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µlaw audio support (from erik quanstro)

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This commit is contained in:
cinap_lenrek 2012-12-08 09:18:44 +01:00
parent 0d84343fbc
commit 7148847ff0
7 changed files with 386 additions and 4 deletions
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2
rc/bin/play
View file

@ -52,6 +52,8 @@ fn play1 {
audio/wavdec
case *flac*
audio/flacdec
case *µlaw* *audio/basic*
audio/µlawdec
case *pls*
awk 'BEGIN {FS="="} /^File/{print $2}' | play1 plain
case *

7
sys/man/1/audio
View file

@ -12,6 +12,8 @@ mp3dec, mp3enc, oggdec, oggenc, flacdec, wavdec, pcmconv \- decode and encode au
.B audio/flacdec
.br
.B audio/wavdec
.br
.B audio/µlawdec
.PP
.B audio/oggenc
.br
@ -62,12 +64,13 @@ decodes MPEG audio (layer 1, 2 and 3). The
.B -d
option enables debug output to standard error.
.I Oggdec,
.I flacdec
.I flacdec,
.I µlawdec
and
.I wavdec
are like
.I mp3dec
but decode OGG Vorbis, FLAC lossless audio and PCM Wave.
but decode OGG Vorbis, FLAC lossless audio, Sun µlaw audio and PCM Wave.
.PP
The encoders read PCM on standard input and produce compressed audio
on standard output.

2
sys/src/cmd/audio/mkfile
View file

@ -1,7 +1,7 @@
</$objtype/mkfile
LIBS=libogg libvorbis libFLAC
PROGS=pcmconv oggdec oggenc mp3dec mp3enc flacdec wavdec
PROGS=pcmconv oggdec oggenc mp3dec mp3enc flacdec wavdec µlawdec
#libs must be made first
DIRS=$LIBS $PROGS

2
sys/src/cmd/audio/pcmconv/pcmconv.c
View file

@ -249,7 +249,7 @@ main(int argc, char *argv[])
Chan ch[8];
Desc i, o;
ulong delta;
int k, r, n, m, p;
int k, r, n, m;
vlong l;
void (*oconv)(int *, uchar *, int, int, int) = nil;

8
sys/src/cmd/audio/µlawdec/mkfile Normal file
View file

@ -0,0 +1,8 @@
</$objtype/mkfile
<../config
OFILES=µlawdec.$O
TARG=µlawdec
</sys/src/cmd/mkone

368
sys/src/cmd/audio/µlawdec/µlawdec.c Normal file
View file

@ -0,0 +1,368 @@
#include <u.h>
#include <libc.h>
#include <bio.h>
enum {
Qmask = 0xf, /* quantization mask */
Nsegs = 8, /* A-law segments */
Segshift = 4,
Segmask = 0x70,
};
static short segend[Nsegs] = {
0xff, 0x1ff, 0x3ff, 0x7ff,
0xfff, 0x1fff, 0x3fff, 0x7fff
};
/* copy from CCITT G.711 specifications */
static uchar u2a[128] = { /* μ- to A-law conversions */
1, 1, 2, 2, 3, 3, 4, 4,
5, 5, 6, 6, 7, 7, 8, 8,
9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 29, 31, 33, 34, 35, 36,
37, 38, 39, 40, 41, 42, 43, 44,
46, 48, 49, 50, 51, 52, 53, 54,
55, 56, 57, 58, 59, 60, 61, 62,
64, 65, 66, 67, 68, 69, 70, 71,
72, 73, 74, 75, 76, 77, 78, 79,
81, 82, 83, 84, 85, 86, 87, 88,
89, 90, 91, 92, 93, 94, 95, 96,
97, 98, 99, 100, 101, 102, 103, 104,
105, 106, 107, 108, 109, 110, 111, 112,
113, 114, 115, 116, 117, 118, 119, 120,
121, 122, 123, 124, 125, 126, 127, 128
};
static uchar a2u[128] = { /* A- to μ-law conversions */
1, 3, 5, 7, 9, 11, 13, 15,
16, 17, 18, 19, 20, 21, 22, 23,
24, 25, 26, 27, 28, 29, 30, 31,
32, 32, 33, 33, 34, 34, 35, 35,
36, 37, 38, 39, 40, 41, 42, 43,
44, 45, 46, 47, 48, 48, 49, 49,
50, 51, 52, 53, 54, 55, 56, 57,
58, 59, 60, 61, 62, 63, 64, 64,
65, 66, 67, 68, 69, 70, 71, 72,
73, 74, 75, 76, 77, 78, 79, 79,
80, 81, 82, 83, 84, 85, 86, 87,
88, 89, 90, 91, 92, 93, 94, 95,
96, 97, 98, 99, 100, 101, 102, 103,
104, 105, 106, 107, 108, 109, 110, 111,
112, 113, 114, 115, 116, 117, 118, 119,
120, 121, 122, 123, 124, 125, 126, 127
};
/* speed doesn't matter. table has 8 entires */
static int
search(int val, short *table, int size)
{
int i;
for (i = 0; i < size; i++) {
if (val <= *table++)
return i;
}
return size;
}
/*
* linear2alaw() - Convert a 16-bit linear PCM value to 8-bit A-law
*
* linear2alaw() accepts an 16-bit integer and encodes it as A-law data.
*
* Linear Input Code Compressed Code
* ------------------------ ---------------
* 0000000wxyza 000wxyz
* 0000001wxyza 001wxyz
* 000001wxyzab 010wxyz
* 00001wxyzabc 011wxyz
* 0001wxyzabcd 100wxyz
* 001wxyzabcde 101wxyz
* 01wxyzabcdef 110wxyz
* 1wxyzabcdefg 111wxyz
*
* For further information see John C. Bellamy's Digital Telephony, 1982,
* John Wiley & Sons, pps 98-111 and 472-476.
*/
uchar
linear2alaw(int pcm) /* 2's complement (16-bit range) */
{
uchar aval;
int mask, seg;
if (pcm >= 0) {
mask = 0xd5; /* sign (7th) bit = 1 */
} else {
mask = 0x55; /* sign bit = 0 */
pcm = -pcm - 8;
}
/* Convert the scaled magnitude to segment number. */
seg = search(pcm, segend, 8);
/* Combine the sign, segment, and quantization bits. */
if (seg >= 8)
/* out of range, return maximum value. */
return 0x7f ^ mask;
else {
aval = seg << Segshift;
if (seg < 2)
aval |= pcm>>4 & Qmask;
else
aval |= pcm>>(seg + 3) & Qmask;
return aval ^ mask;
}
}
/*
* alaw2linear() - Convert an A-law value to 16-bit linear PCM
*
*/
int
alaw2linear(uchar a)
{
int t, seg;
a ^= 0x55;
t = (a & Qmask) << 4;
seg = (a & Segmask) >> Segshift;
switch (seg) {
case 0:
t += 8;
break;
case 1:
t += 0x108;
break;
default:
t += 0x108;
t <<= seg - 1;
}
return (a & 0x80) ? t : -t;
}
enum {
Bias = 0x84, /* Bias for linear code. */
};
/*
* linear2μlaw() - Convert a linear PCM value to μ-law
*
* In order to simplify the encoding process, the original linear magnitude
* is biased by adding 33 which shifts the encoding range from (0 - 8158) to
* (33 - 8191). The result can be seen in the following encoding table:
*
* Biased Linear Input Code Compressed Code
* ------------------------ ---------------
* 00000001wxyza 000wxyz
* 0000001wxyzab 001wxyz
* 000001wxyzabc 010wxyz
* 00001wxyzabcd 011wxyz
* 0001wxyzabcde 100wxyz
* 001wxyzabcdef 101wxyz
* 01wxyzabcdefg 110wxyz
* 1wxyzabcdefgh 111wxyz
*
* Each biased linear code has a leading 1 which identifies the segment
* number. The value of the segment number is equal to 7 minus the number
* of leading 0's. The quantization interval is directly available as the
* four bits wxyz. * The trailing bits (a - h) are ignored.
*
* Ordinarily the complement of the resulting code word is used for
* transmission, and so the code word is complemented before it is returned.
*
* For further information see John C. Bellamy's Digital Telephony, 1982,
* John Wiley & Sons, pps 98-111 and 472-476.
*/
uchar
linear2μlaw(int pcm)
{
int mask, seg;
uchar uval;
/* Get the sign and the magnitude of the value. */
if (pcm < 0) {
pcm = Bias - pcm;
mask = 0x7f;
} else {
pcm += Bias;
mask = 0xff;
}
/* Convert the scaled magnitude to segment number. */
seg = search(pcm, segend, 8);
/*
* Combine the sign, segment, quantization bits;
* and complement the code word.
*/
if (seg >= 8)
/* out of range, return maximum value. */
return 0x7f ^ mask;
else {
uval = seg<< 4 | ((pcm >> (seg + 3)) & 0xf);
return uval ^ mask;
}
}
/*
* μlaw2linear() - Convert a μ-law value to 16-bit linear PCM
*
* First, a biased linear code is derived from the code word. An unbiased
* output can then be obtained by subtracting 33 from the biased code.
*
* Note that this function expects to be passed the complement of the
* original code word. This is in keeping with ISDN conventions.
*/
int
μlaw2linear(uchar μ)
{
int t;
/* Complement to obtain normal μ-law value. */
μ = ~μ;
/*
* Extract and bias the quantization bits. Then
* shift up by the segment number and subtract out the bias.
*/
t = ((μ & Qmask) << 3) + Bias;
t <<= (μ & Segmask) >> Segshift;
return μ & 0x80? Bias - t: t - Bias;
}
/* A-law to μ-law conversion */
uchar
alaw2μlaw(uchar a)
{
// a &= 0xff;
if(a & 0x80)
return 0xff ^ a2u[a ^ 0xd5];
else
return 0x7f ^ a2u[a ^ 0x55];
}
/* μ-law to A-law conversion */
uchar
μlaw2alaw(uchar μ)
{
// μ &= 0xff;
if(μ & 0x80)
return 0xd5 ^ u2a[0xff ^ μ] - 1;
else
return 0x55 ^ u2a[0x7f ^ μ] - 1;
}
static void
setrate(int rate)
{
int fd;
fd = open("/dev/volume", OWRITE);
if(fd == -1){
fprint(2, "μlawdec: can't set rate %d: open: %r\n", rate);
return;
}
if(fprint(fd, "speed %d", rate) == -1)
fprint(2, "μlawdec: can't set rate %d: fprint: %r\n", rate);
else
fprint(2, "μlawdec: rate %d\n", rate);
close(fd);
}
enum {
Sig = 0,
Offset = 1,
Enc = 3,
Rate = 4,
Nchan = 5,
};
u32int
μlawword(uchar *buf, int w)
{
buf += 4*w;
return buf[0]<<24 | buf[1]<<16 | buf[2]<<8 | buf[3];
}
int
pcmconv(char *fmt)
{
int pid, pfd[2];
if(pipe(pfd) < 0)
return -1;
pid = fork();
if(pid < 0){
close(pfd[0]);
close(pfd[1]);
return -1;
}
if(pid == 0){
dup(pfd[1], 0);
close(pfd[1]);
close(pfd[0]);
execl("/bin/audio/pcmconv", "pcmconv", "-i", fmt, 0);
sysfatal("exec: %r");
}
close(pfd[1]);
return pfd[0];
}
void
main(void)
{
int fd, n;
uchar buf[5*4];
char fmt[32];
vlong off;
Biobuf i, o;
if(Binit(&i, 0, OREAD) == -1)
sysfatal("μlawdec: Binit: %r");
if(Bread(&i, buf, sizeof buf) != sizeof buf)
sysfatal("μlawdec: Bread: %r");
off = μlawword(buf, Offset);
if(off < 24)
sysfatal("μlawdec: bad offset: %lld", off);
if(μlawword(buf, Sig) != 0x2e736e64)
sysfatal("μlawdec: not .au file");
if(μlawword(buf, Enc) != 1)
sysfatal("μlawdec: not μlaw");
snprint(fmt, sizeof(fmt), "s16c1r%d", μlawword(buf, Rate));
fd = pcmconv(fmt);
if(fd < 0)
sysfatal("μlawdec: pcmconv: %r");
if(Binit(&o, fd, OWRITE) == -1)
sysfatal("μlawdec: Binit: %r");
while(off > 0){
n = sizeof(buf);
if(off < n)
n = off;
if(Bread(&i, buf, n) != n)
sysfatal("μlawdec: Bread: %r");
off -= n;
}
for(;;){
switch(Bread(&i, buf, 1)){
case 0:
goto done;
case -1:
sysfatal("μlawdec: Bread: %r");
}
n = μlaw2linear(buf[0]);
buf[0] = n&0xff;
buf[1] = (n&0xff00)>>8;
if(Bwrite(&o, buf, 2) != 2)
sysfatal("μlawdec: Bwrite: %r");
}
done:
Bterm(&o);
Bterm(&i);
}

1
sys/src/cmd/file.c
View file

@ -816,6 +816,7 @@ struct FILE_STRING
"\033Lua", "Lua bytecode", 4, OCTET,
"ID3", "mp3 audio with id3", 3, "audio/mpeg",
"OggS", "ogg audio", 4, "audio/ogg",
".snd", "µlaw audio", 4, "audio/basic",
"\211PNG", "PNG image", 4, "image/png",
"P3\n", "ppm", 3, "image/ppm",
"P6\n", "ppm", 3, "image/ppm",