repositories / deb_ffmpeg.git / blame
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1 | /* |
| 2 | * G.729, G729 Annex D postfilter | |
| 3 | * Copyright (c) 2008 Vladimir Voroshilov | |
| 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 | #ifndef FFMPEG_G729POSTFILTER_H | |
| 22 | #define FFMPEG_G729POSTFILTER_H | |
| 23 | ||
| 24 | #include <stdint.h> | |
| 25 | #include "audiodsp.h" | |
| 26 | ||
| 27 | /** | |
| 28 | * tilt compensation factor (G.729, k1>0) | |
| 29 | * 0.2 in Q15 | |
| 30 | */ | |
| 31 | #define G729_TILT_FACTOR_PLUS 6554 | |
| 32 | ||
| 33 | /** | |
| 34 | * tilt compensation factor (G.729, k1<0) | |
| 35 | * 0.9 in Q15 | |
| 36 | */ | |
| 37 | #define G729_TILT_FACTOR_MINUS 29491 | |
| 38 | ||
| 39 | /* 4.2.2 */ | |
| 40 | #define FORMANT_PP_FACTOR_NUM 18022 //0.55 in Q15 | |
| 41 | #define FORMANT_PP_FACTOR_DEN 22938 //0.70 in Q15 | |
| 42 | ||
| 43 | /** | |
| 44 | * gain adjustment factor (G.729, 4.2.4) | |
| 45 | * 0.9875 in Q15 | |
| 46 | */ | |
| 47 | #define G729_AGC_FACTOR 32358 | |
| 48 | #define G729_AGC_FAC1 (32768-G729_AGC_FACTOR) | |
| 49 | ||
| 50 | /** | |
| 51 | * 1.0 / (1.0 + 0.5) in Q15 | |
| 52 | * where 0.5 is the minimum value of | |
| 53 | * weight factor, controlling amount of long-term postfiltering | |
| 54 | */ | |
| 55 | #define MIN_LT_FILT_FACTOR_A 21845 | |
| 56 | ||
| 57 | /** | |
| 58 | * Short interpolation filter length | |
| 59 | */ | |
| 60 | #define SHORT_INT_FILT_LEN 2 | |
| 61 | ||
| 62 | /** | |
| 63 | * Long interpolation filter length | |
| 64 | */ | |
| 65 | #define LONG_INT_FILT_LEN 8 | |
| 66 | ||
| 67 | /** | |
| 68 | * Number of analyzed fractional pitch delays in second stage of long-term | |
| 69 | * postfilter | |
| 70 | */ | |
| 71 | #define ANALYZED_FRAC_DELAYS 7 | |
| 72 | ||
| 73 | /** | |
| 74 | * Amount of past residual signal data stored in buffer | |
| 75 | */ | |
| 76 | #define RES_PREV_DATA_SIZE (PITCH_DELAY_MAX + LONG_INT_FILT_LEN + 1) | |
| 77 | ||
| 78 | /** | |
| 79 | * \brief Signal postfiltering (4.2) | |
| 80 | * \param dsp initialized DSP context | |
| 81 | * \param ht_prev_data [in/out] (Q12) pointer to variable receiving tilt | |
| 82 | * compensation filter data from previous subframe | |
| 83 | * \param voicing [in/out] (Q0) pointer to variable receiving voicing decision | |
| 84 | * \param lp_filter_coeffs (Q12) LP filter coefficients | |
| 85 | * \param pitch_delay_int integer part of the pitch delay | |
| 86 | * \param residual [in/out] (Q0) residual signal buffer (used in long-term postfilter) | |
| 87 | * \param res_filter_data [in/out] (Q0) speech data of previous subframe | |
| 88 | * \param pos_filter_data [in/out] (Q0) previous speech data for short-term postfilter | |
| 89 | * \param speech [in/out] (Q0) signal buffer | |
| 90 | * \param subframe_size size of subframe | |
| 91 | * | |
| 92 | * Filtering has the following stages: | |
| 93 | * Long-term postfilter (4.2.1) | |
| 94 | * Short-term postfilter (4.2.2). | |
| 95 | * Tilt-compensation (4.2.3) | |
| 96 | */ | |
| 97 | void ff_g729_postfilter(AudioDSPContext *adsp, int16_t* ht_prev_data, int* voicing, | |
| 98 | const int16_t *lp_filter_coeffs, int pitch_delay_int, | |
| 99 | int16_t* residual, int16_t* res_filter_data, | |
| 100 | int16_t* pos_filter_data, int16_t *speech, | |
| 101 | int subframe_size); | |
| 102 | ||
| 103 | /** | |
| 104 | * \brief Adaptive gain control (4.2.4) | |
| 105 | * \param gain_before (Q0) gain of speech before applying postfilters | |
| 106 | * \param gain_after (Q0) gain of speech after applying postfilters | |
| 107 | * \param speech [in/out] (Q0) signal buffer | |
| 108 | * \param subframe_size length of subframe | |
| 109 | * \param gain_prev (Q12) previous value of gain coefficient | |
| 110 | * | |
| 111 | * \return (Q12) last value of gain coefficient | |
| 112 | */ | |
| 113 | int16_t ff_g729_adaptive_gain_control(int gain_before, int gain_after, int16_t *speech, | |
| 114 | int subframe_size, int16_t gain_prev); | |
| 115 | ||
| 116 | #endif // FFMPEG_G729POSTFILTER_H |