ref: 3d55a193330e1da375d33d394275e56602e67d7e
dir: /lpc10/lpcdec.c/
/*
* Revision 1.2 1996/08/20 20:30:11 jaf
* Removed all static local variables that were SAVE'd in the Fortran
* code, and put them in struct lpc10_encoder_state that is passed as an
* argument.
*
* Removed init function, since all initialization is now done in
* init_lpc10_encoder_state().
*
* Changed name of function from lpcenc_ to lpc10_encode, simply to make
* all lpc10 functions have more consistent naming with each other.
*
* Revision 1.1 1996/08/19 22:31:48 jaf
* Initial revision
*
*/
/* -- translated by f2c (version 19951025).
You must link the resulting object file with the libraries:
-lf2c -lm (in that order)
*/
#include "f2c.h"
extern int lpcdec_(integer *bits, real *speech);
extern int initlpcdec_(void);
/* Common Block Declarations */
extern struct {
integer order, lframe;
logical corrp;
} contrl_;
#define contrl_1 contrl_
/* Table of constant values */
static integer c__10 = 10;
/* ***************************************************************** */
/*
* Revision 1.2 1996/08/20 20:30:11 jaf
* Removed all static local variables that were SAVE'd in the Fortran
* code, and put them in struct lpc10_encoder_state that is passed as an
* argument.
*
* Removed init function, since all initialization is now done in
* init_lpc10_encoder_state().
*
* Changed name of function from lpcenc_ to lpc10_encode, simply to make
* all lpc10 functions have more consistent naming with each other.
*
* Revision 1.1 1996/08/19 22:31:48 jaf
* Initial revision
* */
/* Revision 1.1 1996/03/28 00:03:00 jaf */
/* Initial revision */
/* ***************************************************************** */
/* Decode 54 bits to one frame of 180 speech samples. */
/* Input: */
/* BITS - 54 encoded bits, stored 1 per array element. */
/* Indices 1 through 53 read (SYNC bit ignored). */
/* Output: */
/* SPEECH - Speech encoded as real values in the range [-1,+1]. */
/* Indices 1 through 180 written. */
/* 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 */
/* INITLPCDEC. */
/* Subroutine */ int lpc10_decode(integer *bits, real *speech,
struct lpc10_decoder_state *st)
{
integer irms, voice[2], pitch, ipitv;
extern /* Subroutine */ int decode_(integer *, integer *, integer *,
integer *, integer *, real *, real *, struct lpc10_decoder_state *);
real rc[10];
extern /* Subroutine */ int chanrd_(integer *, integer *, integer *,
integer *, integer *), synths_(integer *,
integer *, real *, real *, real *, integer *,
struct lpc10_decoder_state *);
integer irc[10], len;
real rms;
/* LPC Configuration parameters: */
/* Frame size, Prediction order, Pitch period */
/* Arguments */
/* 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
*/
/* sread.f. When LPC10 is embedded into an application, one might want */
/* to cause it to be incremented in a routine that takes the output of */
/* SYNTHS and sends it to an audio device. It could be optionally */
/* displayed, for those that might want to know what it is. */
/* maxosp is never initialized to 0 in SETUP, although it probably should
*/
/* be, and it is updated in subroutine ANALYS. I doubt that its value */
/* would be of much interest to an application in which LPC10 is */
/* embedded. */
/* listl and lincnt are not needed for an embedded LPC10 at all. */
/* integer nframe, nunsfm, iclip, maxosp, listl, lincnt */
/* common /contrl/ fsi, fso, fpi, fpo, fbi, fbo, pbin, fmsg, fdebug */
/* common /contrl/ quant, nbits */
/* common /contrl/ nframe, nunsfm, iclip, maxosp, listl, lincnt */
/* Local variables that need not be saved */
/* Uncoded speech parameters */
/* Coded speech parameters */
/* Others */
/* Local state */
/* None */
/* Parameter adjustments */
if (bits) {
--bits;
}
if (speech) {
--speech;
}
/* Function Body */
chanrd_(&c__10, &ipitv, &irms, irc, &bits[1]);
decode_(&ipitv, &irms, irc, voice, &pitch, &rms, rc, st);
synths_(voice, &pitch, &rms, rc, &speech[1], &len, st);
return 0;
} /* lpcdec_ */