+++ /dev/null
-/*
- * This source code is a product of Sun Microsystems, Inc. and is provided
- * for unrestricted use. Users may copy or modify this source code without
- * charge.
- *
- * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
- * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
- *
- * Sun source code is provided with no support and without any obligation on
- * the part of Sun Microsystems, Inc. to assist in its use, correction,
- * modification or enhancement.
- *
- * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
- * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
- * OR ANY PART THEREOF.
- *
- * In no event will Sun Microsystems, Inc. be liable for any lost revenue
- * or profits or other special, indirect and consequential damages, even if
- * Sun has been advised of the possibility of such damages.
- *
- * Sun Microsystems, Inc.
- * 2550 Garcia Avenue
- * Mountain View, California 94043
- */
-
-/*
- * g723_24.c
- *
- * Description:
- *
- * g723_24_encoder(), g723_24_decoder()
- *
- * These routines comprise an implementation of the CCITT G.723 24 Kbps
- * ADPCM coding algorithm. Essentially, this implementation is identical to
- * the bit level description except for a few deviations which take advantage
- * of workstation attributes, such as hardware 2's complement arithmetic.
- *
- */
-
-#include "g72x.h"
-#include "g72x_priv.h"
-
-/*
- * Maps G.723_24 code word to reconstructed scale factor normalized log
- * magnitude values.
- */
-static short _dqlntab[8] = {-2048, 135, 273, 373, 373, 273, 135, -2048};
-
-/* Maps G.723_24 code word to log of scale factor multiplier. */
-static short _witab[8] = {-128, 960, 4384, 18624, 18624, 4384, 960, -128};
-
-/*
- * Maps G.723_24 code words to a set of values whose long and short
- * term averages are computed and then compared to give an indication
- * how stationary (steady state) the signal is.
- */
-static short _fitab[8] = {0, 0x200, 0x400, 0xE00, 0xE00, 0x400, 0x200, 0};
-
-static short qtab_723_24[3] = {8, 218, 331};
-
-/*
- * g723_24_encoder()
- *
- * Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code.
- * Returns -1 if invalid input coding value.
- */
-int
-g723_24_encoder(
- int sl,
- G72x_STATE *state_ptr)
-{
- short sei, sezi, se, sez; /* ACCUM */
- short d; /* SUBTA */
- short y; /* MIX */
- short sr; /* ADDB */
- short dqsez; /* ADDC */
- short dq, i;
-
- /* linearize input sample to 14-bit PCM */
- sl >>= 2; /* sl of 14-bit dynamic range */
-
- sezi = predictor_zero(state_ptr);
- sez = sezi >> 1;
- sei = sezi + predictor_pole(state_ptr);
- se = sei >> 1; /* se = estimated signal */
-
- d = sl - se; /* d = estimation diff. */
-
- /* quantize prediction difference d */
- y = step_size(state_ptr); /* quantizer step size */
- i = quantize(d, y, qtab_723_24, 3); /* i = ADPCM code */
- dq = reconstruct(i & 4, _dqlntab[i], y); /* quantized diff. */
-
- sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq; /* reconstructed signal */
-
- dqsez = sr + sez - se; /* pole prediction diff. */
-
- update(3, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);
-
- return (i);
-}
-
-/*
- * g723_24_decoder()
- *
- * Decodes a 3-bit CCITT G.723_24 ADPCM code and returns
- * the resulting 16-bit linear PCM, A-law or u-law sample value.
- * -1 is returned if the output coding is unknown.
- */
-int
-g723_24_decoder(
- int i,
- G72x_STATE *state_ptr)
-{
- short sezi, sei, sez, se; /* ACCUM */
- short y; /* MIX */
- short sr; /* ADDB */
- short dq;
- short dqsez;
-
- i &= 0x07; /* mask to get proper bits */
- sezi = predictor_zero(state_ptr);
- sez = sezi >> 1;
- sei = sezi + predictor_pole(state_ptr);
- se = sei >> 1; /* se = estimated signal */
-
- y = step_size(state_ptr); /* adaptive quantizer step size */
- dq = reconstruct(i & 0x04, _dqlntab[i], y); /* unquantize pred diff */
-
- sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq); /* reconst. signal */
-
- dqsez = sr - se + sez; /* pole prediction diff. */
-
- update(3, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);
-
- return (sr << 2); /* sr was of 14-bit dynamic range */
-}
-
projects / Faustine.git / blobdiff