| /*---------------------------------------------------------------------------* |
| * chelmel4.c * |
| * * |
| * Copyright 2007, 2008 Nuance Communciations, Inc. * |
| * * |
| * Licensed under the Apache License, Version 2.0 (the 'License'); * |
| * you may not use this file except in compliance with the License. * |
| * * |
| * You may obtain a copy of the License at * |
| * http://www.apache.org/licenses/LICENSE-2.0 * |
| * * |
| * Unless required by applicable law or agreed to in writing, software * |
| * distributed under the License is distributed on an 'AS IS' BASIS, * |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * |
| * See the License for the specific language governing permissions and * |
| * limitations under the License. * |
| * * |
| *---------------------------------------------------------------------------*/ |
| |
| |
| |
| #include <stdlib.h> |
| #ifndef _RTT |
| #include <stdio.h> |
| #endif |
| #include <string.h> |
| #include <math.h> |
| #include <limits.h> |
| #include <assert.h> |
| |
| #include "hmm_desc.h" |
| #include "front.h" |
| #include "portable.h" |
| |
| #define DEBUG 0 |
| #define LOG_AS_PRINT 0 |
| |
| #define LPCMAX 100 |
| |
| |
| #if LOG_AS_PRINT /* BP temp hack */ |
| #define log_report printf |
| #endif |
| |
| #include "sh_down.h" |
| |
| |
| /* cepstrum_params has been broken into three functions: |
| filterbank_emulation - does preemp, window, fft and filtbank |
| gain_adjustment - estimates gain |
| cepstrum_params - does gain adj.(if on), spec corr and cos transform |
| This enables us to bypass gain adjustment. |
| */ |
| |
| //static void mel_cuberoot_offset(cepdata *fbo, cepdata *ch_off, int nf); |
| #if SPEC_CORRECT |
| static void mel_spectrum_correction(cepdata *fbo, cepdata *ch_gain, int nf); |
| #endif |
| static void mel_loglookup_with_offset(front_cep *cepobj, |
| front_channel *channel); |
| //static void mel_exp(cepdata *fbo, int nf); |
| //static void durbin(cepdata *a, cepdata *r, int n); |
| //static void lpc_to_cepstral_recursion(cepdata *c, cepdata *a, int nc, int n); |
| static void icostrans(cepdata *cs, cepdata fb[], cepdata cep[], int nf, int nc); |
| |
| |
| void cepstrum_params(front_channel *channel, front_wave *waveobj, |
| front_freq *freqobj, front_cep *cepobj) |
| { |
| #if SPEC_CORRECT |
| /* 2.30 Apply a spectrum correction */ |
| if (cepobj->mel_loop) |
| mel_spectrum_correction(freqobj->filterbank, cepobj->mel_loop, channel->num_freq); |
| #endif |
| /* 2.33 Calculate log dB energy values */ |
| mel_loglookup_with_offset(cepobj, channel); |
| #if DEBUG |
| log_report("Filterbank output: "); |
| write_scaled_frames(freqobj->nf, 1, channel->filterbank, D_FIXED, 1 / (float)LOG_SCALE); |
| #endif |
| |
| /* 2.34 Cosine transformation */ |
| icostrans(cepobj->cs, channel->filterbank, channel->cep, |
| channel->num_freq, cepobj->mel_dim); |
| |
| #if DEBUG |
| log_report("Cepstrum coefficients: "); |
| write_scaled_frames((cepobj->mel_dim + 1), 1, channel->cep, D_FIXED, (float)1 / (0x01 << (LOG_SCALE_SHIFT + COSINE_TABLE_SHIFT))); |
| #endif |
| return; |
| } |
| |
| static void icostrans(cepdata *cs, cepdata fb[], cepdata cep[], int nf, int nc) |
| /* |
| ** inv rotated-cosine transform |
| ** ref Davis and Mermelstein, ASSP 1980 */ |
| { |
| int i, j; |
| cepdata *cp; |
| cepdata temp; |
| |
| for (i = 0; i <= nc; i++) |
| { |
| cp = &cs[i*nf]; |
| for (j = 0, temp = 0; j < nf; j++) |
| temp += fb[j] * cp[j]; |
| cep[i] = temp; |
| } |
| return; |
| } |
| |
| #if SPEC_CORRECT |
| static void mel_spectrum_correction(cepdata *fbo, cepdata *ch_gain, int nf) |
| /* |
| ** pwr spect -> filter bank output */ |
| { |
| int i; |
| |
| for (i = 0;i < nf; i++) |
| fbo[i] = fbo[i] * ch_gain[i]; /* TODO: Fixedpt scale up and down */ |
| return; |
| } |
| #endif |
| |
| static void mel_loglookup_with_offset(front_cep *cepobj, |
| front_channel *channel) |
| /* |
| ** pwr spect -> filter bank output */ |
| { |
| int ii; |
| |
| if (channel->shift > 0) |
| for (ii = 0; ii < channel->num_freq; ii++) |
| { |
| channel->filterbank[ii] = (cepdata) log_lookup(&cepobj->logtab, |
| (int)(channel->filterbank[ii] + |
| SHIFT_DOWN(cepobj->mel_offset[ii], channel->shift)), |
| channel->shift); |
| } |
| else |
| for (ii = 0; ii < channel->num_freq; ii++) |
| { |
| channel->filterbank[ii] = (cepdata) log_lookup(&cepobj->logtab, |
| (int)(channel->filterbank[ii] + |
| SHIFT_UP(cepobj->mel_offset[ii], -channel->shift)), |
| channel->shift); |
| } |
| |
| return; |
| } |
| |
| //static void mel_exp(cepdata *fbo, int nf) |
| ///* |
| //** pwr spect -> filter bank output */ |
| //{ |
| // int i; |
| // for (i = 0; i < nf; i++) |
| // { |
| // fbo[i] = (cepdata) exp((double) fbo[i]); |
| // } |
| // return; |
| //} |
| // |
| //static void durbin( |
| // cepdata *a, /* lpc coefficients */ |
| // cepdata *r, /* autocorrelation coefficients */ |
| // int n) /* order of lpc analysis */ |
| //{ |
| // int i, j; |
| // cepdata A[LPCMAX+1][LPCMAX+1], sum; |
| // cepdata k[LPCMAX+1]; |
| // cepdata e[LPCMAX+1]; |
| // |
| // e[0] = r[0]; |
| // for (i = 1; i <= n; i++) |
| // { |
| // sum = 0; |
| // for (j = 1; j <= (i - 1); j++) |
| // { |
| // sum += A[j][i-1] * r[i-j]; |
| // } |
| // k[i] = -(r[i] + sum) / e[i-1]; |
| // A[i][i] = k[i] ; |
| // for (j = 1; j <= (i - 1); j++) |
| // { |
| // A[j][i] = A[j][i-1] + k[i] * A[i-j][i-1]; |
| // } |
| // e[i] = (1 - k[i] * k[i]) * e[i-1]; |
| // } |
| // for (j = 1 ; j <= n; j++) |
| // { |
| // a[j] = A[j][n]; |
| // } |
| // |
| // a[0] = (cepdata) 1.0 ; |
| // return; |
| //} |
| // |
| //static void lpc_to_cepstral_recursion( |
| // cepdata *c, /* cepstral coefficients */ |
| // cepdata *a, /* lpc coeffiecients */ |
| // int nc, /* order of cepstra */ |
| // int n) /* order of lpc */ |
| //{ |
| // int k, i; |
| // cepdata sum; |
| // |
| // ASSERT(nc < LPCMAX); |
| // |
| // for (i = n + 1; i <= nc; i++) |
| // { |
| // a[i] = (cepdata) 0.0; |
| // } |
| // /* if lpc order less */ |
| // /* than cepstral order */ |
| // /* define higher lpccos */ |
| // |
| // for (i = 1; i <= nc; i++) |
| // { |
| // sum = (cepdata) 0.0; |
| // for (k = 1; k <= (i - 1); k++) |
| // { |
| // sum = sum + k * c[k] * a[i-k]; /* TODO: fixedpt range for mult */ |
| // } |
| // c[i] = -a[i] - (sum / i); /* cepstral calculated */ |
| // /* to <=nc in icostrans */ |
| // /* so I shall do the */ /* same here */ |
| // } |
| //} |
| |
