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| Rev | Author | Line No. | Line |
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| 4349 | Serge | 1 | /* |
| 2 | * G.729, G729 Annex D postfilter |
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| 3 | * Copyright (c) 2008 Vladimir Voroshilov |
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| 4 | * |
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| 5 | * This file is part of FFmpeg. |
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| 6 | * |
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| 7 | * FFmpeg is free software; you can redistribute it and/or |
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| 8 | * modify it under the terms of the GNU Lesser General Public |
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| 9 | * License as published by the Free Software Foundation; either |
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| 10 | * version 2.1 of the License, or (at your option) any later version. |
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| 11 | * |
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| 12 | * FFmpeg is distributed in the hope that it will be useful, |
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 15 | * Lesser General Public License for more details. |
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| 16 | * |
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| 17 | * You should have received a copy of the GNU Lesser General Public |
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| 18 | * License along with FFmpeg; if not, write to the Free Software |
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| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 20 | */ |
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| 21 | #ifndef FFMPEG_G729POSTFILTER_H |
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| 22 | #define FFMPEG_G729POSTFILTER_H |
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| 23 | |||
| 24 | #include |
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| 25 | #include "dsputil.h" |
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| 26 | |||
| 27 | /** |
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| 28 | * tilt compensation factor (G.729, k1>0) |
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| 29 | * 0.2 in Q15 |
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| 30 | */ |
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| 31 | #define G729_TILT_FACTOR_PLUS 6554 |
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| 32 | |||
| 33 | /** |
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| 34 | * tilt compensation factor (G.729, k1<0) |
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| 35 | * 0.9 in Q15 |
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| 36 | */ |
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| 37 | #define G729_TILT_FACTOR_MINUS 29491 |
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| 38 | |||
| 39 | /* 4.2.2 */ |
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| 40 | #define FORMANT_PP_FACTOR_NUM 18022 //0.55 in Q15 |
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| 41 | #define FORMANT_PP_FACTOR_DEN 22938 //0.70 in Q15 |
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| 42 | |||
| 43 | /** |
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| 44 | * gain adjustment factor (G.729, 4.2.4) |
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| 45 | * 0.9875 in Q15 |
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| 46 | */ |
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| 47 | #define G729_AGC_FACTOR 32358 |
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| 48 | #define G729_AGC_FAC1 (32768-G729_AGC_FACTOR) |
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| 49 | |||
| 50 | /** |
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| 51 | * 1.0 / (1.0 + 0.5) in Q15 |
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| 52 | * where 0.5 is the minimum value of |
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| 53 | * weight factor, controlling amount of long-term postfiltering |
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| 54 | */ |
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| 55 | #define MIN_LT_FILT_FACTOR_A 21845 |
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| 56 | |||
| 57 | /** |
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| 58 | * Short interpolation filter length |
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| 59 | */ |
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| 60 | #define SHORT_INT_FILT_LEN 2 |
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| 61 | |||
| 62 | /** |
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| 63 | * Long interpolation filter length |
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| 64 | */ |
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| 65 | #define LONG_INT_FILT_LEN 8 |
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| 66 | |||
| 67 | /** |
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| 68 | * Number of analyzed fractional pitch delays in second stage of long-term |
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| 69 | * postfilter |
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| 70 | */ |
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| 71 | #define ANALYZED_FRAC_DELAYS 7 |
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| 72 | |||
| 73 | /** |
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| 74 | * Amount of past residual signal data stored in buffer |
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| 75 | */ |
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| 76 | #define RES_PREV_DATA_SIZE (PITCH_DELAY_MAX + LONG_INT_FILT_LEN + 1) |
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| 77 | |||
| 78 | /** |
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| 79 | * \brief Signal postfiltering (4.2) |
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| 80 | * \param dsp initialized DSP context |
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| 81 | * \param ht_prev_data [in/out] (Q12) pointer to variable receiving tilt |
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| 82 | * compensation filter data from previous subframe |
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| 83 | * \param voicing [in/out] (Q0) pointer to variable receiving voicing decision |
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| 84 | * \param lp_filter_coeffs (Q12) LP filter coefficients |
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| 85 | * \param pitch_delay_int integer part of the pitch delay |
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| 86 | * \param residual [in/out] (Q0) residual signal buffer (used in long-term postfilter) |
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| 87 | * \param res_filter_data [in/out] (Q0) speech data of previous subframe |
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| 88 | * \param pos_filter_data [in/out] (Q0) previous speech data for short-term postfilter |
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| 89 | * \param speech [in/out] (Q0) signal buffer |
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| 90 | * \param subframe_size size of subframe |
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| 91 | * |
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| 92 | * Filtering has the following stages: |
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| 93 | * Long-term postfilter (4.2.1) |
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| 94 | * Short-term postfilter (4.2.2). |
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| 95 | * Tilt-compensation (4.2.3) |
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| 96 | */ |
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| 97 | void ff_g729_postfilter(DSPContext *dsp, int16_t* ht_prev_data, int* voicing, |
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| 98 | const int16_t *lp_filter_coeffs, int pitch_delay_int, |
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| 99 | int16_t* residual, int16_t* res_filter_data, |
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| 100 | int16_t* pos_filter_data, int16_t *speech, |
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| 101 | int subframe_size); |
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| 102 | |||
| 103 | /** |
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| 104 | * \brief Adaptive gain control (4.2.4) |
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| 105 | * \param gain_before (Q0) gain of speech before applying postfilters |
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| 106 | * \param gain_after (Q0) gain of speech after applying postfilters |
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| 107 | * \param speech [in/out] (Q0) signal buffer |
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| 108 | * \param subframe_size length of subframe |
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| 109 | * \param gain_prev (Q12) previous value of gain coefficient |
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| 110 | * |
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| 111 | * \return (Q12) last value of gain coefficient |
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| 112 | */ |
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| 113 | int16_t ff_g729_adaptive_gain_control(int gain_before, int gain_after, int16_t *speech, |
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| 114 | int subframe_size, int16_t gain_prev); |
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| 115 | |||
| 116 | #endif // FFMPEG_G729POSTFILTER_H |