decode.c

lpc10-15为美军2400bps语音压缩标准的C语音源代码。

/*

$Log: decode.c,v $
 * Revision 1.2  1996/08/20  20:22:39  jaf
 * Removed all static local variables that were SAVE'd in the Fortran
 * code, and put them in struct lpc10_decoder_state that is passed as an
 * argument.
 *
 * Removed init function, since all initialization is now done in
 * init_lpc10_decoder_state().
 *
 * Revision 1.1  1996/08/19  22:32:38  jaf
 * Initial revision
 *

*/

#ifdef P_R_O_T_O_T_Y_P_E_S
extern int decode_(integer *ipitv, integer *irms, integer *irc, integer *voice, integer *pitch, real *rms, real *rc, struct lpc10_decoder_state *st);
/* comlen contrl_ 12 */
/*:ref: ham84_ 14 3 4 4 4 */
/*:ref: median_ 4 3 4 4 4 */
#endif

/*  -- translated by f2c (version 19951025).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
*/

#include "f2c.h"

/* Common Block Declarations */

extern struct {
    integer order, lframe;
    logical corrp;
} contrl_;

#define contrl_1 contrl_

/* Table of constant values */

static integer c__2 = 2;

/* ***************************************************************** */

/* 	DECODE Version 54 */

/* $Log: decode.c,v $
 * Revision 1.2  1996/08/20  20:22:39  jaf
 * Removed all static local variables that were SAVE'd in the Fortran
 * code, and put them in struct lpc10_decoder_state that is passed as an
 * argument.
 *
 * Removed init function, since all initialization is now done in
 * init_lpc10_decoder_state().
 *
 * Revision 1.1  1996/08/19  22:32:38  jaf
 * Initial revision
 * */
/* Revision 1.5  1996/05/23  20:06:03  jaf */
/* Assigned PITCH a "default" value on the first call, since otherwise it */
/* would be left uninitialized. */

/* Revision 1.4  1996/03/26  19:35:18  jaf */
/* Commented out trace statements. */

/* Revision 1.3  1996/03/21  21:10:50  jaf */
/* Added entry INITDECODE to reinitialize the local state of subroutine */
/* DECODE. */

/* Revision 1.2  1996/03/21  21:04:50  jaf */
/* Determined which local variables should be saved from one invocation */
/* to the next, and guessed initial values for some that should have been */
/* saved, but weren't given initial values.  Many of the arrays are */
/* "constants", and many local variables are only used if the "global" */
/* variable CORRP is .TRUE. */

/* Added comments explaining which indices of array arguments are read or */
/* written. */

/* Revision 1.1  1996/02/12 03:21:10  jaf */
/* Initial revision */


/* ***************************************************************** */

/*   This subroutine provides error correction and decoding */
/*   for all LPC parameters */

/* Input: */
/*  IPITV  - Index value of pitch */
/*  IRMS   - Coded Energy */
/*  CORRP  - Error correction: */
/*    If FALSE, parameters are decoded directly with no delay.  If TRUE, */
/*    most important parameter bits are protected by Hamming code and */
/*    median smoothed.  This requires an additional frame of delay. */
/* Input/Output: */
/*  IRC    - Coded Reflection Coefficients */
/*           Indices 1 through ORDER always read, then written. */
/* Output: */
/*  VOICE  - Half frame voicing decisions */
/*           Indices 1 through 2 written. */
/*  PITCH  - Decoded pitch */
/*  RMS    - Energy */
/*  RC     - Reflection coefficients */
/*           Indices 1 through ORDER written. */

/*  NOTE: Zero RC's should be done more directly, but this would affect */
/*   coded parameter printout. */

/* This subroutine maintains local state from one call to the next.  If */
/* you want to switch to using a new audio stream for this filter, or */
/* reinitialize its state for any other reason, call the ENTRY */
/* INITDECODE. */

/* Subroutine */ int decode_(integer *ipitv, integer *irms, 
	integer *irc, integer *voice, integer *pitch, real *rms, real *rc,
			     struct lpc10_decoder_state *st)
{
    /* Initialized data */

    logical *first;
    static integer ethrs = 2048;
    static integer ethrs1 = 128;
    static integer ethrs2 = 1024;
    static integer ethrs3 = 2048;
    static integer ivtab[32] = { 24960,24960,24960,24960,25480,25480,25483,
	    25480,16640,1560,1560,1560,16640,1816,1563,1560,24960,24960,24859,
	    24856,26001,25881,25915,25913,1560,1560,7800,3640,1561,1561,3643,
	    3641 };
    static real corth[32]	/* was [4][8] */ = { 32767.f,10.f,5.f,0.f,
	    32767.f,8.f,4.f,0.f,32.f,6.4f,3.2f,0.f,32.f,6.4f,3.2f,0.f,32.f,
	    11.2f,6.4f,0.f,32.f,11.2f,6.4f,0.f,16.f,5.6f,3.2f,0.f,16.f,5.6f,
	    3.2f,0.f };
    static integer detau[128] = { 0,0,0,3,0,3,3,31,0,3,3,21,3,3,29,30,0,3,3,
	    20,3,25,27,26,3,23,58,22,3,24,28,3,0,3,3,3,3,39,33,32,3,37,35,36,
	    3,38,34,3,3,42,46,44,50,40,48,3,54,3,56,3,52,3,3,1,0,3,3,108,3,78,
	    100,104,3,84,92,88,156,80,96,3,3,74,70,72,66,76,68,3,62,3,60,3,64,
	    3,3,1,3,116,132,112,148,152,3,3,140,3,136,3,144,3,3,1,124,120,128,
	    3,3,3,3,1,3,3,3,1,3,1,1,1 };
    static integer rmst[64] = { 1024,936,856,784,718,656,600,550,502,460,420,
	    384,352,328,294,270,246,226,206,188,172,158,144,132,120,110,102,
	    92,84,78,70,64,60,54,50,46,42,38,34,32,30,26,24,22,20,18,17,16,15,
	    14,13,12,11,10,9,8,7,6,5,4,3,2,1,0 };
    static integer detab7[32] = { 4,11,18,25,32,39,46,53,60,66,72,77,82,87,92,
	    96,101,104,108,111,114,115,117,119,121,122,123,124,125,126,127,
	    127 };
    static real descl[8] = { .6953f,.625f,.5781f,.5469f,.5312f,.5391f,.4688f,
	    .3828f };
    integer *ivp2h;
    static integer deadd[8] = { 1152,-2816,-1536,-3584,-1280,-2432,768,-1920 }
	    ;
    static integer qb[8] = { 511,511,1023,1023,1023,1023,2047,4095 };
    static integer nbit[10] = { 8,8,5,5,4,4,4,4,3,2 };
    static integer zrc[10] = { 0,0,0,0,0,3,0,2,0,0 };
    static integer bit[5] = { 2,4,8,16,32 };
    integer *iovoic;
    integer *iavgp;
    integer *iptold;
    integer *erate;
    integer *drc;
    integer *dpit;
    integer *drms;

    /* System generated locals */
    integer i__1, i__2;

    /* Builtin functions */
    integer pow_ii(integer *, integer *);

    /* Local variables */
    extern /* Subroutine */ int ham84_(integer *, integer *, integer *);
    integer ipit, iout, i__, icorf, index, ivoic, ixcor, i1, i2, i4;
    extern integer median_(integer *, integer *, integer *);
    integer ishift, errcnt, lsb;

/* $Log: decode.c,v $
 * Revision 1.2  1996/08/20  20:22:39  jaf
 * Removed all static local variables that were SAVE'd in the Fortran
 * code, and put them in struct lpc10_decoder_state that is passed as an
 * argument.
 *
 * Removed init function, since all initialization is now done in
 * init_lpc10_decoder_state().
 *
 * Revision 1.1  1996/08/19  22:32:38  jaf
 * Initial revision
 * */
/* Revision 1.3  1996/03/29  22:03:47  jaf */
/* Removed definitions for any constants that were no longer used. */

/* Revision 1.2  1996/03/26  19:34:33  jaf */
/* Added comments indicating which constants are not needed in an */
/* application that uses the LPC-10 coder. */

/* Revision 1.1  1996/02/07  14:43:51  jaf */
/* Initial revision */

/*   LPC Configuration parameters: */
/* Frame size, Prediction order, Pitch period */
/*       Arguments */
/* $Log: decode.c,v $
 * Revision 1.2  1996/08/20  20:22:39  jaf
 * Removed all static local variables that were SAVE'd in the Fortran
 * code, and put them in struct lpc10_decoder_state that is passed as an
 * argument.
 *
 * Removed init function, since all initialization is now done in
 * init_lpc10_decoder_state().
 *
 * Revision 1.1  1996/08/19  22:32:38  jaf
 * Initial revision
 * */
/* Revision 1.3  1996/03/29  22:05:55  jaf */
/* Commented out the common block variables that are not needed by the */
/* embedded version. */

/* Revision 1.2  1996/03/26  19:34:50  jaf */
/* Added comments indicating which constants are not needed in an */
/* application that uses the LPC-10 coder. */

/* Revision 1.1  1996/02/07  14:44:09  jaf */
/* Initial revision */

/*   LPC Processing control variables: */

/* *** Read-only: initialized in setup */

/*  Files for Speech, Parameter, and Bitstream Input & Output, */
/*    and message and debug outputs. */

/* Here are the only files which use these variables: */

/* lpcsim.f setup.f trans.f error.f vqsetup.f */

/* Many files which use fdebug are not listed, since it is only used in */
/* those other files conditionally, to print trace statements. */
/* 	integer fsi, fso, fpi, fpo, fbi, fbo, pbin, fmsg, fdebug */
/*  LPC order, Frame size, Quantization rate, Bits per frame, */
/*    Error correction */
/* Subroutine SETUP is the only place where order is assigned a value, */
/* and that value is 10.  It could increase efficiency 1% or so to */
/* declare order as a constant (i.e., a Fortran PARAMETER) instead of as 
*/
/* a variable in a COMMON block, since it is used in many places in the */
/* core of the coding and decoding routines.  Actually, I take that back. 
*/
/* At least when compiling with f2c, the upper bound of DO loops is */
/* stored in a local variable before the DO loop begins, and then that is 
*/
/* compared against on each iteration. */
/* Similarly for lframe, which is given a value of MAXFRM in SETUP. */
/* Similarly for quant, which is given a value of 2400 in SETUP.  quant */
/* is used in only a few places, and never in the core coding and */
/* decoding routines, so it could be eliminated entirely. */
/* nbits is similar to quant, and is given a value of 54 in SETUP. */
/* corrp is given a value of .TRUE. in SETUP, and is only used in the */
/* subroutines ENCODE and DECODE.  It doesn't affect the speed of the */
/* coder significantly whether it is .TRUE. or .FALSE., or whether it is 
*/
/* a constant or a variable, since it is only examined once per frame. */
/* Leaving it as a variable that is set to .TRUE.  seems like a good */
/* idea, since it does enable some error-correction capability for */
/* unvoiced frames, with no change in the coding rate, and no noticeable 
*/
/* quality difference in the decoded speech. */
/* 	integer quant, nbits */
/* *** Read/write: variables for debugging, not needed for LPC algorithm 
*/

/*  Current frame, Unstable frames, Output clip count, Max onset buffer, 
*/
/*    Debug listing detail level, Line count on listing page */

/* nframe is not needed for an embedded LPC10 at all. */
/* nunsfm is initialized to 0 in SETUP, and incremented in subroutine */
/* ERROR, which is only called from RCCHK.  When LPC10 is embedded into */
/* an application, I would recommend removing the call to ERROR in RCCHK, 
*/
/* and remove ERROR and nunsfm completely. */
/* iclip is initialized to 0 in SETUP, and incremented in entry SWRITE in 
*/