This is psy.c in view mode; [Download] [Up]
/**********************************************************************
Copyright (c) 1991 MPEG/audio software simulation group, All Rights Reserved
psy.c
**********************************************************************/
/**********************************************************************
* MPEG/audio coding/decoding software, work in progress *
* NOT for public distribution until verified and approved by the *
* MPEG/audio committee. For further information, please contact *
* Davis Pan, 508-493-2241, e-mail: pan@3d.enet.dec.com *
* *
* VERSION 3.9 *
* changes made since last update: *
* date programmers comment *
* 2/25/91 Davis Pan start of version 1.0 records *
* 5/10/91 W. Joseph Carter Ported to Macintosh and Unix. *
* 7/10/91 Earle Jennings Ported to MsDos. *
* replace of floats with FLOAT *
* 2/11/92 W. Joseph Carter Fixed mem_alloc() arg for "absthr". *
* 7/24/92 M. Iwadare HANN window coefficients modified. *
* 7/27/92 Masahiro Iwadare Bug fix, FFT modification for Layer 3 *
* 7/27/92 Masahiro Iwadare Bug fix, "new", "old", and "oldest" *
* updates *
* 8/07/92 Mike Coleman Bug fix, read_absthr() *
**********************************************************************/
#include "common.h"
#include "encoder.h"
void psycho_anal(buffer,savebuf,chn,lay,snr32,sfreq)
short int *buffer;
short int savebuf[1056];
int chn, lay;
FLOAT snr32[32];
double sfreq; /* to match prototype : float args are always double */
{
unsigned int i, j, k;
FLOAT r_prime, phi_prime;
FLOAT freq_mult, bval_lo, minthres, sum_energy;
double tb, temp1, temp2, temp3;
/* The static variables "r", "phi_sav", "new", "old" and "oldest" have */
/* to be remembered for the unpredictability measure. For "r" and */
/* "phi_sav", the first index from the left is the channel select and */
/* the second index is the "age" of the data. */
static int new = 0, old = 1, oldest = 0;
static int init = 0, flush, sync_flush, syncsize, sfreq_idx;
/* The following static variables are constants. */
static double nmt = 5.5;
static FLOAT crit_band[27] = {0, 100, 200, 300, 400, 510, 630, 770,
920, 1080, 1270,1480,1720,2000,2320, 2700,
3150, 3700, 4400,5300,6400,7700,9500,12000,
15500,25000,30000};
static FLOAT bmax[27] = {20.0, 20.0, 20.0, 20.0, 20.0, 17.0, 15.0,
10.0, 7.0, 4.4, 4.5, 4.5, 4.5, 4.5,
4.5, 4.5, 4.5, 4.5, 4.5, 4.5, 4.5,
4.5, 4.5, 4.5, 3.5, 3.5, 3.5};
/* The following pointer variables point to large areas of memory */
/* dynamically allocated by the mem_alloc() function. Dynamic memory */
/* allocation is used in order to avoid stack frame or data area */
/* overflow errors that otherwise would have occurred at compile time */
/* on the Macintosh computer. */
FLOAT *grouped_c, *grouped_e, *nb, *cb, *ecb, *bc;
FLOAT *wsamp_r, *wsamp_i, *phi, *energy;
FLOAT *c, *fthr;
F32 *snrtmp;
static int *numlines;
static int *partition;
static FLOAT *cbval, *rnorm;
static FLOAT *window;
static FLOAT *absthr;
static double *tmn;
static FCB *s;
static FHBLK *lthr;
static F2HBLK *r, *phi_sav;
/* These dynamic memory allocations simulate "automatic" variables */
/* placed on the stack. For each mem_alloc() call here, there must be */
/* a corresponding mem_free() call at the end of this function. */
grouped_c = (FLOAT *) mem_alloc(sizeof(FCB), "grouped_c");
grouped_e = (FLOAT *) mem_alloc(sizeof(FCB), "grouped_e");
nb = (FLOAT *) mem_alloc(sizeof(FCB), "nb");
cb = (FLOAT *) mem_alloc(sizeof(FCB), "cb");
ecb = (FLOAT *) mem_alloc(sizeof(FCB), "ecb");
bc = (FLOAT *) mem_alloc(sizeof(FCB), "bc");
wsamp_r = (FLOAT *) mem_alloc(sizeof(FBLK), "wsamp_r");
wsamp_i = (FLOAT *) mem_alloc(sizeof(FBLK), "wsamp_i");
phi = (FLOAT *) mem_alloc(sizeof(FBLK), "phi");
energy = (FLOAT *) mem_alloc(sizeof(FBLK), "energy");
c = (FLOAT *) mem_alloc(sizeof(FHBLK), "c");
fthr = (FLOAT *) mem_alloc(sizeof(FHBLK), "fthr");
snrtmp = (F32 *) mem_alloc(sizeof(F2_32), "snrtmp");
if(init==0){
/* These dynamic memory allocations simulate "static" variables placed */
/* in the data space. Each mem_alloc() call here occurs only once at */
/* initialization time. The mem_free() function must not be called. */
numlines = (int *) mem_alloc(sizeof(ICB), "numlines");
partition = (int *) mem_alloc(sizeof(IHBLK), "partition");
cbval = (FLOAT *) mem_alloc(sizeof(FCB), "cbval");
rnorm = (FLOAT *) mem_alloc(sizeof(FCB), "rnorm");
window = (FLOAT *) mem_alloc(sizeof(FBLK), "window");
absthr = (FLOAT *) mem_alloc(sizeof(FHBLK), "absthr");
tmn = (double *) mem_alloc(sizeof(DCB), "tmn");
s = (FCB *) mem_alloc(sizeof(FCBCB), "s");
lthr = (FHBLK *) mem_alloc(sizeof(F2HBLK), "lthr");
r = (F2HBLK *) mem_alloc(sizeof(F22HBLK), "r");
phi_sav = (F2HBLK *) mem_alloc(sizeof(F22HBLK), "phi_sav");
i = sfreq + 0.5;
switch(i){
case 32000: sfreq_idx = 0; break;
case 44100: sfreq_idx = 1; break;
case 48000: sfreq_idx = 2; break;
default: printf("error, invalid sampling frequency: %d Hz\n",i);
exit(-1);
}
printf("absthr[][] sampling frequency index: %d\n",sfreq_idx);
read_absthr(absthr, sfreq_idx);
if(lay==1){
flush = 384;
syncsize = 1024;
sync_flush = 576;
}
else {
flush = 384*3.0/2.0;
syncsize = 1056;
sync_flush = syncsize - flush;
}
/* calculate HANN window coefficients */
/* for(i=0;i<BLKSIZE;i++)window[i]=0.5*(1-cos(2.0*PI*i/(BLKSIZE-1.0))); */
for(i=0;i<BLKSIZE;i++)window[i]=0.5*(1-cos(2.0*PI*(i-0.5)/BLKSIZE));
/* reset states used in unpredictability measure */
for(i=0;i<HBLKSIZE;i++){
r[0][0][i]=r[1][0][i]=r[0][1][i]=r[1][1][i]=0;
phi_sav[0][0][i]=phi_sav[1][0][i]=0;
phi_sav[0][1][i]=phi_sav[1][1][i]=0;
lthr[0][i] = 60802371420160.0;
lthr[1][i] = 60802371420160.0;
}
/*****************************************************************************
* Initialization: Compute the following constants for use later *
* partition[HBLKSIZE] = the partition number associated with each *
* frequency line *
* cbval[CBANDS] = the center (average) bark value of each *
* partition *
* numlines[CBANDS] = the number of frequency lines in each partition *
* tmn[CBANDS] = tone masking noise *
*****************************************************************************/
/* compute fft frequency multiplicand */
freq_mult = sfreq/BLKSIZE;
/* calculate fft frequency, then bval of each line (use fthr[] as tmp storage)*/
for(i=0;i<HBLKSIZE;i++){
temp1 = i*freq_mult;
j = 1;
while(temp1>crit_band[j])j++;
fthr[i]=j-1+(temp1-crit_band[j-1])/(crit_band[j]-crit_band[j-1]);
}
partition[0] = 0;
/* temp2 is the counter of the number of frequency lines in each partition */
temp2 = 1;
cbval[0]=fthr[0];
bval_lo=fthr[0];
for(i=1;i<HBLKSIZE;i++){
if((fthr[i]-bval_lo)>0.33){
partition[i]=partition[i-1]+1;
cbval[partition[i-1]] = cbval[partition[i-1]]/temp2;
cbval[partition[i]] = fthr[i];
bval_lo = fthr[i];
numlines[partition[i-1]] = temp2;
temp2 = 1;
}
else {
partition[i]=partition[i-1];
cbval[partition[i]] += fthr[i];
temp2++;
}
}
numlines[partition[i-1]] = temp2;
cbval[partition[i-1]] = cbval[partition[i-1]]/temp2;
/************************************************************************
* Now compute the spreading function, s[j][i], the value of the spread-*
* ing function, centered at band j, for band i, store for later use *
************************************************************************/
for(j=0;j<CBANDS;j++){
for(i=0;i<CBANDS;i++){
temp1 = (cbval[i] - cbval[j])*1.05;
if(temp1>=0.5 && temp1<=2.5){
temp2 = temp1 - 0.5;
temp2 = 8.0 * (temp2*temp2 - 2.0 * temp2);
}
else temp2 = 0;
temp1 += 0.474;
temp3 = 15.811389+7.5*temp1-17.5*sqrt((double) (1.0+temp1*temp1));
if(temp3 <= -100) s[i][j] = 0;
else {
temp3 = (temp2 + temp3)*LN_TO_LOG10;
s[i][j] = exp(temp3);
}
}
}
/* Calculate Tone Masking Noise values */
for(j=0;j<CBANDS;j++){
temp1 = 15.5 + cbval[j];
tmn[j] = (temp1>24.5) ? temp1 : 24.5;
/* Calculate normalization factors for the net spreading functions */
rnorm[j] = 0;
for(i=0;i<CBANDS;i++){
rnorm[j] += s[j][i];
}
}
init++;
}
/************************* End of Initialization *****************************/
switch(lay) {
case 1:
case 2:
for(i=0; i<lay; i++){
/*****************************************************************************
* Net offset is 480 samples (1056-576) for layer 2; this is because one must*
* stagger input data by 256 samples to synchronize psychoacoustic model with*
* filter bank outputs, then stagger so that center of 1024 FFT window lines *
* up with center of 576 "new" audio samples. *
* *
* For layer 1, the input data still needs to be staggered by 256 samples, *
* then it must be staggered again so that the 384 "new" samples are centered*
* in the 1024 FFT window. The net offset is then 576 and you need 448 "new"*
* samples for each iteration to keep the 384 samples of interest centered *
*****************************************************************************/
for(j=0; j<syncsize; j++){
if(j<(sync_flush))savebuf[j] = savebuf[j+flush];
else savebuf[j] = *buffer++;
if(j<BLKSIZE){
/**window data with HANN window***********************************************/
wsamp_r[j] = window[j]*((FLOAT) savebuf[j]);
wsamp_i[j] = 0;
}
}
/**Compute FFT****************************************************************/
fft(wsamp_r,wsamp_i,energy,phi,1024);
/*****************************************************************************
* calculate the unpredictability measure, given energy[f] and phi[f] *
*****************************************************************************/
/*only update data "age" pointers after you are done with both channels */
/*for layer 1 computations, for the layer 2 double computations, the pointers*/
/*are reset automatically on the second pass */
if(lay==2 || (lay==1 && chn==0) ){
if(new==0){new = 1; oldest = 1;}
else {new = 0; oldest = 0;}
if(old==0)old = 1; else old = 0;
}
for(j=0; j<HBLKSIZE; j++){
r_prime = 2.0 * r[chn][old][j] - r[chn][oldest][j];
phi_prime = 2.0 * phi_sav[chn][old][j] - phi_sav[chn][oldest][j];
r[chn][new][j] = sqrt((double) energy[j]);
phi_sav[chn][new][j] = phi[j];
temp1=r[chn][new][j] * cos((double) phi[j]) - r_prime * cos((double) phi_prime);
temp2=r[chn][new][j] * sin((double) phi[j]) - r_prime * sin((double) phi_prime);
temp3=r[chn][new][j] + fabs((double)r_prime);
if(temp3 != 0)c[j]=sqrt(temp1*temp1+temp2*temp2)/temp3;
else c[j] = 0;
}
/*****************************************************************************
* Calculate the grouped, energy-weighted, unpredictability measure, *
* grouped_c[], and the grouped energy. grouped_e[] *
*****************************************************************************/
for(j=1;j<CBANDS;j++){
grouped_e[j] = 0;
grouped_c[j] = 0;
}
grouped_e[0] = energy[0];
grouped_c[0] = energy[0]*c[0];
for(j=1;j<HBLKSIZE;j++){
grouped_e[partition[j]] += energy[j];
grouped_c[partition[j]] += energy[j]*c[j];
}
/*****************************************************************************
* convolve the grouped energy-weighted unpredictability measure *
* and the grouped energy with the spreading function, s[j][k] *
*****************************************************************************/
for(j=0;j<CBANDS;j++){
ecb[j] = 0;
cb[j] = 0;
for(k=0;k<CBANDS;k++){
if(s[j][k] != 0.0){
ecb[j] += s[j][k]*grouped_e[k];
cb[j] += s[j][k]*grouped_c[k];
}
}
if(ecb[j] !=0)cb[j] = cb[j]/ecb[j];
else cb[j] = 0;
}
/*****************************************************************************
* Calculate the required SNR for each of the frequency partitions *
* this whole section can be accomplished by a table lookup *
*****************************************************************************/
for(j=0;j<CBANDS;j++){
if(cb[j]<.05)cb[j]=0.05;
else if(cb[j]>.5)cb[j]=0.5;
tb = -0.434294482*log((double) cb[j])-0.301029996;
bc[j] = tmn[j]*tb + nmt*(1.0-tb);
k = cbval[j] + 0.5;
bc[j] = (bc[j] > bmax[k]) ? bc[j] : bmax[k];
bc[j] = exp((double) -bc[j]*LN_TO_LOG10);
}
/*****************************************************************************
* Calculate the permissible noise energy level in each of the frequency *
* partitions. Include absolute threshold and pre-echo controls *
* this whole section can be accomplished by a table lookup *
*****************************************************************************/
for(j=0;j<CBANDS;j++)
if(rnorm[j] && numlines[j])
nb[j] = ecb[j]*bc[j]/(rnorm[j]*numlines[j]);
else nb[j] = 0;
for(j=0;j<HBLKSIZE;j++){
/*temp1 is the preliminary threshold */
temp1=nb[partition[j]];
temp1=(temp1>absthr[j])?temp1:absthr[j];
/*do not use pre-echo control for layer 2 because it may do bad things to the*/
/* MUSICAM bit allocation algorithm */
if(lay==1){
fthr[j] = (temp1 < lthr[chn][j]) ? temp1 : lthr[chn][j];
temp2 = temp1 * 0.00316;
fthr[j] = (temp2 > fthr[j]) ? temp2 : fthr[j];
}
else fthr[j] = temp1;
lthr[chn][j] = LXMIN*temp1;
}
/*****************************************************************************
* Translate the 512 threshold values to the 32 filter bands of the coder *
*****************************************************************************/
for(j=0;j<193;j += 16){
minthres = 60802371420160.0;
sum_energy = 0.0;
for(k=0;k<17;k++){
if(minthres>fthr[j+k])minthres = fthr[j+k];
sum_energy += energy[j+k];
}
snrtmp[i][j/16] = sum_energy/(minthres * 17.0);
snrtmp[i][j/16] = 4.342944819 * log((double)snrtmp[i][j/16]);
}
for(j=208;j<(HBLKSIZE-1);j += 16){
minthres = 0.0;
sum_energy = 0.0;
for(k=0;k<17;k++){
minthres += fthr[j+k];
sum_energy += energy[j+k];
}
snrtmp[i][j/16] = sum_energy/minthres;
snrtmp[i][j/16] = 4.342944819 * log((double)snrtmp[i][j/16]);
}
/*****************************************************************************
* End of Psychoacuostic calculation loop *
*****************************************************************************/
}
for(i=0; i<32; i++){
if(lay==2)
snr32[i]=(snrtmp[0][i]>snrtmp[1][i])?snrtmp[0][i]:snrtmp[1][i];
else snr32[i]=snrtmp[0][i];
}
break;
case 3:
printf("layer 3 is not currently supported\n");
break;
default:
printf("error, invalid MPEG/audio coding layer: %d\n",lay);
}
/* These mem_free() calls must correspond with the mem_alloc() calls */
/* used at the beginning of this function to simulate "automatic" */
/* variables placed on the stack. */
mem_free((void **) &grouped_c);
mem_free((void **) &grouped_e);
mem_free((void **) &nb);
mem_free((void **) &cb);
mem_free((void **) &ecb);
mem_free((void **) &bc);
mem_free((void **) &wsamp_r);
mem_free((void **) &wsamp_i);
mem_free((void **) &phi);
mem_free((void **) &energy);
mem_free((void **) &c);
mem_free((void **) &fthr);
mem_free((void **) &snrtmp);
}
/******************************************************************************
routine to read in absthr table from a file.
******************************************************************************/
void read_absthr(absthr, table)
FLOAT *absthr;
int table;
{
FILE *fp;
long j,index;
float a;
char t[80];
char ta[16];
strcpy( ta, "absthr_0" );
switch(table){
case 0 : ta[7] = '0';
break;
case 1 : ta[7] = '1';
break;
case 2 : ta[7] = '2';
break;
default : printf("absthr table: Not valid table number\n");
}
if(!(fp = OpenTableFile(ta) ) ){
printf("Please check %s table\n", ta);
exit(1);
}
fgets(t, 150, fp);
sscanf(t, "table %ld", &index);
if(index != table){
printf("error in absthr table %s",ta);
exit(1);
}
for(j=0; j<HBLKSIZE; j++){
fgets(t,80,fp);
sscanf(t,"%f", &a);
absthr[j] = a;
}
fclose(fp);
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.