127 lines
2.5 KiB
C
127 lines
2.5 KiB
C
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#ifndef NEW_PLC
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#define NEW_PLC
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#endif
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float _celt_lpc(
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float *lpc, /* out: [0...p-1] LPC coefficients */
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const float *ac, /* in: [0...p] autocorrelation values */
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int p
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)
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{
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int i, j;
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float r;
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float error = ac[0];
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if (ac[0] == 0)
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{
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for (i = 0; i < p; i++)
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lpc[i] = 0;
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return 0;
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}
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for (i = 0; i < p; i++) {
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/* Sum up this iteration's reflection coefficient */
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float rr = -ac[i + 1];
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for (j = 0; j < i; j++)
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rr = rr - lpc[j]*ac[i - j];
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r = rr/(error+1e-15);
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/* Update LPC coefficients and total error */
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lpc[i] = r;
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for (j = 0; j < i>>1; j++)
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{
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float tmp = lpc[j];
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lpc[j] = lpc[j ] + r*lpc[i-1-j];
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lpc[i-1-j] = lpc[i-1-j] + r*tmp;
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}
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if (i & 1)
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lpc[j] = lpc[j] + lpc[j]*r;
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error = error - r*r*error;
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if (error<.00001*ac[0])
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break;
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}
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return error;
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}
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void fir(const float *x,
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const float *num,
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float *y,
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int N,
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int ord,
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float *mem)
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{
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int i,j;
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for (i=0;i<N;i++)
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{
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float sum = x[i];
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for (j=0;j<ord;j++)
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{
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sum += num[j]*mem[j];
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}
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for (j=ord-1;j>=1;j--)
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{
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mem[j]=mem[j-1];
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}
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mem[0] = x[i];
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y[i] = sum;
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}
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}
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void iir(const celt_word32 *x,
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const float *den,
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celt_word32 *y,
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int N,
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int ord,
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float *mem)
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{
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int i,j;
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for (i=0;i<N;i++)
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{
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float sum = x[i];
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for (j=0;j<ord;j++)
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{
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sum -= den[j]*mem[j];
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}
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for (j=ord-1;j>=1;j--)
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{
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mem[j]=mem[j-1];
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}
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mem[0] = sum;
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y[i] = sum;
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}
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}
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void _celt_autocorr(
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const float *x, /* in: [0...n-1] samples x */
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float *ac, /* out: [0...lag-1] ac values */
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const celt_word16 *window,
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int overlap,
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int lag,
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int n
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)
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{
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float d;
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int i;
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VARDECL(float, xx);
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SAVE_STACK;
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ALLOC(xx, n, float);
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for (i=0;i<n;i++)
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xx[i] = x[i];
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for (i=0;i<overlap;i++)
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{
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xx[i] *= (1./Q15ONE)*window[i];
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xx[n-i-1] *= (1./Q15ONE)*window[i];
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}
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while (lag>=0)
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{
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for (i = lag, d = 0; i < n; i++)
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d += x[i] * x[i-lag];
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ac[lag] = d;
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lag--;
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}
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ac[0] += 10;
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RESTORE_STACK;
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}
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