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This change set fixes bug 8126 in trunk. It is implemented via compile time options, activated via the menuselect stuff, which defaults to the old way. non-zero sample data added. Translate tables expressed in microseconds instead of milliseconds, with 5-digit data now instead of 3, giving 2 more digits of precision.

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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@80113 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Steve Murphy
2007-08-20 22:53:48 +00:00
parent c9ab65a3bf
commit 337c44236d
8 changed files with 421 additions and 55 deletions
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138
main/alaw.c
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@@ -18,7 +18,7 @@
/*! \file
*
* \brief u-Law to Signed linear conversion
* \brief a-Law to Signed linear conversion
*
* \author Mark Spencer <markster@digium.com>
*/
@@ -28,18 +28,20 @@
ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include "asterisk/alaw.h"
#include "asterisk/logger.h"
#ifndef G711_NEW_ALGORITHM
#define AMI_MASK 0x55
static inline unsigned char linear2alaw (short int linear)
static inline unsigned char linear2alaw(short int linear)
{
int mask;
int seg;
int pcm_val;
static int seg_end[8] =
{
0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF
};
{
0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF
};
pcm_val = linear;
if (pcm_val >= 0) {
@@ -50,7 +52,7 @@ static inline unsigned char linear2alaw (short int linear)
mask = AMI_MASK;
pcm_val = -pcm_val;
}
/* Convert the scaled magnitude to segment number. */
for (seg = 0; seg < 8; seg++) {
if (pcm_val <= seg_end[seg])
@@ -59,13 +61,56 @@ static inline unsigned char linear2alaw (short int linear)
/* Combine the sign, segment, and quantization bits. */
return ((seg << 4) | ((pcm_val >> ((seg) ? (seg + 3) : 4)) & 0x0F)) ^ mask;
}
/*- End of function --------------------------------------------------------*/
#else
static unsigned char linear2alaw(short sample, int full_coding)
{
static const unsigned exp_lut[128] = {
1,1,2,2,3,3,3,3,
4,4,4,4,4,4,4,4,
5,5,5,5,5,5,5,5,
5,5,5,5,5,5,5,5,
6,6,6,6,6,6,6,6,
6,6,6,6,6,6,6,6,
6,6,6,6,6,6,6,6,
6,6,6,6,6,6,6,6,
7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7 };
unsigned sign, exponent, mantissa, mag;
unsigned char alawbyte;
ast_alaw_get_sign_mag(sample, &sign, &mag);
if (mag > 32767)
mag = 32767; /* clip the magnitude for -32768 */
exponent = exp_lut[(mag >> 8) & 0x7f];
mantissa = (mag >> (exponent + 3)) & 0x0f;
if (mag < 0x100)
exponent = 0;
if (full_coding) {
/* full encoding, with sign and xform */
alawbyte = (unsigned char)(sign | (exponent << 4) | mantissa);
alawbyte ^= AST_ALAW_AMI_MASK;
} else {
/* half-cooked coding -- mantissa+exponent only (for lookup tab) */
alawbyte = (exponent << 4) | mantissa;
}
return alawbyte;
}
#endif
#ifndef G711_NEW_ALGORITHM
static inline short int alaw2linear (unsigned char alaw)
{
int i;
int seg;
alaw ^= AMI_MASK;
i = ((alaw & 0x0F) << 4);
seg = (((int) alaw & 0x70) >> 4);
@@ -73,8 +118,31 @@ static inline short int alaw2linear (unsigned char alaw)
i = (i + 0x100) << (seg - 1);
return (short int) ((alaw & 0x80) ? i : -i);
}
#else
static inline short alaw2linear(unsigned char alawbyte)
{
unsigned exponent, mantissa;
short sample;
alawbyte ^= AST_ALAW_AMI_MASK;
exponent = (alawbyte & 0x70) >> 4;
mantissa = alawbyte & 0x0f;
sample = (mantissa << 4) + 8 /* rounding error */;
if (exponent)
sample = (sample + 0x100) << (exponent - 1);
if (!(alawbyte & 0x80))
sample = -sample;
return sample;
}
#endif
#ifndef G711_NEW_ALGORITHM
unsigned char __ast_lin2a[8192];
#else
unsigned char __ast_lin2a[AST_ALAW_TAB_SIZE];
#endif
short __ast_alaw[256];
void ast_alaw_init(void)
@@ -82,14 +150,62 @@ void ast_alaw_init(void)
int i;
/*
* Set up mu-law conversion table
*/
*/
#ifndef G711_NEW_ALGORITHM
for (i = 0; i < 256; i++) {
__ast_alaw[i] = alaw2linear(i);
__ast_alaw[i] = alaw2linear(i);
}
/* set up the reverse (mu-law) conversion table */
for (i = -32768; i < 32768; i++) {
__ast_lin2a[((unsigned short)i) >> 3] = linear2alaw(i);
}
#else
for (i = 0; i < 256; i++) {
__ast_alaw[i] = alaw2linear(i);
}
/* set up the reverse (a-law) conversion table */
for (i = 0; i <= 32768; i += AST_ALAW_STEP) {
AST_LIN2A_LOOKUP(i) = linear2alaw(i, 0 /* half-cooked */);
}
#endif
#ifdef TEST_CODING_TABLES
for (i = -32768; i < 32768; ++i) {
#ifndef G711_NEW_ALGORITHM
unsigned char e1 = linear2alaw(i);
#else
unsigned char e1 = linear2alaw(i, 1);
#endif
short d1 = alaw2linear(e1);
unsigned char e2 = AST_LIN2A(i);
short d2 = alaw2linear(e2);
short d3 = AST_ALAW(e1);
if (e1 != e2 || d1 != d3 || d2 != d3) {
ast_log(LOG_WARNING, "a-Law coding tables test failed on %d: e1=%u, e2=%u, d1=%d, d2=%d\n",
i, (unsigned)e1, (unsigned)e2, (int)d1, (int)d2);
}
}
ast_log(LOG_NOTICE, "a-Law coding tables test complete.\n");
#endif /* TEST_CODING_TABLES */
#ifdef TEST_TANDEM_TRANSCODING
/* tandem transcoding test */
for (i = -32768; i < 32768; ++i) {
unsigned char e1 = AST_LIN2A(i);
short d1 = AST_ALAW(e1);
unsigned char e2 = AST_LIN2A(d1);
short d2 = AST_ALAW(e2);
unsigned char e3 = AST_LIN2A(d2);
short d3 = AST_ALAW(e3);
if (e1 != e2 || e2 != e3 || d1 != d2 || d2 != d3) {
ast_log(LOG_WARNING, "a-Law tandem transcoding test failed on %d: e1=%u, e2=%u, d1=%d, d2=%d, d3=%d\n",
i, (unsigned)e1, (unsigned)e2, (int)d1, (int)d2, (int)d3);
}
}
ast_log(LOG_NOTICE, "a-Law tandem transcoding test complete.\n");
#endif /* TEST_TANDEM_TRANSCODING */
}