| /*************************************************************************/ |
| /* */ |
| /* Language Technologies Institute */ |
| /* Carnegie Mellon University */ |
| /* Copyright (c) 2010 */ |
| /* All Rights Reserved. */ |
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| /* 4. The authors' names are not used to endorse or promote products */ |
| /* derived from this software without specific prior written */ |
| /* permission. */ |
| /* */ |
| /* CARNEGIE MELLON UNIVERSITY AND THE CONTRIBUTORS TO THIS WORK */ |
| /* DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING */ |
| /* ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT */ |
| /* SHALL CARNEGIE MELLON UNIVERSITY NOR THE CONTRIBUTORS BE LIABLE */ |
| /* FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES */ |
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| /* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, */ |
| /* ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF */ |
| /* THIS SOFTWARE. */ |
| /* */ |
| /*************************************************************************/ |
| /* Author: Alan W Black (awb@cs.cmu.edu) */ |
| /* Date: March 2001 */ |
| /*************************************************************************/ |
| /* */ |
| /* Minor fixes to make it properly ansi and fit into cst */ |
| /* */ |
| /*************************************************************************/ |
| /* |
| * 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" |
| |
| /* |
| * 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, |
| int in_coding, |
| struct 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; |
| |
| switch (in_coding) { /* linearize input sample to 14-bit PCM */ |
| case AUDIO_ENCODING_LINEAR: |
| sl >>= 2; /* sl of 14-bit dynamic range */ |
| break; |
| default: |
| return (-1); |
| } |
| |
| sezi = g72x_predictor_zero(state_ptr); |
| sez = sezi >> 1; |
| sei = sezi + g72x_predictor_pole(state_ptr); |
| se = sei >> 1; /* se = estimated signal */ |
| |
| d = sl - se; /* d = estimation diff. */ |
| |
| /* quantize prediction difference d */ |
| y = g72x_step_size(state_ptr); /* quantizer step size */ |
| i = g72x_quantize(d, y, qtab_723_24, 3); /* i = ADPCM code */ |
| dq = g72x_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. */ |
| |
| g72x_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, |
| int out_coding, |
| struct 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 = g72x_predictor_zero(state_ptr); |
| sez = sezi >> 1; |
| sei = sezi + g72x_predictor_pole(state_ptr); |
| se = sei >> 1; /* se = estimated signal */ |
| |
| y = g72x_step_size(state_ptr); /* adaptive quantizer step size */ |
| dq = g72x_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. */ |
| |
| g72x_update(3, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr); |
| |
| switch (out_coding) { |
| case AUDIO_ENCODING_LINEAR: |
| return (sr << 2); /* sr was of 14-bit dynamic range */ |
| default: |
| return (-1); |
| } |
| } |
