📄 sp_frm.c
字号:
/***************************************************************************
*
* File Name: sp_frm.c
*
* Purpose: Contains all functions for frame-based processing in the
* speech encoder. The frame-based processing yields the following:
* energy in the speech signal, LPC filter coefficients, perceptually-
* weighted filter coefficients (for H(z) and C(z)), perceptually-
* weighted speech, voicing level, and constrained adaptive-codebook
* (long-term predictor) choices.
*
* Below is a listing of all the functions appearing in the file.
* The functions are arranged according to their purpose. Under
* each heading, the ordering is hierarchical.
*
* High pass filtering:
* filt4_2nd()
* iir_d()
*
* AFLAT, vector quantization of LPC coefficients:
* aflat()
* aflatNewBarRecursionL()
* aflatRecursion()
* findBestInQuantList()
* getNextVec()
* initPBarVBarFullL()
* initPBarVBarL()
* setupPreQ()
* setupQuant()
*
* FLAT: derivation of the unquantized LPC coefficients:
* flat()
* cov32()
* r0Quant()
*
*
* Generation of LPC filters for each subframe:
* getSfrmLpcTx()
* compResidEnergy()
*
* Perceptual weighting:
* weightSpeechFrame()
*
* Generation of the noise weighting filter:
* getNWCoefs()
*
* Open loop lag search:
* openLoopLagSearch()
* bestDelta()
* maxCCOverGWithSign()
* getCCThreshold()
* fnExp2()
* fnLog2()
* pitchLags()
* CGInterp()
* CGInterpValid()
* findPeak()
* fnBest_CG()
* quantLag()
*
**************************************************************************/
/*_________________________________________________________________________
| |
| Include Files |
|_________________________________________________________________________|
*/
#include "mathhalf.h"
#include "mathdp31.h"
#include "sp_rom.h"
#include "sp_dec.h"
#include "sp_frm.h"
#include "sp_sfrm.h"
#include "vad.h"
#include "dtx.h"
/*_________________________________________________________________________
| |
| Local Constants |
|_________________________________________________________________________|
*/
#define ASCALE 0x0800
#define ASHIFT 4
#define CG_INT_MACS 6
#define CG_TERMS (LSMAX - LSMIN + 1)
#define CVSHIFT 2 /* Number of right shifts to be
* applied to the normalized Phi
* array in cov32, also used in flat
* to shift down normalized F, B, C
* matrices. */
#define C_FRAME_LEN (N_SUB * CG_TERMS)
#define DELTA_LEVELS 16
#define G_FRAME_LEN (LSMAX + (N_SUB-1) * S_LEN - LSMIN + 1)
#define HIGH 1
#define INV_OS_FCTR 0x1555 /* 1.0/6.0 */
#define LAG_TABLE_LEN (1 << L_BITS)
#define LMAX 142
#define LMAX_FR (LMAX * OS_FCTR)
#define LMIN 21
#define LMIN_FR (LMIN * OS_FCTR)
#define LOW 0
#define LPC_VQ_SEG 3
#define LSMAX (LMAX + CG_INT_MACS/2)
#define LSMIN (LMIN - CG_INT_MACS/2)
#define LSP_MASK 0xffff
#define L_BITS 8
#define L_ROUND (Longword)0x8000 /* Preload accumulator value for
* rounding */
#define NP_AFLAT 4
#define NUM_CLOSED 3
#define NUM_TRAJ_MAX 2
#define ONE_EIGHTH 0x1000
#define ONE_HALF 0x4000
#define ONE_QUARTER 0x2000
#define PEAK_VICINITY 3
#define PGAIN_CLAMP 0x0021 /* 0.001 */
#define PGAIN_SCALE 0x6000 /* 0.75 */
#define PW_FRAC 0x3333 /* 0.4 */
#define R0BITS 5
#define RSHIFT 2
#define S_SH 6 /* Shift offset for computing frame
* energy */
#define UV_SCALE0 -0x2976
#define UV_SCALE1 -0x46d3
#define UV_SCALE2 -0x6676
#define W_F_BUFF_LEN (F_LEN + LSMAX)
#define high(x) (shr(x,8) & 0x00ff)
#define low(x) x & 0x00ff /* This macro will return the low
* byte of a word */
#define odd(x) (x & 0x0001) /* This macro will determine if an
* integer is odd */
/*_________________________________________________________________________
| |
| State Variables (globals) |
|_________________________________________________________________________|
*/
Shortword pswAnalysisState[NP];
Shortword pswWStateNum[NP],
pswWStateDenom[NP];
/*_________________________________________________________________________
| |
| Other External Variables |
|_________________________________________________________________________|
*/
static ShortwordRom *psrTable; /* points to correct table of
* vectors */
int iLimit; /* accessible to all in this file
* and to lpcCorrQntz() in dtx.c */
static int iLow; /* the low element in this segment */
static int iThree; /* boolean, is this a three element
* vector */
static int iWordHalfPtr; /* points to the next byte */
static int iWordPtr; /* points to the next word to be
* read */
extern Shortword pswCNVSCode1[], /* comfort noise parameters */
pswCNVSCode2[],
pswCNGsp0Code[],
pswCNLpc[],
swCNR0;
/***************************************************************************
*
* FUNCTION NAME: aflat
*
* PURPOSE: Given a vector of high-pass filtered input speech samples
* (A_LEN samples), function aflat computes the NP unquantized
* reflection coefficients using the FLAT algorithm, searches
* the three segment Rc-VQ based on the AFLAT recursion, and
* outputs a quantized set of NP reflection coefficients, along
* with the three indices specifying the selected vectors
* from the Rc-VQ. The index of the quantized frame energy R0
* is also output.
*
*
* INPUT:
*
* pswSpeechToLpc[0:A_LEN-1]
* A vector of high-pass filtered input speech, from
* which the unquantized reflection coefficients and
* the index of the quantized frame energy are
* computed.
*
* OUTPUTS:
*
* piR0Index[0:0]
* An index into a 5 bit table of quantized frame
* energies.
*
* pswFinalRc[0:NP-1]
* A quantized set of NP reflection coefficients.
*
* piVQCodewds[0:2]
* An array containing the indices of the 3 reflection
* coefficient vectors selected from the three segment
* Rc-VQ.
*
* swPtch
* Flag to indicate a periodic signal component
*
* pswVadFlag
* Voice activity decision flag
* = 1: voice activity
* = 0: no voice activity
*
* pswSP
* Speech flag
* = 1: encoder generates speech frames
* = 0: encoder generate SID frames
*
*
* RETURN:
* None.
*
* REFERENCE: Sub-clauses 4.1.3, 4.1.4, and 4.1.4.1
* of GSM Recommendation 06.20
*
* KEYWORDS: AFLAT,aflat,flat,vectorquantization, reflectioncoefficients
*
*************************************************************************/
void aflat(Shortword pswSpeechToLPC[],
int piR0Index[],
Shortword pswFinalRc[],
int piVQCodewds[],
Shortword swPtch,
Shortword *pswVadFlag,
Shortword *pswSP)
{
/*_________________________________________________________________________
| |
| Automatic Variables |
|_________________________________________________________________________|
*/
Shortword pswPOldSpace[NP_AFLAT],
pswPNewSpace[NP_AFLAT],
pswVOldSpace[2 * NP_AFLAT - 1],
pswVNewSpace[2 * NP_AFLAT - 1],
*ppswPAddrs[2],
*ppswVAddrs[2],
*pswVBar,
pswPBar[NP_AFLAT],
pswVBarSpace[2 * NP_AFLAT - 1],
pswFlatsRc[NP], /* Unquantized Rc's computed by FLAT */
pswRc[NP + 1]; /* Temp list for the converted RC's */
Longword pL_CorrelSeq[NP + 1],
*pL_VBarFull,
pL_PBarFull[NP],
pL_VBarFullSpace[2 * NP - 1];
int i,
iVec,
iSeg,
iCnt; /* Loop counter */
struct QuantList quantList, /* A list of vectors */
bestPql[4]; /* The four best vectors from the
* PreQ */
struct QuantList bestQl[LPC_VQ_SEG + 1]; /* Best vectors for each of
* the three segments */
Shortword swVadScalAuto;
Shortword pswVadRc[4];
Longword pL_VadAcf[9];
Longword L_R0; /* Normalized R0 (use swRShifts to
* unnormalize). This is done prior
* to r0quant(). After this, its is
* a unnormalized number */
/*_________________________________________________________________________
| |
| Executable Code |
|_________________________________________________________________________|
*/
/* Setup pointers temporary space */
/*--------------------------------*/
pswVBar = pswVBarSpace + NP_AFLAT - 1;
pL_VBarFull = pL_VBarFullSpace + NP - 1;
ppswPAddrs[0] = pswPOldSpace;
ppswPAddrs[1] = pswPNewSpace;
ppswVAddrs[0] = pswVOldSpace + NP_AFLAT - 1;
ppswVAddrs[1] = pswVNewSpace + NP_AFLAT - 1;
/* Given the input speech, compute the optimal reflection coefficients */
/* using the FLAT algorithm. */
/*---------------------------------------------------------------------*/
L_R0 = flat(pswSpeechToLPC, pswFlatsRc, piR0Index, pL_VadAcf,
&swVadScalAuto);
/* Get unquantized reflection coefficients for VAD */ /* DTX mode */
/* algorithm */ /* DTX mode */
/* ----------------------------------------------- */ /* DTX mode */
for (i = 0; i < 4; i++) /* DTX mode */
pswVadRc[i] = pswFlatsRc[i]; /* DTX mode */
/* convert reflection coefficients to correlation */ /* DTX mode */
/* sequence */ /* DTX mode */
/* ---------------------------------------------- */ /* DTX mode */
rcToCorrDpL(ASHIFT, ASCALE, pswFlatsRc, pL_CorrelSeq); /* DTX mode */
/* Make the voice activity detection. Only swVadFlag is */ /* DTX mode */
/* modified. */ /* DTX mode */
/* ---------------------------------------------------- */ /* DTX mode */
vad_algorithm(pL_VadAcf, swVadScalAuto, pswVadRc, swPtch, /* DTX mode */
pswVadFlag);
/* if DTX mode off, then always voice activity */ /* DTX mode */
/* ------------------------------------------- */ /* DTX mode */
if (!giDTXon) *pswVadFlag = 1; /* DTX mode */
/* determination of comfort noise parameters */ /* DTX mode */
/* ----------------------------------------- */ /* DTX mode */
*pswSP = swComfortNoise(*pswVadFlag, /* DTX mode */
L_R0, /* DTX mode */
pL_CorrelSeq); /* DTX mode */
if (*pswSP == 0) /* DTX mode */
{ /* SID frame generation */ /* DTX mode */
/* use unquantized reflection coefficients in the */ /* DTX mode */
/* encoder, when SID frames are generated */ /* DTX mode */
/* ---------------------------------------------- */ /* DTX mode */
for (i = 0; i < NP; i++) /* DTX mode */
pswFinalRc[i] = pswFlatsRc[i]; /* DTX mode */
} /* DTX mode */
else /* DTX mode */
{ /* speech frame generation */
/* Set up pL_PBarFull and pL_VBarFull initial conditions, using the */
/* autocorrelation sequence derived from the optimal reflection */
/* coefficients computed by FLAT. The initial conditions are shifted */
/* right by RSHIFT bits. These initial conditions, stored as */
/* Longwords, are used to initialize PBar and VBar arrays for the */
/* next VQ segment. */
/*--------------------------------------------------------------------*/
initPBarFullVBarFullL(pL_CorrelSeq, pL_PBarFull, pL_VBarFull);
/* Set up initial PBar and VBar initial conditions, using pL_PBarFull */
/* and pL_VBarFull arrays initialized above. These are the initial */
/* PBar and VBar conditions to be used by the AFLAT recursion at the */
/* 1-st Rc-VQ segment. */
/*--------------------------------------------------------------------*/
initPBarVBarL(pL_PBarFull, pswPBar, pswVBar);
for (iSeg = 1; iSeg <= LPC_VQ_SEG; iSeg++)
{
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -