else {
avg->sources[0][0] = 1.0 - pans[0];
if (avg->sources[0][0] < 0.0)
avg->sources[0][0] = 0.0;
avg->sources[1][1] = 1.0;
}
if (ichan == 4) {
avg->sources[2][2] = avg->sources[0][0];
avg->sources[3][3] = avg->sources[1][1];
}
}
}
else if (avg->num_pans == 2) {
if (ichan == 2 && ochan == 1) {
avg->sources[0][0] = pans[0];
avg->sources[0][1] = 0.0;
avg->sources[1][0] = pans[1];
}
else if (ichan == 4 && ochan == 2) {
avg->sources[0][0] = pans[0];
avg->sources[0][1] = 0.0;
avg->sources[1][1] = pans[0];
avg->sources[2][0] = pans[1];
avg->sources[3][1] = pans[1];
}
else if (ichan == 4 && ochan == 4) {
/* pans[0] is front -> front, pans[1] is for back */
avg->sources[0][0] = pans[0];
avg->sources[0][1] = 0.0;
avg->sources[1][1] = pans[0];
avg->sources[2][2] = pans[1];
avg->sources[3][3] = pans[1];
}
}
else if (avg->num_pans == 4) {
if (ichan == 2 && ochan == 2) {
/* Shorthand for 2-channel case */
avg->sources[0][0] = pans[0];
avg->sources[0][1] = pans[1];
avg->sources[0][2] = 0.0;
avg->sources[0][3] = 0.0;
avg->sources[1][0] = pans[2];
avg->sources[1][1] = pans[3];
}
else if (ichan == 4 && ochan == 1) {
avg->sources[0][0] = pans[0];
avg->sources[0][1] = 0.0;
avg->sources[0][2] = 0.0;
avg->sources[0][3] = 0.0;
avg->sources[1][0] = pans[1];
avg->sources[2][0] = pans[2];
avg->sources[3][0] = pans[3];
}
}
return (ST_SUCCESS);
}
/*
* Process either isamp or osamp samples, whichever is smaller.
*/
int st_avg_flow(effp, ibuf, obuf, isamp, osamp)
eff_t effp;
LONG *ibuf, *obuf;
LONG *isamp, *osamp;
{
avg_t avg = (avg_t) effp->priv;
int len, done;
int ichan, ochan;
int i, j;
double samp;
ichan = effp->ininfo.channels;
ochan = effp->outinfo.channels;
len = *isamp / ichan;
if (len > *osamp / ochan)
len = *osamp / ochan;
for (done = 0; done < len; done++, ibuf += ichan, obuf += ochan) {
for (j = 0; j < ochan; j++) {
samp = 0.0;
for (i = 0; i < ichan; i++)
samp += ibuf[i] * avg->sources[i][j];
if (samp < -CLIP_LEVEL)
samp = -CLIP_LEVEL;
else if (samp > CLIP_LEVEL)
samp = CLIP_LEVEL;
obuf[j] = samp;
}
}
*isamp = len * ichan;
*osamp = len * ochan;
return (ST_SUCCESS);
}
/*
* Do anything required when you stop reading samples.
* Don't close input file!
*
* Should have statistics on right, left, and output amplitudes.
*/
int st_avg_stop(effp)
eff_t effp;
{
return (ST_SUCCESS); /* nothing to do */
}