GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/opusenc_utils.h Lines: 0 31 0.0 %
Date: 2019-11-20 04:07:19 Branches: 0 12 0.0 %

Line Branch Exec Source
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/*
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 * Opus encoder
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 * Copyright (c) 2017 Rostislav Pehlivanov <atomnuker@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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#ifndef AVCODEC_OPUSENC_UTILS_H
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#define AVCODEC_OPUSENC_UTILS_H
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#include "opus.h"
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typedef struct FFBesselFilter {
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    float a[3];
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    float b[2];
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    float x[3];
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    float y[3];
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} FFBesselFilter;
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/* Fills the coefficients, returns 1 if filter will be unstable */
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static inline int bessel_reinit(FFBesselFilter *s, float n, float f0, float fs,
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                                int highpass)
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{
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    int unstable;
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    float c, cfreq, w0, k1, k2;
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    if (!highpass) {
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        c = (1.0f/sqrtf(sqrtf(pow(2.0f, 1.0f/n) - 3.0f/4.0f) - 0.5f))/sqrtf(3.0f);
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        cfreq = c*f0/fs;
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        unstable = (cfreq <= 0.0f || cfreq >= 1.0f/4.0f);
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    } else {
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        c = sqrtf(3.0f)*sqrtf(sqrtf(pow(2.0f, 1.0f/n) - 3.0f/4.0f) - 0.5f);
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        cfreq = 0.5f - c*f0/fs;
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        unstable = (cfreq <= 3.0f/8.0f || cfreq >= 1.0f/2.0f);
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    }
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    w0 = tanf(M_PI*cfreq);
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    k1 = 3.0f * w0;
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    k2 = 3.0f * w0;
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    s->a[0] = k2/(1.0f + k1 + k2);
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    s->a[1] = 2.0f * s->a[0];
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    s->a[2] = s->a[0];
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    s->b[0] = 2.0f * s->a[0] * (1.0f/k2 - 1.0f);
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    s->b[1] = 1.0f - (s->a[0] + s->a[1] + s->a[2] + s->b[0]);
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    if (highpass) {
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        s->a[1] *= -1;
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        s->b[0] *= -1;
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    }
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    return unstable;
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}
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static inline int bessel_init(FFBesselFilter *s, float n, float f0, float fs,
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                              int highpass)
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{
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    memset(s, 0, sizeof(FFBesselFilter));
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    return bessel_reinit(s, n, f0, fs, highpass);
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}
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static inline float bessel_filter(FFBesselFilter *s, float x)
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{
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    s->x[2] = s->x[1];
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    s->x[1] = s->x[0];
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    s->x[0] = x;
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    s->y[2] = s->y[1];
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    s->y[1] = s->y[0];
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    s->y[0] = s->a[0]*s->x[0] + s->a[1]*s->x[1] + s->a[2]*s->x[2] + s->b[0]*s->y[1] + s->b[1]*s->y[2];
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    return s->y[0];
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}
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#endif /* AVCODEC_OPUSENC_UTILS_H */