061991fe60
it appears a one-character typo in the cmake_minimum_required line prevents it from compiling under CMake 4.0. in order to fix that, I had to take this thing out of submodules... it is recommended to do this after you pull; git submodule deinit extern/libsndfile
140 lines
4.1 KiB
C
140 lines
4.1 KiB
C
/*
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* This source code is a product of Sun Microsystems, Inc. and is provided
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* for unrestricted use. Users may copy or modify this source code without
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* charge.
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*
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* SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
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* THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
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*
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* Sun source code is provided with no support and without any obligation on
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* the part of Sun Microsystems, Inc. to assist in its use, correction,
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* modification or enhancement.
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*
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* SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
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* INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
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* OR ANY PART THEREOF.
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*
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* In no event will Sun Microsystems, Inc. be liable for any lost revenue
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* or profits or other special, indirect and consequential damages, even if
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* Sun has been advised of the possibility of such damages.
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*
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* Sun Microsystems, Inc.
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* 2550 Garcia Avenue
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* Mountain View, California 94043
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*/
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/*
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* g723_24.c
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*
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* Description:
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*
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* g723_24_encoder (), g723_24_decoder ()
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*
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* These routines comprise an implementation of the CCITT G.723 24 Kbps
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* ADPCM coding algorithm. Essentially, this implementation is identical to
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* the bit level description except for a few deviations which take advantage
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* of workstation attributes, such as hardware 2's complement arithmetic.
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*
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*/
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#include "g72x.h"
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#include "g72x_priv.h"
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/*
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* Maps G.723_24 code word to reconstructed scale factor normalized log
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* magnitude values.
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*/
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static short _dqlntab [8] = { -2048, 135, 273, 373, 373, 273, 135, -2048 } ;
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/* Maps G.723_24 code word to log of scale factor multiplier. */
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static short _witab [8] = { -128, 960, 4384, 18624, 18624, 4384, 960, -128 } ;
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/*
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* Maps G.723_24 code words to a set of values whose long and short
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* term averages are computed and then compared to give an indication
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* how stationary (steady state) the signal is.
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*/
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static short _fitab [8] = { 0, 0x200, 0x400, 0xE00, 0xE00, 0x400, 0x200, 0 } ;
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static short qtab_723_24 [3] = { 8, 218, 331 } ;
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/*
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* g723_24_encoder ()
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*
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* Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code.
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* Returns -1 if invalid input coding value.
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*/
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int
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g723_24_encoder (
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int sl,
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G72x_STATE *state_ptr)
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{
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short sei, sezi, se, sez ; /* ACCUM */
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short d ; /* SUBTA */
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short y ; /* MIX */
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short sr ; /* ADDB */
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short dqsez ; /* ADDC */
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short dq, i ;
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/* linearize input sample to 14-bit PCM */
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sl >>= 2 ; /* sl of 14-bit dynamic range */
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sezi = predictor_zero (state_ptr) ;
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sez = sezi >> 1 ;
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sei = sezi + predictor_pole (state_ptr) ;
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se = sei >> 1 ; /* se = estimated signal */
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d = sl - se ; /* d = estimation diff. */
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/* quantize prediction difference d */
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y = step_size (state_ptr) ; /* quantizer step size */
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i = quantize (d, y, qtab_723_24, 3) ; /* i = ADPCM code */
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dq = reconstruct (i & 4, _dqlntab [i], y) ; /* quantized diff. */
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sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq ; /* reconstructed signal */
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dqsez = sr + sez - se ; /* pole prediction diff. */
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update (3, y, _witab [i], _fitab [i], dq, sr, dqsez, state_ptr) ;
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return i ;
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}
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/*
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* g723_24_decoder ()
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*
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* Decodes a 3-bit CCITT G.723_24 ADPCM code and returns
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* the resulting 16-bit linear PCM, A-law or u-law sample value.
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* -1 is returned if the output coding is unknown.
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*/
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int
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g723_24_decoder (
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int i,
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G72x_STATE *state_ptr)
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{
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short sezi, sei, sez, se ; /* ACCUM */
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short y ; /* MIX */
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short sr ; /* ADDB */
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short dq ;
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short dqsez ;
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i &= 0x07 ; /* mask to get proper bits */
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sezi = predictor_zero (state_ptr) ;
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sez = sezi >> 1 ;
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sei = sezi + predictor_pole (state_ptr) ;
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se = sei >> 1 ; /* se = estimated signal */
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y = step_size (state_ptr) ; /* adaptive quantizer step size */
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dq = reconstruct (i & 0x04, _dqlntab [i], y) ; /* unquantize pred diff */
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sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq) ; /* reconst. signal */
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dqsez = sr - se + sez ; /* pole prediction diff. */
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update (3, y, _witab [i], _fitab [i], dq, sr, dqsez, state_ptr) ;
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return arith_shift_left (sr, 2) ; /* sr was of 14-bit dynamic range */
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}
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