ref: a3f2d6d23ed1be69fee607bdedadc0438fd01305
dir: /sys/src/libpcm/conv.c/
#include <u.h>
#include <libc.h>
#include <pcm.h>
typedef struct Chan Chan;
typedef struct Pcmconv Pcmconv;
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 */
};
struct Pcmconv
{
Pcmdesc idesc;
Pcmdesc odesc;
void (*iconv)(int *, uchar *, int, int, int);
void (*oconv)(int *, uchar *, int, int, int);
int *in;
int *out;
uchar *buf;
int nbuf;
ulong prnd;
int flags;
Chan ch[];
};
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,
Fcopy = 1<<0,
Nin = 2048,
};
#define MAXINT ((int)(~0UL>>1))
#define MININT (MAXINT+1)
#define clip(v) ((v) > MAXINT ? MAXINT : ((v) < MININT ? MININT : (v)))
static int
chaninit(Chan *c, int irate, int orate, int count, uintptr caller)
{
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){
for(n=0; n<nelem(hΔ)-1; n++)
hΔ[n] = h[n+1] - h[n];
init = 1;
}
c->h = h;
c->hΔ = hΔ;
c->ix = c->wx;
c->t = c->ix<<Np;
c->nx = c->wx*2 + count;
c->x = mallocz(sizeof(c->x[0]) * c->nx, 1);
if(c->x == nil){
werrstr("memory");
return -1;
}
setmalloctag(c->x, caller);
count += c->nx; /* account for buffer accumulation */
Done:
return ((uvlong)count * c->ρ) >> Np;
}
static 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);
}
static 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;
}
static ulong
dither(int *y, int ibits, int obits, int count, ulong prnd)
{
if(ibits >= 32 || obits >= ibits)
return prnd;
while(count--){
prnd = (prnd*0x19660dL + 0x3c6ef35fL) & 0xffffffffL;
*y = clip((vlong)*y + ((int)prnd >> ibits));
y++;
}
return prnd;
}
static void
mixin(int *y, int *x, int count)
{
while(count--){
*y = clip((vlong)*y + *x++);
y++;
}
}
static 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;
}
}
static 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;
}
}
static 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;
}
}
static 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;
}
}
static 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*((double)MAXINT);
}
}
}
static 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);
}
}
static 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);
}
}
static 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;
}
}
static 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;
}
}
static 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;
}
}
static 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;
}
}
static 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;
}
}
}
Pcmconv *
allocpcmconv(Pcmdesc *i, Pcmdesc *o)
{
uintptr caller;
Pcmconv *c;
int k, nout;
if(i->channels < 1){
werrstr("invalid number of input channels: %d", i->channels);
return nil;
}
if(o->channels < 1){
werrstr("invalid number of output channels: %d", o->channels);
return nil;
}
caller = getcallerpc(&i);
c = mallocz(sizeof(*c) + i->channels*sizeof(Chan) + i->framesz, 1);
if(c == nil){
Nomem:
werrstr("memory");
goto Err;
}
setmalloctag(c, caller);
memcpy(&c->idesc, i, sizeof(*i));
memcpy(&c->odesc, o, sizeof(*o));
c->buf = (uchar*)&c->ch[i->channels+1];
switch(i->fmt){
case L's': c->iconv = siconv; break;
case L'S': c->iconv = Siconv; break;
case L'u': c->iconv = uiconv; break;
case L'U': c->iconv = Uiconv; break;
case L'f': c->iconv = ficonv; break;
case L'a': c->iconv = aiconv; break;
case L'µ': c->iconv = µiconv; break;
default:
werrstr("unsupported input format: %C", i->fmt);
goto Err;
}
switch(o->fmt){
case L's': c->oconv = soconv; break;
case L'S': c->oconv = Soconv; break;
case L'u': c->oconv = uoconv; break;
case L'U': c->oconv = Uoconv; break;
case L'f': c->oconv = foconv; break;
default:
werrstr("unsupported output format: %C", o->fmt);
goto Err;
}
/* if same format, just copy */
c->flags = (
i->rate == o->rate
&& i->bits == o->bits
&& i->channels == o->channels
&& i->framesz == o->framesz
&& i->fmt == o->fmt
) ? Fcopy : 0;
c->in = malloc(sizeof(int) * Nin);
if(c->in == nil)
goto Nomem;
setmalloctag(c->in, caller);
nout = 0;
for(k=0; k < i->channels; k++){
nout = chaninit(&c->ch[k], i->rate, o->rate, Nin, caller);
if(nout < 0)
goto Err;
}
/* out is also used for mixing before resampling, so needs to be max(Nin, nout) */
c->out = malloc(sizeof(int) * (nout > Nin ? nout : Nin));
if(c->out == nil)
goto Nomem;
setmalloctag(c->out, caller);
return c;
Err:
freepcmconv(c);
return nil;
}
void
freepcmconv(Pcmconv *c)
{
int k;
if(c == nil)
return;
free(c->in);
free(c->out);
for(k=0; k < c->idesc.channels; k++)
free(c->ch[k].x);
free(c);
}
static int
conv(Pcmconv *c, uchar *in, uchar *out0, int insz)
{
uchar *out;
Pcmdesc *i, *o;
int k, n, m, nin;
i = &c->idesc;
o = &c->odesc;
out = out0;
nin = insz / i->framesz;
for(;;){
if((n = nin) > Nin)
n = Nin;
nin -= n;
c->iconv(c->in, in, i->bits, i->framesz, n);
if(i->channels > o->channels){
for(k=1; k<i->channels; k++){
c->iconv(c->out, in + k*((i->bits+7)/8), i->bits, i->framesz, n);
mixin(c->in, c->out, n);
}
}
c->prnd = dither(c->in, i->abits, o->abits, n, c->prnd);
m = resample(&c->ch[0], c->in, c->out, n) - c->out;
if(m < 1){
if(n == 0)
break;
} else
c->oconv(c->out, out, o->bits, o->framesz, m);
if(i->channels == o->channels){
for(k=1; k<i->channels; k++){
c->iconv(c->in, in + k*((i->bits+7)/8), i->bits, i->framesz, n);
c->prnd = dither(c->in, i->abits, o->abits, n, c->prnd);
resample(&c->ch[k], c->in, c->out, n);
if(m > 0)
c->oconv(c->out, out + k*((o->bits+7)/8), o->bits, o->framesz, m);
}
} else if(m > 0){
for(k=1; k<o->channels; k++)
c->oconv(c->out, out + k*((o->bits+7)/8), o->bits, o->framesz, m);
}
if(m > 0)
out += m * o->framesz;
if(n == 0)
break;
in += n * i->framesz;
}
return out - (uchar*)out0;
}
int
pcmconv(Pcmconv *c, void *in0, void *out0, int insz)
{
uchar *in, *out;
Pcmdesc *i;
int n;
if(c->flags & Fcopy){
memmove(out0, in0, insz);
return insz;
}
i = &c->idesc;
in = in0;
out = out0;
if(c->nbuf > 0){
n = i->framesz - c->nbuf;
if(n > insz)
n = insz;
memcpy(c->buf+c->nbuf, in, n);
c->nbuf += n;
in += n;
insz -= n;
if(c->nbuf < i->framesz)
return 0;
out += conv(c, c->buf, out, i->framesz);
c->nbuf = 0;
}
n = insz % i->framesz;
insz -= n;
out += conv(c, in, out, insz);
if(n > 0){
memcpy(c->buf, in+insz, n);
c->nbuf += n;
}
return out - (uchar*)out0;
}
int
pcmratio(Pcmconv *c, int insz)
{
int outsz, fsz;
fsz = c->idesc.framesz;
if(insz < fsz)
goto Bad;
insz = (insz + fsz)/fsz;
outsz = ((uvlong)insz * c->odesc.framesz * ((uvlong)c->odesc.rate<<Np)/c->idesc.rate) >> Np;
if(outsz >= c->odesc.framesz)
return outsz;
Bad:
werrstr("invalid buffer size: %d", insz);
return -1;
}