ref: 52cacba37c6f3a125ef931afa4b9c2cdb7438fef
dir: /sys/src/cmd/audio/pcmconv/pcmconv.c/
#include <u.h>
#include <libc.h>
typedef struct Desc Desc;
typedef struct Chan Chan;
struct Desc
{
int rate;
int channels;
int framesz;
int abits; /* bits after input conversion */
int bits; /* bits in input stream per sample */
Rune fmt;
};
struct Chan
{
ulong ρ; /* factor */
ulong t; /* time */
ulong tΔ; /* output step */
ulong lΔ; /* filter step */
ulong le; /* filter end */
int u; /* unity scale */
int *h; /* filter coefficients */
int *hΔ; /* coefficient deltas for interpolation */
int wx; /* extra samples */
int ix; /* buffer index */
int nx; /* buffer size */
int *x; /* the buffer */
};
enum {
Nl = 8, /* 2^Nl samples per zero crossing in fir */
Nη = 8, /* phase bits for filter interpolation */
Np = Nl+Nη, /* phase bits (fract of fixed point) */
One = 1<<Np,
};
#define MAXINT ((int)(~0UL>>1))
#define MININT (MAXINT+1)
int
clip(vlong v)
{
if(v > MAXINT)
return MAXINT;
if(v < MININT)
return MININT;
return v;
}
int
chaninit(Chan *c, int irate, int orate, int count)
{
static int h[] = {
#include "fir.h"
};
static int hΔ[nelem(h)], init = 0;
int n;
c->ρ = ((uvlong)orate<<Np)/irate;
if(c->ρ == One)
goto Done;
c->tΔ = ((uvlong)irate<<Np)/orate;
c->lΔ = 1<<(Nl+Nη);
c->le = nelem(h)<<Nη;
c->wx = 1 + (c->le / c->lΔ);
c->u = 13128; /* unity scale factor for fir */
if(c->ρ < One){
c->u *= c->ρ;
c->u >>= Np;
c->lΔ *= c->ρ;
c->lΔ >>= Np;
c->wx *= c->tΔ;
c->wx >>= Np;
}
if(!init){
init = 1;
for(n=0; n<nelem(hΔ)-1; n++)
hΔ[n] = h[n+1] - h[n];
}
c->h = h;
c->hΔ = hΔ;
c->ix = c->wx;
c->t = c->ix<<Np;
c->nx = c->wx*2 + count;
c->x = sbrk(sizeof(c->x[0]) * c->nx);
count += c->nx; /* account for buffer accumulation */
Done:
return ((uvlong)count * c->ρ) >> Np;
}
int
filter(Chan *c)
{
ulong l, lΔ, le, p, i;
int *x, *h, *hΔ, a;
vlong v;
v = 0;
h = c->h;
hΔ = c->hΔ;
lΔ = c->lΔ;
le = c->le;
/* left side */
x = &c->x[c->t>>Np];
p = c->t & ((1<<Np)-1);
l = c->ρ < One ? (c->ρ * p)>>Np : p;
while(l < le){
i = l >> Nη;
a = l & ((1<<Nη)-1);
l += lΔ;
a *= hΔ[i];
a >>= Nη;
a += h[i];
v += (vlong)*(--x) * a;
}
/* right side */
x = &c->x[c->t>>Np];
p = (One - p) & ((1<<Np)-1);
l = c->ρ < One ? (c->ρ * p)>>Np : p;
if(p == 0) /* skip h[0] as it was already been summed above if p == 0 */
l += c->lΔ;
while(l < le){
i = l >> Nη;
a = l & ((1<<Nη)-1);
l += lΔ;
a *= hΔ[i];
a >>= Nη;
a += h[i];
v += (vlong)*x++ * a;
}
/* scale */
v >>= 2;
v *= c->u;
v >>= 27;
return clip(v);
}
int*
resample(Chan *c, int *x, int *y, int count)
{
ulong e;
int i, n;
if(c->ρ == One){
/* no rate conversion needed */
if(count > 0)
memmove(y, x, count*sizeof(int));
return y+count;
}
if(count == 0){
/* stuff zeros to drain last samples out */
while(c->ix < 2*c->wx)
c->x[c->ix++] = 0;
}
do {
/* fill buffer */
for(i = c->ix, n = c->nx; count > 0 && i < n; count--, i++)
c->x[i] = *x++;
c->ix = i;
/* need at least 2*wx samples in buffer for filter */
if(i < 2*c->wx)
break;
/* process buffer */
e = (i - c->wx)<<Np;
while(c->t < e){
*y++ = filter(c);
c->t += c->tΔ;
}
/* check if we'r at the end of buffer and wrap it */
e = c->t >> Np;
if(e >= (c->nx - c->wx)){
c->t -= e << Np;
c->t += c->wx << Np;
n = c->t >> Np;
n -= c->wx;
e -= c->wx;
i -= e;
if(i > 0){
memmove(c->x + n, c->x + e, i*sizeof(int));
n += i;
}
c->ix = n;
}
} while(count > 0);
return y;
}
void
dither(int *y, int ibits, int obits, int count)
{
static ulong prnd;
if(ibits >= 32 || obits >= ibits)
return;
while(count--){
prnd = (prnd*0x19660dL + 0x3c6ef35fL) & 0xffffffffL;
*y = clip((vlong)*y + ((int)prnd >> ibits));
y++;
}
}
void
mixin(int *y, int *x, int count)
{
while(count--){
*y = clip((vlong)*y + *x++);
y++;
}
}
void
siconv(int *dst, uchar *src, int bits, int skip, int count)
{
int i, v, s, b;
b = (bits+7)/8;
s = sizeof(int)*8-bits;
while(count--){
v = 0;
i = b;
switch(b){
case 4:
v = src[--i];
case 3:
v = (v<<8) | src[--i];
case 2:
v = (v<<8) | src[--i];
case 1:
v = (v<<8) | src[--i];
}
*dst++ = v << s;
src += skip;
}
}
void
Siconv(int *dst, uchar *src, int bits, int skip, int count)
{
int i, v, s, b;
b = (bits+7)/8;
s = sizeof(int)*8-bits;
while(count--){
v = 0;
i = 0;
switch(b){
case 4:
v = src[i++];
case 3:
v = (v<<8) | src[i++];
case 2:
v = (v<<8) | src[i++];
case 1:
v = (v<<8) | src[i];
}
*dst++ = v << s;
src += skip;
}
}
void
uiconv(int *dst, uchar *src, int bits, int skip, int count)
{
int i, s, b;
uint v;
b = (bits+7)/8;
s = sizeof(uint)*8-bits;
while(count--){
v = 0;
i = b;
switch(b){
case 4:
v = src[--i];
case 3:
v = (v<<8) | src[--i];
case 2:
v = (v<<8) | src[--i];
case 1:
v = (v<<8) | src[--i];
}
*dst++ = (v << s) - (~0UL>>1);
src += skip;
}
}
void
Uiconv(int *dst, uchar *src, int bits, int skip, int count)
{
int i, s, b;
uint v;
b = (bits+7)/8;
s = sizeof(uint)*8-bits;
while(count--){
v = 0;
i = 0;
switch(b){
case 4:
v = src[i++];
case 3:
v = (v<<8) | src[i++];
case 2:
v = (v<<8) | src[i++];
case 1:
v = (v<<8) | src[i];
}
*dst++ = (v << s) - (~0UL>>1);
src += skip;
}
}
void
ficonv(int *dst, uchar *src, int bits, int skip, int count)
{
if(bits == 32){
while(count--){
float f;
f = *((float*)src), src += skip;
if(f > 1.0)
*dst++ = MAXINT;
else if(f < -1.0)
*dst++ = MININT;
else
*dst++ = f*((float)MAXINT);
}
} else {
while(count--){
double d;
d = *((double*)src), src += skip;
if(d > 1.0)
*dst++ = MAXINT;
else if(d < -1.0)
*dst++ = MININT;
else
*dst++ = d*((float)MAXINT);
}
}
}
void
aiconv(int *dst, uchar *src, int, int skip, int count)
{
int t, seg;
uchar a;
while(count--){
a = *src, src += skip;
a ^= 0x55;
t = (a & 0xf) << 4;
seg = (a & 0x70) >> 4;
switch(seg){
case 0:
t += 8;
break;
case 1:
t += 0x108;
break;
default:
t += 0x108;
t <<= seg - 1;
}
t = (a & 0x80) ? t : -t;
*dst++ = t << (sizeof(int)*8 - 16);
}
}
void
µiconv(int *dst, uchar *src, int, int skip, int count)
{
int t;
uchar u;
while(count--){
u = *src, src += skip;
u = ~u;
t = ((u & 0xf) << 3) + 0x84;
t <<= (u & 0x70) >> 4;
t = u & 0x80 ? 0x84 - t: t - 0x84;
*dst++ = t << (sizeof(int)*8 - 16);
}
}
void
soconv(int *src, uchar *dst, int bits, int skip, int count)
{
int i, v, s, b;
b = (bits+7)/8;
s = sizeof(int)*8-bits;
while(count--){
v = *src++ >> s;
i = 0;
switch(b){
case 4:
dst[i++] = v, v >>= 8;
case 3:
dst[i++] = v, v >>= 8;
case 2:
dst[i++] = v, v >>= 8;
case 1:
dst[i] = v;
}
dst += skip;
}
}
void
Soconv(int *src, uchar *dst, int bits, int skip, int count)
{
int i, v, s, b;
b = (bits+7)/8;
s = sizeof(int)*8-bits;
while(count--){
v = *src++ >> s;
i = b;
switch(b){
case 4:
dst[--i] = v, v >>= 8;
case 3:
dst[--i] = v, v >>= 8;
case 2:
dst[--i] = v, v >>= 8;
case 1:
dst[--i] = v;
}
dst += skip;
}
}
void
uoconv(int *src, uchar *dst, int bits, int skip, int count)
{
int i, s, b;
uint v;
b = (bits+7)/8;
s = sizeof(uint)*8-bits;
while(count--){
v = ((~0UL>>1) + *src++) >> s;
i = 0;
switch(b){
case 4:
dst[i++] = v, v >>= 8;
case 3:
dst[i++] = v, v >>= 8;
case 2:
dst[i++] = v, v >>= 8;
case 1:
dst[i] = v;
}
dst += skip;
}
}
void
Uoconv(int *src, uchar *dst, int bits, int skip, int count)
{
int i, s, b;
uint v;
b = (bits+7)/8;
s = sizeof(uint)*8-bits;
while(count--){
v = ((~0UL>>1) + *src++) >> s;
i = b;
switch(b){
case 4:
dst[--i] = v, v >>= 8;
case 3:
dst[--i] = v, v >>= 8;
case 2:
dst[--i] = v, v >>= 8;
case 1:
dst[--i] = v;
}
dst += skip;
}
}
void
foconv(int *src, uchar *dst, int bits, int skip, int count)
{
if(bits == 32){
while(count--){
*((float*)dst) = *src++ / ((float)MAXINT);
dst += skip;
}
} else {
while(count--){
*((double*)dst) = *src++ / ((double)MAXINT);
dst += skip;
}
}
}
Desc
mkdesc(char *f)
{
Desc d;
Rune r;
char *p;
memset(&d, 0, sizeof(d));
p = f;
while(*p != 0){
p += chartorune(&r, p);
switch(r){
case L'r':
d.rate = strtol(p, &p, 10);
break;
case L'c':
d.channels = strtol(p, &p, 10);
break;
case L'm':
r = L'µ';
case L's':
case L'S':
case L'u':
case L'U':
case L'f':
case L'a':
case L'µ':
d.fmt = r;
d.bits = d.abits = strtol(p, &p, 10);
break;
default:
goto Bad;
}
}
if(d.rate <= 0)
goto Bad;
if(d.fmt == L'a' || d.fmt == L'µ'){
if(d.bits != 8)
goto Bad;
d.abits = 16;
} else if(d.fmt == L'f'){
if(d.bits != 32 && d.bits != 64)
goto Bad;
d.abits = sizeof(int)*8;
} else if(d.bits <= 0 || d.bits > 32)
goto Bad;
d.framesz = ((d.bits+7)/8) * d.channels;
if(d.framesz <= 0)
goto Bad;
return d;
Bad:
sysfatal("bad format: %s", f);
return d;
}
int
cread(int fd, uchar *buf, int len, int mod)
{
uchar *off = buf;
len -= (len % mod);
Again:
len = read(fd, off, len);
if(len <= 0)
return len;
off += len;
len = off - buf;
if((len % mod) != 0){
len = mod - (len % mod);
goto Again;
}
return len;
}
void
usage(void)
{
fprint(2, "usage: %s [-i fmt] [-o fmt] [-l length]\n", argv0);
exits("usage");
}
void
main(int argc, char *argv[])
{
uchar ibuf[8*1024], *obuf;
int *out, *in;
Chan ch[8];
Desc i, o;
int k, n, m, nin, nout;
vlong l;
void (*oconv)(int *, uchar *, int, int, int) = nil;
void (*iconv)(int *, uchar *, int, int, int) = nil;
o = mkdesc("s16c2r44100");
i = o;
l = -1LL;
ARGBEGIN {
case 'i':
i = mkdesc(EARGF(usage()));
break;
case 'o':
o = mkdesc(EARGF(usage()));
break;
case 'l':
l = atoll(EARGF(usage()));
break;
default:
usage();
} ARGEND;
/* check if same format */
if(i.rate == o.rate
&& i.bits == o.bits
&& i.channels == o.channels
&& i.framesz == o.framesz
&& i.fmt == o.fmt){
while((n = read(0, ibuf, sizeof(ibuf))) > 0){
if(write(1, ibuf, n) != n)
sysfatal("write: %r");
}
if(n < 0)
sysfatal("read: %r");
exits(0);
}
if(i.channels > nelem(ch))
sysfatal("too many input channels: %d", i.channels);
switch(i.fmt){
case L's': iconv = siconv; break;
case L'S': iconv = Siconv; break;
case L'u': iconv = uiconv; break;
case L'U': iconv = Uiconv; break;
case L'f': iconv = ficonv; break;
case L'a': iconv = aiconv; break;
case L'µ': iconv = µiconv; break;
default:
sysfatal("unsupported input format: %C", i.fmt);
}
switch(o.fmt){
case L's': oconv = soconv; break;
case L'S': oconv = Soconv; break;
case L'u': oconv = uoconv; break;
case L'U': oconv = Uoconv; break;
case L'f': oconv = foconv; break;
default:
sysfatal("unsupported output format: %C", o.fmt);
}
if(i.fmt == L'f' || o.fmt == L'f')
setfcr(getfcr() & ~(FPINVAL|FPOVFL));
nin = (sizeof(ibuf)-i.framesz)/i.framesz;
in = sbrk(sizeof(int) * nin);
nout = 0;
memset(ch, 0, sizeof(ch));
for(k=0; k < i.channels; k++)
nout = chaninit(&ch[k], i.rate, o.rate, nin);
/* out is also used for mixing before resampling, so needs to be max(nin, nout) */
out = sbrk(sizeof(int) * (nout>nin? nout: nin));
obuf = sbrk(o.framesz * nout);
for(;;){
n = nin * i.framesz;
if(l >= 0 && l < n)
n = l;
n = cread(0, ibuf, n, i.framesz);
if(n < 0)
sysfatal("read: %r");
if(l > 0)
l -= n;
n /= i.framesz;
(*iconv)(in, ibuf, i.bits, i.framesz, n);
if(i.channels > o.channels){
for(k=1; k<i.channels; k++){
(*iconv)(out, ibuf + k*((i.bits+7)/8), i.bits, i.framesz, n);
mixin(in, out, n);
}
}
dither(in, i.abits, o.abits, n);
m = resample(&ch[0], in, out, n) - out;
if(m < 1){
if(n == 0)
break;
} else
(*oconv)(out, obuf, o.bits, o.framesz, m);
if(i.channels == o.channels){
for(k=1; k<i.channels; k++){
(*iconv)(in, ibuf + k*((i.bits+7)/8), i.bits, i.framesz, n);
dither(in, i.abits, o.abits, n);
resample(&ch[k], in, out, n);
if(m > 0)
(*oconv)(out, obuf + k*((o.bits+7)/8), o.bits, o.framesz, m);
}
} else if(m > 0){
for(k=1; k<o.channels; k++)
(*oconv)(out, obuf + k*((o.bits+7)/8), o.bits, o.framesz, m);
}
if(m > 0){
m *= o.framesz;
if(write(1, obuf, m) != m)
sysfatal("write: %r");
}
if(n == 0)
break;
}
exits(0);
}