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annotate src/opus-1.3/silk/LP_variable_cutoff.c @ 79:91c729825bca pa_catalina

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Update build for AUDIO_COMPONENT_FIX
author Chris Cannam
date Wed, 30 Oct 2019 12:40:34 +0000
parents 7aeed7906520
children
rev   line source
Chris@69 1 /***********************************************************************
Chris@69 2 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
Chris@69 3 Redistribution and use in source and binary forms, with or without
Chris@69 4 modification, are permitted provided that the following conditions
Chris@69 5 are met:
Chris@69 6 - Redistributions of source code must retain the above copyright notice,
Chris@69 7 this list of conditions and the following disclaimer.
Chris@69 8 - Redistributions in binary form must reproduce the above copyright
Chris@69 9 notice, this list of conditions and the following disclaimer in the
Chris@69 10 documentation and/or other materials provided with the distribution.
Chris@69 11 - Neither the name of Internet Society, IETF or IETF Trust, nor the
Chris@69 12 names of specific contributors, may be used to endorse or promote
Chris@69 13 products derived from this software without specific prior written
Chris@69 14 permission.
Chris@69 15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
Chris@69 16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
Chris@69 17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
Chris@69 18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
Chris@69 19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
Chris@69 20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
Chris@69 21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
Chris@69 22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
Chris@69 23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
Chris@69 24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
Chris@69 25 POSSIBILITY OF SUCH DAMAGE.
Chris@69 26 ***********************************************************************/
Chris@69 27
Chris@69 28 #ifdef HAVE_CONFIG_H
Chris@69 29 #include "config.h"
Chris@69 30 #endif
Chris@69 31
Chris@69 32 /*
Chris@69 33 Elliptic/Cauer filters designed with 0.1 dB passband ripple,
Chris@69 34 80 dB minimum stopband attenuation, and
Chris@69 35 [0.95 : 0.15 : 0.35] normalized cut off frequencies.
Chris@69 36 */
Chris@69 37
Chris@69 38 #include "main.h"
Chris@69 39
Chris@69 40 /* Helper function, interpolates the filter taps */
Chris@69 41 static OPUS_INLINE void silk_LP_interpolate_filter_taps(
Chris@69 42 opus_int32 B_Q28[ TRANSITION_NB ],
Chris@69 43 opus_int32 A_Q28[ TRANSITION_NA ],
Chris@69 44 const opus_int ind,
Chris@69 45 const opus_int32 fac_Q16
Chris@69 46 )
Chris@69 47 {
Chris@69 48 opus_int nb, na;
Chris@69 49
Chris@69 50 if( ind < TRANSITION_INT_NUM - 1 ) {
Chris@69 51 if( fac_Q16 > 0 ) {
Chris@69 52 if( fac_Q16 < 32768 ) { /* fac_Q16 is in range of a 16-bit int */
Chris@69 53 /* Piece-wise linear interpolation of B and A */
Chris@69 54 for( nb = 0; nb < TRANSITION_NB; nb++ ) {
Chris@69 55 B_Q28[ nb ] = silk_SMLAWB(
Chris@69 56 silk_Transition_LP_B_Q28[ ind ][ nb ],
Chris@69 57 silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] -
Chris@69 58 silk_Transition_LP_B_Q28[ ind ][ nb ],
Chris@69 59 fac_Q16 );
Chris@69 60 }
Chris@69 61 for( na = 0; na < TRANSITION_NA; na++ ) {
Chris@69 62 A_Q28[ na ] = silk_SMLAWB(
Chris@69 63 silk_Transition_LP_A_Q28[ ind ][ na ],
Chris@69 64 silk_Transition_LP_A_Q28[ ind + 1 ][ na ] -
Chris@69 65 silk_Transition_LP_A_Q28[ ind ][ na ],
Chris@69 66 fac_Q16 );
Chris@69 67 }
Chris@69 68 } else { /* ( fac_Q16 - ( 1 << 16 ) ) is in range of a 16-bit int */
Chris@69 69 silk_assert( fac_Q16 - ( 1 << 16 ) == silk_SAT16( fac_Q16 - ( 1 << 16 ) ) );
Chris@69 70 /* Piece-wise linear interpolation of B and A */
Chris@69 71 for( nb = 0; nb < TRANSITION_NB; nb++ ) {
Chris@69 72 B_Q28[ nb ] = silk_SMLAWB(
Chris@69 73 silk_Transition_LP_B_Q28[ ind + 1 ][ nb ],
Chris@69 74 silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] -
Chris@69 75 silk_Transition_LP_B_Q28[ ind ][ nb ],
Chris@69 76 fac_Q16 - ( (opus_int32)1 << 16 ) );
Chris@69 77 }
Chris@69 78 for( na = 0; na < TRANSITION_NA; na++ ) {
Chris@69 79 A_Q28[ na ] = silk_SMLAWB(
Chris@69 80 silk_Transition_LP_A_Q28[ ind + 1 ][ na ],
Chris@69 81 silk_Transition_LP_A_Q28[ ind + 1 ][ na ] -
Chris@69 82 silk_Transition_LP_A_Q28[ ind ][ na ],
Chris@69 83 fac_Q16 - ( (opus_int32)1 << 16 ) );
Chris@69 84 }
Chris@69 85 }
Chris@69 86 } else {
Chris@69 87 silk_memcpy( B_Q28, silk_Transition_LP_B_Q28[ ind ], TRANSITION_NB * sizeof( opus_int32 ) );
Chris@69 88 silk_memcpy( A_Q28, silk_Transition_LP_A_Q28[ ind ], TRANSITION_NA * sizeof( opus_int32 ) );
Chris@69 89 }
Chris@69 90 } else {
Chris@69 91 silk_memcpy( B_Q28, silk_Transition_LP_B_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NB * sizeof( opus_int32 ) );
Chris@69 92 silk_memcpy( A_Q28, silk_Transition_LP_A_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NA * sizeof( opus_int32 ) );
Chris@69 93 }
Chris@69 94 }
Chris@69 95
Chris@69 96 /* Low-pass filter with variable cutoff frequency based on */
Chris@69 97 /* piece-wise linear interpolation between elliptic filters */
Chris@69 98 /* Start by setting psEncC->mode <> 0; */
Chris@69 99 /* Deactivate by setting psEncC->mode = 0; */
Chris@69 100 void silk_LP_variable_cutoff(
Chris@69 101 silk_LP_state *psLP, /* I/O LP filter state */
Chris@69 102 opus_int16 *frame, /* I/O Low-pass filtered output signal */
Chris@69 103 const opus_int frame_length /* I Frame length */
Chris@69 104 )
Chris@69 105 {
Chris@69 106 opus_int32 B_Q28[ TRANSITION_NB ], A_Q28[ TRANSITION_NA ], fac_Q16 = 0;
Chris@69 107 opus_int ind = 0;
Chris@69 108
Chris@69 109 silk_assert( psLP->transition_frame_no >= 0 && psLP->transition_frame_no <= TRANSITION_FRAMES );
Chris@69 110
Chris@69 111 /* Run filter if needed */
Chris@69 112 if( psLP->mode != 0 ) {
Chris@69 113 /* Calculate index and interpolation factor for interpolation */
Chris@69 114 #if( TRANSITION_INT_STEPS == 64 )
Chris@69 115 fac_Q16 = silk_LSHIFT( TRANSITION_FRAMES - psLP->transition_frame_no, 16 - 6 );
Chris@69 116 #else
Chris@69 117 fac_Q16 = silk_DIV32_16( silk_LSHIFT( TRANSITION_FRAMES - psLP->transition_frame_no, 16 ), TRANSITION_FRAMES );
Chris@69 118 #endif
Chris@69 119 ind = silk_RSHIFT( fac_Q16, 16 );
Chris@69 120 fac_Q16 -= silk_LSHIFT( ind, 16 );
Chris@69 121
Chris@69 122 silk_assert( ind >= 0 );
Chris@69 123 silk_assert( ind < TRANSITION_INT_NUM );
Chris@69 124
Chris@69 125 /* Interpolate filter coefficients */
Chris@69 126 silk_LP_interpolate_filter_taps( B_Q28, A_Q28, ind, fac_Q16 );
Chris@69 127
Chris@69 128 /* Update transition frame number for next frame */
Chris@69 129 psLP->transition_frame_no = silk_LIMIT( psLP->transition_frame_no + psLP->mode, 0, TRANSITION_FRAMES );
Chris@69 130
Chris@69 131 /* ARMA low-pass filtering */
Chris@69 132 silk_assert( TRANSITION_NB == 3 && TRANSITION_NA == 2 );
Chris@69 133 silk_biquad_alt_stride1( frame, B_Q28, A_Q28, psLP->In_LP_State, frame, frame_length);
Chris@69 134 }
Chris@69 135 }