decode.c

mpeg layerI II III, support window and linux

    }
}

/*************************** Layer II stuff ************************/

void II_buffer_sample(bs,sample,bit_alloc,fr_ps)
unsigned int FAR sample[2][3][SBLIMIT];
unsigned int bit_alloc[2][SBLIMIT];
Bit_stream_struc *bs;
frame_params *fr_ps;
{
    int i,j,k,m;
    int stereo = fr_ps->stereo;
    int sblimit = fr_ps->sblimit;
    int jsbound = fr_ps->jsbound;
    al_table *alloc = fr_ps->alloc;

    printf("debug : layer II buffer sample\n");

    for (i=0;i<sblimit;i++) for (j=0;j<((i<jsbound)?stereo:1);j++) {
        if (bit_alloc[j][i]) {
            /* check for grouping in subband */
            if ((*alloc)[i][bit_alloc[j][i]].group==3)
                for (m=0;m<3;m++) {
                    k = (*alloc)[i][bit_alloc[j][i]].bits;
                    sample[j][m][i] = (unsigned int) getbits(bs,k);
		    printf("bound=%d,ch=%d,direct sample,sample[%d]=0x%x,bitnum=%d\n",i,j,m,sample[j][m][i],k);
                }
            else {              /* bit_alloc = 3, 5, 9 */
                unsigned int nlevels, c=0;

                nlevels = (*alloc)[i][bit_alloc[j][i]].steps;
                k=(*alloc)[i][bit_alloc[j][i]].bits;
                c = (unsigned int) getbits(bs, k);
		printf("bound=%d,ch=%d,coded sample,sample=0x%x\n",i,j,c);
                for (k=0;k<3;k++) {
                    sample[j][k][i] = c % nlevels;
                    c /= nlevels;
		    printf("bound=%d,ch=%d,deccode sample %d =0x%x\n",i,j,k,sample[j][k][i]);
                }
            }
        }
        else {                  /* for no sample transmitted */
            for (k=0;k<3;k++) sample[j][k][i] = 0;
	    printf("bound=%d,ch=%d, sample 0_1_2=0\n",i,j);
        }
        if(stereo == 2 && i>= jsbound) /* joint stereo : copy L to R */ {
            for (k=0;k<3;k++) sample[1][k][i] = sample[0][k][i];
	    printf("copy L to R, bound=%d,sample=0x%x\n",i,sample[0][k][i]);
	}
	
    }
    for (i=sblimit;i<SBLIMIT;i++) for (j=0;j<stereo;j++) {
	for (k=0;k<3;k++) 
       		 sample[j][k][i] = 0;
	 printf("bound=%d,ch=%d, sample 0_1_2=0\n",i,j);
    }
}

/**************************************************************
/*
/*   Restore the compressed sample to a factional number.
/*   first complement the MSB of the sample
/*    for layer I :
/*    Use s = (s' + 2^(-nb+1) ) * 2^nb / (2^nb-1)
/*   for Layer II :
/*   Use the formula s = s' * c + d
/*
/**************************************************************/

static double c[17] = { 1.33333333333, 1.60000000000, 1.14285714286,
                        1.77777777777, 1.06666666666, 1.03225806452,
                        1.01587301587, 1.00787401575, 1.00392156863,
                        1.00195694716, 1.00097751711, 1.00048851979,
                        1.00024420024, 1.00012208522, 1.00006103888,
                        1.00003051851, 1.00001525902 };

static double d[17] = { 0.500000000, 0.500000000, 0.250000000, 0.500000000,
                        0.125000000, 0.062500000, 0.031250000, 0.015625000,
                        0.007812500, 0.003906250, 0.001953125, 0.0009765625,
                        0.00048828125, 0.00024414063, 0.00012207031,
                        0.00006103516, 0.00003051758 };

/************************** Layer II stuff ************************/

void II_dequantize_sample(sample, bit_alloc, fraction, fr_ps)
unsigned int FAR sample[2][3][SBLIMIT];
unsigned int bit_alloc[2][SBLIMIT];
double FAR fraction[2][3][SBLIMIT];
frame_params *fr_ps;
{
    int i, j, k, x;
    int stereo = fr_ps->stereo;
    int sblimit = fr_ps->sblimit;
    al_table *alloc = fr_ps->alloc;

    printf("II dequantize\n");

    for (i=0;i<sblimit;i++)  for (j=0;j<3;j++) for (k=0;k<stereo;k++) {
        if (bit_alloc[k][i]) {

            /* locate MSB in the sample */
            x = 0;
#ifndef MS_DOS
            while ((1L<<x) < (*alloc)[i][bit_alloc[k][i]].steps) x++;
#else
            /* microsoft C thinks an int is a short */
            while (( (unsigned long) (1L<<(long)x) <
                    (unsigned long)( (*alloc)[i][bit_alloc[k][i]].steps)
                    ) && ( x < 16) ) x++;
#endif

            /* MSB inversion */
            if (((sample[k][j][i] >> x-1) & 1) == 1)
                fraction[k][j][i] = 0.0;
            else  fraction[k][j][i] = -1.0;

            /* Form a 2's complement sample */
            fraction[k][j][i] += (double) (sample[k][j][i] & ((1<<x-1)-1)) /
                (double) (1L<<x-1);

            /* Dequantize the sample */
            fraction[k][j][i] += d[(*alloc)[i][bit_alloc[k][i]].quant];
            fraction[k][j][i] *= c[(*alloc)[i][bit_alloc[k][i]].quant];
        }
        else fraction[k][j][i] = 0.0;

	printf("sb=%d, ch=%d, grp = %d,sample =%d,x=%d,c=%f,d=%f,fract = %f\n",i,k,j,sample[k][j][i],x,c[(*alloc)[i][bit_alloc[k][i]].quant],d[(*alloc)[i][bit_alloc[k][i]].quant],fraction[k][j][i]);
    }
    for (i=sblimit;i<SBLIMIT;i++) for (j=0;j<3;j++) for(k=0;k<stereo;k++)
        fraction[k][j][i] = 0.0;
}

/***************************** Layer I stuff ***********************/

void I_dequantize_sample(sample, fraction, bit_alloc, fr_ps)
unsigned int FAR sample[2][3][SBLIMIT];
unsigned int bit_alloc[2][SBLIMIT];
double FAR fraction[2][3][SBLIMIT];
frame_params *fr_ps;
{
    int i, nb, k;
    int stereo = fr_ps->stereo;
    int sblimit = fr_ps->sblimit;

    printf("L1 deauantize\n");

    for (i=0;i<SBLIMIT;i++)
        for (k=0;k<stereo;k++) {
            if (bit_alloc[k][i]) {
                nb = bit_alloc[k][i] + 1;
                if (((sample[k][0][i] >> nb-1) & 1) == 1) fraction[k][0][i] = 0.0;
                else fraction[k][0][i] = -1.0;
                fraction[k][0][i] += (double) (sample[k][0][i] & ((1<<nb-1)-1)) /
                    (double) (1L<<nb-1);

                fraction[k][0][i] =
                    (double) (fraction[k][0][i]+1.0/(double)(1L<<nb-1)) *
                        (double) (1L<<nb) / (double) ((1L<<nb)-1);
            }
            else fraction[k][0][i] = 0.0;
            printf("bound = %d, channel = %d, fraction = %lf\n",i,k,fraction[k][0][i]);
        }
}

/************************************************************
/*
/*   Restore the original value of the sample ie multiply
/*    the fraction value by its scalefactor.
/*
/************************************************************/

/************************* Layer II Stuff **********************/

void II_denormalize_sample(fraction, scale_index,fr_ps,x)
double FAR fraction[2][3][SBLIMIT];
unsigned int scale_index[2][3][SBLIMIT];
frame_params *fr_ps;
int x;
{
    int i,j,k;
    int stereo = fr_ps->stereo;
    int sblimit = fr_ps->sblimit;

    printf("II_denormalization\n");
    for (i=0;i<sblimit;i++) for (j=0;j<stereo;j++) {
	printf("f0=%f, f1=%f, f2=%f, m=%f\n",fraction[j][0][i],fraction[j][1][i],fraction[j][2][i],multiple[scale_index[j][x][i]]);
	fraction[j][0][i] *= multiple[scale_index[j][x][i]];
        fraction[j][1][i] *= multiple[scale_index[j][x][i]];
        fraction[j][2][i] *= multiple[scale_index[j][x][i]];
	printf("mf0=%f, mf1=%f, mf2=%f\n",fraction[j][0][i],fraction[j][1][i],fraction[j][2][i]);
    }

}

/**************************** Layer I stuff ******************************/

void I_denormalize_sample(fraction,scale_index,fr_ps)
double FAR fraction[2][3][SBLIMIT];
unsigned int scale_index[2][3][SBLIMIT];
frame_params *fr_ps;
{
    int i,j,k;
    int stereo = fr_ps->stereo;
    int sblimit = fr_ps->sblimit;

    printf("L1 denormalize\n");
    for (i=0;i<SBLIMIT;i++) for (j=0;j<stereo;j++) {
        fraction[j][0][i] *= multiple[scale_index[j][0][i]];
        printf("bound = %d, channel = %d, fraction = %lf, multi = %lf\n",i,j, fraction[j][0][i], multiple[scale_index[j][0][i]]);
    }
}

/*****************************************************************
/*
/* The following are the subband synthesis routines. They apply
/* to both layer I and layer II stereo or mono. The user has to
/* decide what parameters are to be passed to the routines.
/*
/***************************************************************/

/*************************************************************
/*
/*   Pass the subband sample through the synthesis window
/*
/**************************************************************/

/* create in synthesis filter */

void create_syn_filter(filter,fp)
double FAR filter[64][SBLIMIT];
FILE *fp;
{
    register int i,k;

    for (i=0; i<64; i++)
        for (k=0; k<32; k++) {
            if ((filter[i][k] = 1e9*cos((double)((PI64*i+PI4)*(2*k+1)))) >= 0)
                modf(filter[i][k]+0.5, &filter[i][k]);
            else
                modf(filter[i][k]-0.5, &filter[i][k]);
            filter[i][k] *= 1e-9;
            
        }
}

/***************************************************************
/*
/*   Window the restored sample
/*
/***************************************************************/

/* read in synthesis window */

void read_syn_window(window)
double FAR window[HAN_SIZE];
{
    int i,j[4];
    FILE *fp;
    double f[4];
    char t[150];

    if (!(fp = OpenTableFile("dewindow") )) {
        printf("Please check synthesis window table 'dewindow'\n");
        exit(1);
    }
    for (i=0;i<512;i+=4) {
        fgets(t, 150, fp);
        sscanf(t,"D[%d] = %lf D[%d] = %lf D[%d] = %lf D[%d] = %lf\n",
               j, f,j+1,f+1,j+2,f+2,j+3,f+3);
        if (i==j[0]) {
            window[i] = f[0];
            window[i+1] = f[1];
            window[i+2] = f[2];
            window[i+3] = f[3];
        }
        else {
            printf("Check index in synthesis window table\n");
            exit(1);
        }
        fgets(t,150,fp);
    }
    fclose(fp);


    
}

int SubBandSynthesis (bandPtr, channel, samples,fp)
double *bandPtr;
int channel;
OUTPUT_TYPE *samples;
FILE *fp;
{
    register int i,j,k;
    register double *bufOffsetPtr, sum;
    register long foo;
    static int init = 1;
    typedef double NN[64][32];
    static NN FAR *filter;
    typedef double BB[2][2*HAN_SIZE];
    static BB FAR *buf;
    static int bufOffset[2] = {64,64};
    static double FAR *window;
    int clip = 0;               /* count & return how many samples clipped */

    //printf("SubBandSynthesis, channel = %d\n",channel);

    if (init) {
        buf = (BB FAR *) mem_alloc(sizeof(BB),"BB");
        filter = (NN FAR *) mem_alloc(sizeof(NN), "NN");
        create_syn_filter(*filter,fp);
        window = (double FAR *) mem_alloc(sizeof(double) * HAN_SIZE, "WIN");
        read_syn_window(window);
        init = 0;
    }
/*    if (channel == 0) */
    bufOffset[channel] = (bufOffset[channel] - 64) & 0x3ff;
    bufOffsetPtr = &((*buf)[channel][bufOffset[channel]]);
    

    //printf("Han_aize = %d, bufoffset  = 0x%x\n",HAN_SIZE,bufOffset[channel]);

    //for(i=0;i<32;i++) 
	      //printf("banddata[%d]=%f\n",i,bandPtr[i]);

    for (i=0; i<64; i++) {
        sum = 0;
        for (k=0; k<32; k++) {
            sum += bandPtr[k] * (*filter)[i][k];
         }
        bufOffsetPtr[i] = sum;

	//printf("V[%d] = %f\n",i,sum);        
    }
    /*  S(i,j) = D(j+32i) * U(j+32i+((i+1)>>1)*64)  */
    /*  samples(i,j) = MWindow(j+32i) * bufPtr(j+32i+((i+1)>>1)*64)  */
    for (j=0; j<32; j++) {
        sum = 0;
        for (i=0; i<16; i++) {
            k = j + (i<<5);
            sum += window[k] * (*buf) [channel] [( (k + ( ((i+1)>>1) <<6) ) +
                                                  bufOffset[channel]) & 0x3ff];
        }

/*      Casting truncates towards zero for both positive and negative numbers,
        the result is cross-over distortion,  1995-07-12 shn */

        if(sum > 0)
        {
          foo = (long)(sum * (double) SCALE + (double)0.5);
        }