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/*
* FILE: converter.c
* PROGRAM: RAT
* AUTHOR: O.Hodson <O.Hodson@cs.ucl.ac.uk>
*
* Copyright (c) 1998-2001 University College London
* All rights reserved.
*/
#ifndef HIDE_SOURCE_STRINGS
static const char cvsid[] =
"$Id: convert_util.c,v 1.11 2001/01/08 20:30:00 ucaccsp Exp $";
#endif /* HIDE_SOURCE_STRINGS */
#include "config_unix.h"
#include "config_win32.h"
#include "audio_types.h"
#include "converter_types.h"
#include "convert_util.h"
#include "debug.h"
/* Mono-Stereo Conversion ***************************************************/
/* Note src_len is length block in number of samples */
/* i.e nChannels * nSamplingIntervals */
void
converter_change_channels (sample *src,
int src_len,
int src_channels,
sample *dst,
int dst_len,
int dst_channels)
{
int di, si;
int t;
assert(src_channels == 1 || src_channels == 2);
assert(dst_channels == 1 || dst_channels == 2);
assert(dst_channels != src_channels);
assert(src_len/src_channels == dst_len/dst_channels);
if (src_len == 0) {
return;
}
/* Differing directions of conversions means we can do in place
* conversion if necessary.
*/
switch(src_channels) {
case 1:
di = dst_len - 1;
si = src_len - 1;
do {
dst[di--] = src[si];
dst[di--] = src[si--];
} while (si >= 0);
assert(di == si);
break;
case 2:
si = 0;
di = 0;
do {
t = src[si++];
t += src[si++];
t /= 2;
dst[di++] = t;
} while (si != src_len);
assert(di == dst_len);
break;
}
UNUSED(dst_channels);
}
int
gcd (int a, int b)
{
if (b) return gcd(b, a%b);
return a;
}
int
conversion_steps(int f1, int f2)
{
int minf, maxf, r;
minf = min(f1, f2);
maxf = max(f1, f2);
r = maxf / minf;
if (f1 == f2) {
return 0;
} else if (r * minf == maxf) {
return 1;
} else {
return 2;
}
}
int
converter_format_valid(const converter_fmt_t *cfmt)
{
if (cfmt->src_freq % 8000 &&
cfmt->src_freq % 11025) {
return FALSE;
}
if (cfmt->src_channels != 1 &&
cfmt->src_channels != 2) {
return FALSE;
}
if (cfmt->dst_freq % 8000 &&
cfmt->dst_freq % 11025) {
return FALSE;
}
if (cfmt->dst_channels != 1 &&
cfmt->dst_channels != 2) {
return FALSE;
}
return TRUE;
}
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