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comparison: media/libopus/silk/LP_variable_cutoff.c
media/libopus/silk/LP_variable_cutoff.c
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- TOR_BUG_9701
- changeset 15
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| -1:000000000000 | 0:a25da30273a5 |
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| 1 /*********************************************************************** | |
| 2 Copyright (c) 2006-2011, Skype Limited. All rights reserved. | |
| 3 Redistribution and use in source and binary forms, with or without | |
| 4 modification, are permitted provided that the following conditions | |
| 5 are met: | |
| 6 - Redistributions of source code must retain the above copyright notice, | |
| 7 this list of conditions and the following disclaimer. | |
| 8 - Redistributions in binary form must reproduce the above copyright | |
| 9 notice, this list of conditions and the following disclaimer in the | |
| 10 documentation and/or other materials provided with the distribution. | |
| 11 - Neither the name of Internet Society, IETF or IETF Trust, nor the | |
| 12 names of specific contributors, may be used to endorse or promote | |
| 13 products derived from this software without specific prior written | |
| 14 permission. | |
| 15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | |
| 19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 25 POSSIBILITY OF SUCH DAMAGE. | |
| 26 ***********************************************************************/ | |
| 27 | |
| 28 #ifdef HAVE_CONFIG_H | |
| 29 #include "config.h" | |
| 30 #endif | |
| 31 | |
| 32 /* | |
| 33 Elliptic/Cauer filters designed with 0.1 dB passband ripple, | |
| 34 80 dB minimum stopband attenuation, and | |
| 35 [0.95 : 0.15 : 0.35] normalized cut off frequencies. | |
| 36 */ | |
| 37 | |
| 38 #include "main.h" | |
| 39 | |
| 40 /* Helper function, interpolates the filter taps */ | |
| 41 static OPUS_INLINE void silk_LP_interpolate_filter_taps( | |
| 42 opus_int32 B_Q28[ TRANSITION_NB ], | |
| 43 opus_int32 A_Q28[ TRANSITION_NA ], | |
| 44 const opus_int ind, | |
| 45 const opus_int32 fac_Q16 | |
| 46 ) | |
| 47 { | |
| 48 opus_int nb, na; | |
| 49 | |
| 50 if( ind < TRANSITION_INT_NUM - 1 ) { | |
| 51 if( fac_Q16 > 0 ) { | |
| 52 if( fac_Q16 < 32768 ) { /* fac_Q16 is in range of a 16-bit int */ | |
| 53 /* Piece-wise linear interpolation of B and A */ | |
| 54 for( nb = 0; nb < TRANSITION_NB; nb++ ) { | |
| 55 B_Q28[ nb ] = silk_SMLAWB( | |
| 56 silk_Transition_LP_B_Q28[ ind ][ nb ], | |
| 57 silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] - | |
| 58 silk_Transition_LP_B_Q28[ ind ][ nb ], | |
| 59 fac_Q16 ); | |
| 60 } | |
| 61 for( na = 0; na < TRANSITION_NA; na++ ) { | |
| 62 A_Q28[ na ] = silk_SMLAWB( | |
| 63 silk_Transition_LP_A_Q28[ ind ][ na ], | |
| 64 silk_Transition_LP_A_Q28[ ind + 1 ][ na ] - | |
| 65 silk_Transition_LP_A_Q28[ ind ][ na ], | |
| 66 fac_Q16 ); | |
| 67 } | |
| 68 } else { /* ( fac_Q16 - ( 1 << 16 ) ) is in range of a 16-bit int */ | |
| 69 silk_assert( fac_Q16 - ( 1 << 16 ) == silk_SAT16( fac_Q16 - ( 1 << 16 ) ) ); | |
| 70 /* Piece-wise linear interpolation of B and A */ | |
| 71 for( nb = 0; nb < TRANSITION_NB; nb++ ) { | |
| 72 B_Q28[ nb ] = silk_SMLAWB( | |
| 73 silk_Transition_LP_B_Q28[ ind + 1 ][ nb ], | |
| 74 silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] - | |
| 75 silk_Transition_LP_B_Q28[ ind ][ nb ], | |
| 76 fac_Q16 - ( (opus_int32)1 << 16 ) ); | |
| 77 } | |
| 78 for( na = 0; na < TRANSITION_NA; na++ ) { | |
| 79 A_Q28[ na ] = silk_SMLAWB( | |
| 80 silk_Transition_LP_A_Q28[ ind + 1 ][ na ], | |
| 81 silk_Transition_LP_A_Q28[ ind + 1 ][ na ] - | |
| 82 silk_Transition_LP_A_Q28[ ind ][ na ], | |
| 83 fac_Q16 - ( (opus_int32)1 << 16 ) ); | |
| 84 } | |
| 85 } | |
| 86 } else { | |
| 87 silk_memcpy( B_Q28, silk_Transition_LP_B_Q28[ ind ], TRANSITION_NB * sizeof( opus_int32 ) ); | |
| 88 silk_memcpy( A_Q28, silk_Transition_LP_A_Q28[ ind ], TRANSITION_NA * sizeof( opus_int32 ) ); | |
| 89 } | |
| 90 } else { | |
| 91 silk_memcpy( B_Q28, silk_Transition_LP_B_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NB * sizeof( opus_int32 ) ); | |
| 92 silk_memcpy( A_Q28, silk_Transition_LP_A_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NA * sizeof( opus_int32 ) ); | |
| 93 } | |
| 94 } | |
| 95 | |
| 96 /* Low-pass filter with variable cutoff frequency based on */ | |
| 97 /* piece-wise linear interpolation between elliptic filters */ | |
| 98 /* Start by setting psEncC->mode <> 0; */ | |
| 99 /* Deactivate by setting psEncC->mode = 0; */ | |
| 100 void silk_LP_variable_cutoff( | |
| 101 silk_LP_state *psLP, /* I/O LP filter state */ | |
| 102 opus_int16 *frame, /* I/O Low-pass filtered output signal */ | |
| 103 const opus_int frame_length /* I Frame length */ | |
| 104 ) | |
| 105 { | |
| 106 opus_int32 B_Q28[ TRANSITION_NB ], A_Q28[ TRANSITION_NA ], fac_Q16 = 0; | |
| 107 opus_int ind = 0; | |
| 108 | |
| 109 silk_assert( psLP->transition_frame_no >= 0 && psLP->transition_frame_no <= TRANSITION_FRAMES ); | |
| 110 | |
| 111 /* Run filter if needed */ | |
| 112 if( psLP->mode != 0 ) { | |
| 113 /* Calculate index and interpolation factor for interpolation */ | |
| 114 #if( TRANSITION_INT_STEPS == 64 ) | |
| 115 fac_Q16 = silk_LSHIFT( TRANSITION_FRAMES - psLP->transition_frame_no, 16 - 6 ); | |
| 116 #else | |
| 117 fac_Q16 = silk_DIV32_16( silk_LSHIFT( TRANSITION_FRAMES - psLP->transition_frame_no, 16 ), TRANSITION_FRAMES ); | |
| 118 #endif | |
| 119 ind = silk_RSHIFT( fac_Q16, 16 ); | |
| 120 fac_Q16 -= silk_LSHIFT( ind, 16 ); | |
| 121 | |
| 122 silk_assert( ind >= 0 ); | |
| 123 silk_assert( ind < TRANSITION_INT_NUM ); | |
| 124 | |
| 125 /* Interpolate filter coefficients */ | |
| 126 silk_LP_interpolate_filter_taps( B_Q28, A_Q28, ind, fac_Q16 ); | |
| 127 | |
| 128 /* Update transition frame number for next frame */ | |
| 129 psLP->transition_frame_no = silk_LIMIT( psLP->transition_frame_no + psLP->mode, 0, TRANSITION_FRAMES ); | |
| 130 | |
| 131 /* ARMA low-pass filtering */ | |
| 132 silk_assert( TRANSITION_NB == 3 && TRANSITION_NA == 2 ); | |
| 133 silk_biquad_alt( frame, B_Q28, A_Q28, psLP->In_LP_State, frame, frame_length, 1); | |
| 134 } | |
| 135 } |
