d9a291f641
Took the opportunity to undo the Godot changed made to the opus source. The opus module should eventually be built in its own environment to avoid polluting others with too many include dirs and defines. TODO: Fix the platform/ stuff for opus.
136 lines
6.4 KiB
C
136 lines
6.4 KiB
C
/***********************************************************************
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Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of Internet Society, IETF or IETF Trust, nor the
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names of specific contributors, may be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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***********************************************************************/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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/*
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Elliptic/Cauer filters designed with 0.1 dB passband ripple,
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80 dB minimum stopband attenuation, and
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[0.95 : 0.15 : 0.35] normalized cut off frequencies.
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*/
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#include "main.h"
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/* Helper function, interpolates the filter taps */
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static OPUS_INLINE void silk_LP_interpolate_filter_taps(
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opus_int32 B_Q28[ TRANSITION_NB ],
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opus_int32 A_Q28[ TRANSITION_NA ],
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const opus_int ind,
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const opus_int32 fac_Q16
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)
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{
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opus_int nb, na;
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if( ind < TRANSITION_INT_NUM - 1 ) {
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if( fac_Q16 > 0 ) {
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if( fac_Q16 < 32768 ) { /* fac_Q16 is in range of a 16-bit int */
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/* Piece-wise linear interpolation of B and A */
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for( nb = 0; nb < TRANSITION_NB; nb++ ) {
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B_Q28[ nb ] = silk_SMLAWB(
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silk_Transition_LP_B_Q28[ ind ][ nb ],
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silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] -
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silk_Transition_LP_B_Q28[ ind ][ nb ],
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fac_Q16 );
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}
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for( na = 0; na < TRANSITION_NA; na++ ) {
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A_Q28[ na ] = silk_SMLAWB(
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silk_Transition_LP_A_Q28[ ind ][ na ],
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silk_Transition_LP_A_Q28[ ind + 1 ][ na ] -
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silk_Transition_LP_A_Q28[ ind ][ na ],
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fac_Q16 );
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}
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} else { /* ( fac_Q16 - ( 1 << 16 ) ) is in range of a 16-bit int */
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silk_assert( fac_Q16 - ( 1 << 16 ) == silk_SAT16( fac_Q16 - ( 1 << 16 ) ) );
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/* Piece-wise linear interpolation of B and A */
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for( nb = 0; nb < TRANSITION_NB; nb++ ) {
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B_Q28[ nb ] = silk_SMLAWB(
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silk_Transition_LP_B_Q28[ ind + 1 ][ nb ],
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silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] -
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silk_Transition_LP_B_Q28[ ind ][ nb ],
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fac_Q16 - ( (opus_int32)1 << 16 ) );
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}
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for( na = 0; na < TRANSITION_NA; na++ ) {
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A_Q28[ na ] = silk_SMLAWB(
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silk_Transition_LP_A_Q28[ ind + 1 ][ na ],
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silk_Transition_LP_A_Q28[ ind + 1 ][ na ] -
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silk_Transition_LP_A_Q28[ ind ][ na ],
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fac_Q16 - ( (opus_int32)1 << 16 ) );
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}
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}
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} else {
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silk_memcpy( B_Q28, silk_Transition_LP_B_Q28[ ind ], TRANSITION_NB * sizeof( opus_int32 ) );
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silk_memcpy( A_Q28, silk_Transition_LP_A_Q28[ ind ], TRANSITION_NA * sizeof( opus_int32 ) );
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}
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} else {
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silk_memcpy( B_Q28, silk_Transition_LP_B_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NB * sizeof( opus_int32 ) );
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silk_memcpy( A_Q28, silk_Transition_LP_A_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NA * sizeof( opus_int32 ) );
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}
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}
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/* Low-pass filter with variable cutoff frequency based on */
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/* piece-wise linear interpolation between elliptic filters */
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/* Start by setting psEncC->mode <> 0; */
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/* Deactivate by setting psEncC->mode = 0; */
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void silk_LP_variable_cutoff(
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silk_LP_state *psLP, /* I/O LP filter state */
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opus_int16 *frame, /* I/O Low-pass filtered output signal */
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const opus_int frame_length /* I Frame length */
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)
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{
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opus_int32 B_Q28[ TRANSITION_NB ], A_Q28[ TRANSITION_NA ], fac_Q16 = 0;
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opus_int ind = 0;
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silk_assert( psLP->transition_frame_no >= 0 && psLP->transition_frame_no <= TRANSITION_FRAMES );
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/* Run filter if needed */
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if( psLP->mode != 0 ) {
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/* Calculate index and interpolation factor for interpolation */
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#if( TRANSITION_INT_STEPS == 64 )
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fac_Q16 = silk_LSHIFT( TRANSITION_FRAMES - psLP->transition_frame_no, 16 - 6 );
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#else
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fac_Q16 = silk_DIV32_16( silk_LSHIFT( TRANSITION_FRAMES - psLP->transition_frame_no, 16 ), TRANSITION_FRAMES );
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#endif
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ind = silk_RSHIFT( fac_Q16, 16 );
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fac_Q16 -= silk_LSHIFT( ind, 16 );
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silk_assert( ind >= 0 );
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silk_assert( ind < TRANSITION_INT_NUM );
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/* Interpolate filter coefficients */
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silk_LP_interpolate_filter_taps( B_Q28, A_Q28, ind, fac_Q16 );
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/* Update transition frame number for next frame */
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psLP->transition_frame_no = silk_LIMIT( psLP->transition_frame_no + psLP->mode, 0, TRANSITION_FRAMES );
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/* ARMA low-pass filtering */
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silk_assert( TRANSITION_NB == 3 && TRANSITION_NA == 2 );
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silk_biquad_alt( frame, B_Q28, A_Q28, psLP->In_LP_State, frame, frame_length, 1);
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}
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}
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