LCOV - code coverage report
Current view: top level - libavcodec - opusenc_utils.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 0 31 0.0 %
Date: 2017-12-18 20:14:19 Functions: 0 3 0.0 %

          Line data    Source code
       1             : /*
       2             :  * Opus encoder
       3             :  * Copyright (c) 2017 Rostislav Pehlivanov <atomnuker@gmail.com>
       4             :  *
       5             :  * This file is part of FFmpeg.
       6             :  *
       7             :  * FFmpeg is free software; you can redistribute it and/or
       8             :  * modify it under the terms of the GNU Lesser General Public
       9             :  * License as published by the Free Software Foundation; either
      10             :  * version 2.1 of the License, or (at your option) any later version.
      11             :  *
      12             :  * FFmpeg is distributed in the hope that it will be useful,
      13             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      14             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      15             :  * Lesser General Public License for more details.
      16             :  *
      17             :  * You should have received a copy of the GNU Lesser General Public
      18             :  * License along with FFmpeg; if not, write to the Free Software
      19             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      20             :  */
      21             : 
      22             : #ifndef AVCODEC_OPUSENC_UTILS_H
      23             : #define AVCODEC_OPUSENC_UTILS_H
      24             : 
      25             : #include "opus.h"
      26             : 
      27             : typedef struct FFBesselFilter {
      28             :     float a[3];
      29             :     float b[2];
      30             :     float x[3];
      31             :     float y[3];
      32             : } FFBesselFilter;
      33             : 
      34             : /* Fills the coefficients, returns 1 if filter will be unstable */
      35           0 : static inline int bessel_reinit(FFBesselFilter *s, float n, float f0, float fs,
      36             :                                 int highpass)
      37             : {
      38             :     int unstable;
      39             :     float c, cfreq, w0, k1, k2;
      40             : 
      41           0 :     if (!highpass) {
      42           0 :         c = (1.0f/sqrtf(sqrtf(pow(2.0f, 1.0f/n) - 3.0f/4.0f) - 0.5f))/sqrtf(3.0f);
      43           0 :         cfreq = c*f0/fs;
      44           0 :         unstable = (cfreq <= 0.0f || cfreq >= 1.0f/4.0f);
      45             :     } else {
      46           0 :         c = sqrtf(3.0f)*sqrtf(sqrtf(pow(2.0f, 1.0f/n) - 3.0f/4.0f) - 0.5f);
      47           0 :         cfreq = 0.5f - c*f0/fs;
      48           0 :         unstable = (cfreq <= 3.0f/8.0f || cfreq >= 1.0f/2.0f);
      49             :     }
      50             : 
      51           0 :     w0 = tanf(M_PI*cfreq);
      52           0 :     k1 = 3.0f * w0;
      53           0 :     k2 = 3.0f * w0;
      54             : 
      55           0 :     s->a[0] = k2/(1.0f + k1 + k2);
      56           0 :     s->a[1] = 2.0f * s->a[0];
      57           0 :     s->a[2] = s->a[0];
      58           0 :     s->b[0] = 2.0f * s->a[0] * (1.0f/k2 - 1.0f);
      59           0 :     s->b[1] = 1.0f - (s->a[0] + s->a[1] + s->a[2] + s->b[0]);
      60             : 
      61           0 :     if (highpass) {
      62           0 :         s->a[1] *= -1;
      63           0 :         s->b[0] *= -1;
      64             :     }
      65             : 
      66           0 :     return unstable;
      67             : }
      68             : 
      69           0 : static inline int bessel_init(FFBesselFilter *s, float n, float f0, float fs,
      70             :                               int highpass)
      71             : {
      72           0 :     memset(s, 0, sizeof(FFBesselFilter));
      73           0 :     return bessel_reinit(s, n, f0, fs, highpass);
      74             : }
      75             : 
      76           0 : static inline float bessel_filter(FFBesselFilter *s, float x)
      77             : {
      78           0 :     s->x[2] = s->x[1];
      79           0 :     s->x[1] = s->x[0];
      80           0 :     s->x[0] = x;
      81           0 :     s->y[2] = s->y[1];
      82           0 :     s->y[1] = s->y[0];
      83           0 :     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];
      84           0 :     return s->y[0];
      85             : }
      86             : 
      87             : #endif /* AVCODEC_OPUSENC_UTILS_H */

Generated by: LCOV version 1.13