GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/lpc.c Lines: 137 150 91.3 %
Date: 2021-04-18 10:33:33 Branches: 73 86 84.9 %

Line Branch Exec Source
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/*
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 * LPC utility code
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 * Copyright (c) 2006  Justin Ruggles <justin.ruggles@gmail.com>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "libavutil/common.h"
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#include "libavutil/lls.h"
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#include "libavutil/mem_internal.h"
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#define LPC_USE_DOUBLE
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#include "lpc.h"
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#include "libavutil/avassert.h"
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/**
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 * Apply Welch window function to audio block
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 */
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3969
static void lpc_apply_welch_window_c(const int32_t *data, int len,
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                                     double *w_data)
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{
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    int i, n2;
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    double w;
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    double c;
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3969
    n2 = (len >> 1);
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3969
    c = 2.0 / (len - 1.0);
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3969
    if (len & 1) {
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1050
        for(i=0; i<n2; i++) {
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1048
            w = c - i - 1.0;
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1048
            w = 1.0 - (w * w);
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1048
            w_data[i] = data[i] * w;
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1048
            w_data[len-1-i] = data[len-1-i] * w;
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        }
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2
        return;
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    }
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3967
    w_data+=n2;
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3967
      data+=n2;
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9253857
    for(i=0; i<n2; i++) {
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9249890
        w = c - n2 + i;
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9249890
        w = 1.0 - (w * w);
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9249890
        w_data[-i-1] = data[-i-1] * w;
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9249890
        w_data[+i  ] = data[+i  ] * w;
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    }
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}
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/**
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 * Calculate autocorrelation data from audio samples
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 * A Welch window function is applied before calculation.
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 */
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7733
static void lpc_compute_autocorr_c(const double *data, int len, int lag,
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                                   double *autoc)
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{
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    int i, j;
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57574
    for(j=0; j<lag; j+=2){
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49841
        double sum0 = 1.0, sum1 = 1.0;
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141092269
        for(i=j; i<len; i++){
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141042428
            sum0 += data[i] * data[i-j];
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141042428
            sum1 += data[i] * data[i-j-1];
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        }
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49841
        autoc[j  ] = sum0;
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49841
        autoc[j+1] = sum1;
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    }
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7733
    if(j==lag){
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7317
        double sum = 1.0;
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10279207
        for(i=j-1; i<len; i+=2){
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10271890
            sum += data[i  ] * data[i-j  ]
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10271890
                 + data[i+1] * data[i-j+1];
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        }
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7317
        autoc[j] = sum;
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    }
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7733
}
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/**
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 * Quantize LPC coefficients
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 */
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11765
static void quantize_lpc_coefs(double *lpc_in, int order, int precision,
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                               int32_t *lpc_out, int *shift, int min_shift,
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                               int max_shift, int zero_shift)
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{
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    int i;
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    double cmax, error;
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    int32_t qmax;
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    int sh;
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    /* define maximum levels */
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11765
    qmax = (1 << (precision - 1)) - 1;
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    /* find maximum coefficient value */
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11765
    cmax = 0.0;
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69630
    for(i=0; i<order; i++) {
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57865
        cmax= FFMAX(cmax, fabs(lpc_in[i]));
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    }
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    /* if maximum value quantizes to zero, return all zeros */
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11765
    if(cmax * (1 << max_shift) < 1.0) {
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        *shift = zero_shift;
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        memset(lpc_out, 0, sizeof(int32_t) * order);
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        return;
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    }
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    /* calculate level shift which scales max coeff to available bits */
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11765
    sh = max_shift;
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32239
    while((cmax * (1 << sh) > qmax) && (sh > min_shift)) {
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20474
        sh--;
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    }
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    /* since negative shift values are unsupported in decoder, scale down
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       coefficients instead */
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11765
    if(sh == 0 && cmax > qmax) {
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        double scale = ((double)qmax) / cmax;
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        for(i=0; i<order; i++) {
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            lpc_in[i] *= scale;
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        }
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    }
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    /* output quantized coefficients and level shift */
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11765
    error=0;
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69630
    for(i=0; i<order; i++) {
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57865
        error -= lpc_in[i] * (1 << sh);
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57865
        lpc_out[i] = av_clip(lrintf(error), -qmax, qmax);
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57865
        error -= lpc_out[i];
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    }
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11765
    *shift = sh;
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}
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8933
static int estimate_best_order(double *ref, int min_order, int max_order)
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{
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    int i, est;
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8933
    est = min_order;
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64596
    for(i=max_order-1; i>=min_order-1; i--) {
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64422
        if(ref[i] > 0.10) {
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8759
            est = i+1;
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8759
            break;
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        }
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    }
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8933
    return est;
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}
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int ff_lpc_calc_ref_coefs(LPCContext *s,
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                          const int32_t *samples, int order, double *ref)
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{
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    double autoc[MAX_LPC_ORDER + 1];
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    s->lpc_apply_welch_window(samples, s->blocksize, s->windowed_samples);
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    s->lpc_compute_autocorr(s->windowed_samples, s->blocksize, order, autoc);
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    compute_ref_coefs(autoc, order, ref, NULL);
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    return order;
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}
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double ff_lpc_calc_ref_coefs_f(LPCContext *s, const float *samples, int len,
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                               int order, double *ref)
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{
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    int i;
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3764
    double signal = 0.0f, avg_err = 0.0f;
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3764
    double autoc[MAX_LPC_ORDER+1] = {0}, error[MAX_LPC_ORDER+1] = {0};
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3764
    const double a = 0.5f, b = 1.0f - a;
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    /* Apply windowing */
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1090012
    for (i = 0; i <= len / 2; i++) {
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1086248
        double weight = a - b*cos((2*M_PI*i)/(len - 1));
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1086248
        s->windowed_samples[i] = weight*samples[i];
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1086248
        s->windowed_samples[len-1-i] = weight*samples[len-1-i];
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    }
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3764
    s->lpc_compute_autocorr(s->windowed_samples, len, order, autoc);
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3764
    signal = autoc[0];
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3764
    compute_ref_coefs(autoc, order, ref, error);
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46852
    for (i = 0; i < order; i++)
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43088
        avg_err = (avg_err + error[i])/2.0f;
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3764
    return signal/avg_err;
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}
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/**
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 * Calculate LPC coefficients for multiple orders
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 *
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 * @param lpc_type LPC method for determining coefficients,
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 *                 see #FFLPCType for details
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 */
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9169
int ff_lpc_calc_coefs(LPCContext *s,
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                      const int32_t *samples, int blocksize, int min_order,
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                      int max_order, int precision,
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                      int32_t coefs[][MAX_LPC_ORDER], int *shift,
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                      enum FFLPCType lpc_type, int lpc_passes,
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                      int omethod, int min_shift, int max_shift, int zero_shift)
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{
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    double autoc[MAX_LPC_ORDER+1];
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9169
    double ref[MAX_LPC_ORDER] = { 0 };
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    double lpc[MAX_LPC_ORDER][MAX_LPC_ORDER];
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9169
    int i, j, pass = 0;
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    int opt_order;
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    av_assert2(max_order >= MIN_LPC_ORDER && max_order <= MAX_LPC_ORDER &&
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           lpc_type > FF_LPC_TYPE_FIXED);
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9169
    av_assert0(lpc_type == FF_LPC_TYPE_CHOLESKY || lpc_type == FF_LPC_TYPE_LEVINSON);
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    /* reinit LPC context if parameters have changed */
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9169
    if (blocksize != s->blocksize || max_order != s->max_order ||
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9156
        lpc_type  != s->lpc_type) {
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        ff_lpc_end(s);
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        ff_lpc_init(s, blocksize, max_order, lpc_type);
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    }
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9169
    if(lpc_passes <= 0)
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2589
        lpc_passes = 2;
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9169
    if (lpc_type == FF_LPC_TYPE_LEVINSON || (lpc_type == FF_LPC_TYPE_CHOLESKY && lpc_passes > 1)) {
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9169
        s->lpc_apply_welch_window(samples, blocksize, s->windowed_samples);
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9169
        s->lpc_compute_autocorr(s->windowed_samples, blocksize, max_order, autoc);
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9169
        compute_lpc_coefs(autoc, max_order, &lpc[0][0], MAX_LPC_ORDER, 0, 1);
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106947
        for(i=0; i<max_order; i++)
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97778
            ref[i] = fabs(lpc[i][i]);
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238
9169
        pass++;
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    }
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241
9169
    if (lpc_type == FF_LPC_TYPE_CHOLESKY) {
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182
        LLSModel *m = s->lls_models;
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182
        LOCAL_ALIGNED(32, double, var, [FFALIGN(MAX_LPC_ORDER+1,4)]);
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182
        double av_uninit(weight);
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182
        memset(var, 0, FFALIGN(MAX_LPC_ORDER+1,4)*sizeof(*var));
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1638
        for(j=0; j<max_order; j++)
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1456
            m[0].coeff[max_order-1][j] = -lpc[max_order-1][j];
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250
364
        for(; pass<lpc_passes; pass++){
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182
            avpriv_init_lls(&m[pass&1], max_order);
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253
182
            weight=0;
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836626
            for(i=max_order; i<blocksize; i++){
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8364440
                for(j=0; j<=max_order; j++)
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7527996
                    var[j]= samples[i-j];
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258
836444
                if(pass){
259
                    double eval, inv, rinv;
260
836444
                    eval= m[pass&1].evaluate_lls(&m[(pass-1)&1], var+1, max_order-1);
261
836444
                    eval= (512>>pass) + fabs(eval - var[0]);
262
836444
                    inv = 1/eval;
263
836444
                    rinv = sqrt(inv);
264
8364440
                    for(j=0; j<=max_order; j++)
265
7527996
                        var[j] *= rinv;
266
836444
                    weight += inv;
267
                }else
268
                    weight++;
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270
836444
                m[pass&1].update_lls(&m[pass&1], var);
271
            }
272
182
            avpriv_solve_lls(&m[pass&1], 0.001, 0);
273
        }
274
275
1638
        for(i=0; i<max_order; i++){
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13104
            for(j=0; j<max_order; j++)
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11648
                lpc[i][j]=-m[(pass-1)&1].coeff[i][j];
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1456
            ref[i]= sqrt(m[(pass-1)&1].variance[i] / weight) * (blocksize - max_order) / 4000;
279
        }
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1456
        for(i=max_order-1; i>0; i--)
281
1274
            ref[i] = ref[i-1] - ref[i];
282
    }
283
284
9169
    opt_order = max_order;
285
286
9169
    if(omethod == ORDER_METHOD_EST) {
287
8933
        opt_order = estimate_best_order(ref, min_order, max_order);
288
8933
        i = opt_order-1;
289
8933
        quantize_lpc_coefs(lpc[i], i+1, precision, coefs[i], &shift[i],
290
                           min_shift, max_shift, zero_shift);
291
    } else {
292
3068
        for(i=min_order-1; i<max_order; i++) {
293
2832
            quantize_lpc_coefs(lpc[i], i+1, precision, coefs[i], &shift[i],
294
                               min_shift, max_shift, zero_shift);
295
        }
296
    }
297
298
9169
    return opt_order;
299
}
300
301
66
av_cold int ff_lpc_init(LPCContext *s, int blocksize, int max_order,
302
                        enum FFLPCType lpc_type)
303
{
304
66
    s->blocksize = blocksize;
305
66
    s->max_order = max_order;
306
66
    s->lpc_type  = lpc_type;
307
308
66
    s->windowed_buffer = av_mallocz((blocksize + 2 + FFALIGN(max_order, 4)) *
309
                                    sizeof(*s->windowed_samples));
310
66
    if (!s->windowed_buffer)
311
        return AVERROR(ENOMEM);
312
66
    s->windowed_samples = s->windowed_buffer + FFALIGN(max_order, 4);
313
314
66
    s->lpc_apply_welch_window = lpc_apply_welch_window_c;
315
66
    s->lpc_compute_autocorr   = lpc_compute_autocorr_c;
316
317
    if (ARCH_X86)
318
66
        ff_lpc_init_x86(s);
319
320
66
    return 0;
321
}
322
323
66
av_cold void ff_lpc_end(LPCContext *s)
324
{
325
66
    av_freep(&s->windowed_buffer);
326
66
}