disto.c
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- /**************************************************************************
- *
- * ROUTINE
- * distortion
- *
- * FUNCTION
- *
- * computes distortion/distance measures and likelihood ratio
- *
- * SYNOPSIS
- *
- * subroutine distortion(s, ts, ws, l, no, dm, sumdm, framedm)
- *
- * formal
- *
- * data I/O
- * name type type function
- * -------------------------------------------------------------------
- * s float i "reference" speech input
- * ts short i "test" speech input
- * ws float i Hamming window, length l
- * l int i length of comparison
- * no int i filter order
- * dm float o distances array (subframe)
- * sumdm float o distances array (current sum)
- * framedm int o number of subframes
- *
- ***************************************************************************
- *
- * DESCRIPTION
- *
- * Calculate distortions/distances (log spectral error, etc.).
- * See the first reference below for a complete description. A
- * "reference" system is compared against a "test" system. Because
- * of the nonsymetric nature of the Itakura-Saito measure which some
- * of these distortion measures are based, poorer measures will be
- * obtained if the "reference" and "test" systems are reversed.
- * Because of gain uncertainties, a few measures are reported.
- * (Peter Kroon generally uses the measure DM(4).)
- *
- ***************************************************************************
- *
- * CALLED BY
- *
- * celp
- *
- * CALLS
- *
- * cor dist
- *
- ***************************************************************************
- *
- * REFERENCES
- *
- * "Distance Measures for Speech Processing", A.H. Gray and J.D. Markel,
- * IEEE Trans. on ASSP, Vol. ASSP-24, no. 5, Oct. 1976
- *
- * "Quantization and Bit Allocation in Speech Processing",
- * A.H. Gray and J.D. Markel,IEEE Trans. on ASSP, Vol. ASSP-24
- * no. 6, Dec. 1976
- *
- * "A Note on Quantization and Bit Allocation in Speech Processing",
- * A.H. Gray and J.D. Markel,IEEE Trans. on ASSP, Vol. ASSP-25
- * no. 3, June 1977
- *
- **************************************************************************/
- #include "ccsub.h"
- distortion(s, ts, ws, l, no, dm, sumdm, framedm)
- int l, no, *framedm;
- short ts[];
- float s[], ws[], dm[], sumdm[];
- {
- float tsw[MAXL], ssw[MAXL], c0hp, chp[MAXNO+1], c0tsw, ctsw[MAXNO+1];
- int j;
- /* *apply Hamming window */
- for (j = 0; j < l; j++)
- {
- ssw[j] = ws[j] * s[j];
- tsw[j] = ws[j] * (float)ts[j];
- }
- /* *calculate autocorrelation sequences */
- cor(ssw, l, no, &c0hp, chp);
- cor(tsw, l, no, &c0tsw, ctsw);
- /* *rearrange arrays for dist */
- for (j = no; j > 0; j--)
- {
- chp[j] = chp[j-1];
- ctsw[j] = ctsw[j-1];
- }
- chp[0] = c0hp;
- ctsw[0] = c0tsw;
- /* *find distances */
- if (chp[0] != 0.0 && ctsw[0] != 0.0)
- {
- j = no * 4;
- dist(no, j, chp, ctsw, dm, sumdm, framedm);
- }
- }