+++ /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
- */
-/* 16kbps version created, used 24kbps code and changing as little as possible.
- * G.726 specs are available from ITU's gopher or WWW site (http://www.itu.ch)
- * If any errors are found, please contact me at mrand@tamu.edu
- * -Marc Randolph
- */
-
-/*
- * g723_16.c
- *
- * Description:
- *
- * g723_16_encoder(), g723_16_decoder()
- *
- * These routines comprise an implementation of the CCITT G.726 16 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_16 code word to reconstructed scale factor normalized log
- * magnitude values. Comes from Table 11/G.726
- */
-static short _dqlntab[4] = { 116, 365, 365, 116};
-
-/* Maps G.723_16 code word to log of scale factor multiplier.
- *
- * _witab[4] is actually {-22 , 439, 439, -22}, but FILTD wants it
- * as WI << 5 (multiplied by 32), so we'll do that here
- */
-static short _witab[4] = {-704, 14048, 14048, -704};
-
-/*
- * Maps G.723_16 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.
- */
-
-/* Comes from FUNCTF */
-static short _fitab[4] = {0, 0xE00, 0xE00, 0};
-
-/* Comes from quantizer decision level tables (Table 7/G.726)
- */
-static short qtab_723_16[1] = {261};
-
-
-/*
- * g723_16_encoder()
- *
- * Encodes a linear PCM, A-law or u-law input sample and returns its 2-bit code.
- * Returns -1 if invalid input coding value.
- */
-int
-g723_16_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_16, 1); /* i = ADPCM code */
-
- /* Since quantize() only produces a three level output
- * (1, 2, or 3), we must create the fourth one on our own
- */
- if (i == 3) /* i code for the zero region */
- if ((d & 0x8000) == 0) /* If d > 0, i=3 isn't right... */
- i = 0;
-
- dq = reconstruct(i & 2, _dqlntab[i], y); /* quantized diff. */
-
- sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq; /* reconstructed signal */
-
- dqsez = sr + sez - se; /* pole prediction diff. */
-
- update(2, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);
-
- return (i);
-}
-
-/*
- * g723_16_decoder()
- *
- * Decodes a 2-bit CCITT G.723_16 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_16_decoder(
- int i,
- G72x_STATE *state_ptr)
-{
- short sezi, sei, sez, se; /* ACCUM */
- short y; /* MIX */
- short sr; /* ADDB */
- short dq;
- short dqsez;
-
- i &= 0x03; /* 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 & 0x02, _dqlntab[i], y); /* unquantize pred diff */
-
- sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq); /* reconst. signal */
-
- dqsez = sr - se + sez; /* pole prediction diff. */
-
- update(2, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);
-
- /* sr was of 14-bit dynamic range */
- return (sr << 2);
-}
-
projects / Faustine.git / blobdiff