1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libopus/silk/fixed/apply_sine_window_FIX.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,101 @@
1.4 +/***********************************************************************
1.5 +Copyright (c) 2006-2011, Skype Limited. All rights reserved.
1.6 +Redistribution and use in source and binary forms, with or without
1.7 +modification, are permitted provided that the following conditions
1.8 +are met:
1.9 +- Redistributions of source code must retain the above copyright notice,
1.10 +this list of conditions and the following disclaimer.
1.11 +- Redistributions in binary form must reproduce the above copyright
1.12 +notice, this list of conditions and the following disclaimer in the
1.13 +documentation and/or other materials provided with the distribution.
1.14 +- Neither the name of Internet Society, IETF or IETF Trust, nor the
1.15 +names of specific contributors, may be used to endorse or promote
1.16 +products derived from this software without specific prior written
1.17 +permission.
1.18 +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.19 +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.20 +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.21 +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
1.22 +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.23 +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.24 +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.25 +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.26 +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.27 +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.28 +POSSIBILITY OF SUCH DAMAGE.
1.29 +***********************************************************************/
1.30 +
1.31 +#ifdef HAVE_CONFIG_H
1.32 +#include "config.h"
1.33 +#endif
1.34 +
1.35 +#include "SigProc_FIX.h"
1.36 +
1.37 +/* Apply sine window to signal vector. */
1.38 +/* Window types: */
1.39 +/* 1 -> sine window from 0 to pi/2 */
1.40 +/* 2 -> sine window from pi/2 to pi */
1.41 +/* Every other sample is linearly interpolated, for speed. */
1.42 +/* Window length must be between 16 and 120 (incl) and a multiple of 4. */
1.43 +
1.44 +/* Matlab code for table:
1.45 + for k=16:9*4:16+2*9*4, fprintf(' %7.d,', -round(65536*pi ./ (k:4:k+8*4))); fprintf('\n'); end
1.46 +*/
1.47 +static const opus_int16 freq_table_Q16[ 27 ] = {
1.48 + 12111, 9804, 8235, 7100, 6239, 5565, 5022, 4575, 4202,
1.49 + 3885, 3612, 3375, 3167, 2984, 2820, 2674, 2542, 2422,
1.50 + 2313, 2214, 2123, 2038, 1961, 1889, 1822, 1760, 1702,
1.51 +};
1.52 +
1.53 +void silk_apply_sine_window(
1.54 + opus_int16 px_win[], /* O Pointer to windowed signal */
1.55 + const opus_int16 px[], /* I Pointer to input signal */
1.56 + const opus_int win_type, /* I Selects a window type */
1.57 + const opus_int length /* I Window length, multiple of 4 */
1.58 +)
1.59 +{
1.60 + opus_int k, f_Q16, c_Q16;
1.61 + opus_int32 S0_Q16, S1_Q16;
1.62 +
1.63 + silk_assert( win_type == 1 || win_type == 2 );
1.64 +
1.65 + /* Length must be in a range from 16 to 120 and a multiple of 4 */
1.66 + silk_assert( length >= 16 && length <= 120 );
1.67 + silk_assert( ( length & 3 ) == 0 );
1.68 +
1.69 + /* Frequency */
1.70 + k = ( length >> 2 ) - 4;
1.71 + silk_assert( k >= 0 && k <= 26 );
1.72 + f_Q16 = (opus_int)freq_table_Q16[ k ];
1.73 +
1.74 + /* Factor used for cosine approximation */
1.75 + c_Q16 = silk_SMULWB( (opus_int32)f_Q16, -f_Q16 );
1.76 + silk_assert( c_Q16 >= -32768 );
1.77 +
1.78 + /* initialize state */
1.79 + if( win_type == 1 ) {
1.80 + /* start from 0 */
1.81 + S0_Q16 = 0;
1.82 + /* approximation of sin(f) */
1.83 + S1_Q16 = f_Q16 + silk_RSHIFT( length, 3 );
1.84 + } else {
1.85 + /* start from 1 */
1.86 + S0_Q16 = ( (opus_int32)1 << 16 );
1.87 + /* approximation of cos(f) */
1.88 + S1_Q16 = ( (opus_int32)1 << 16 ) + silk_RSHIFT( c_Q16, 1 ) + silk_RSHIFT( length, 4 );
1.89 + }
1.90 +
1.91 + /* Uses the recursive equation: sin(n*f) = 2 * cos(f) * sin((n-1)*f) - sin((n-2)*f) */
1.92 + /* 4 samples at a time */
1.93 + for( k = 0; k < length; k += 4 ) {
1.94 + px_win[ k ] = (opus_int16)silk_SMULWB( silk_RSHIFT( S0_Q16 + S1_Q16, 1 ), px[ k ] );
1.95 + px_win[ k + 1 ] = (opus_int16)silk_SMULWB( S1_Q16, px[ k + 1] );
1.96 + S0_Q16 = silk_SMULWB( S1_Q16, c_Q16 ) + silk_LSHIFT( S1_Q16, 1 ) - S0_Q16 + 1;
1.97 + S0_Q16 = silk_min( S0_Q16, ( (opus_int32)1 << 16 ) );
1.98 +
1.99 + px_win[ k + 2 ] = (opus_int16)silk_SMULWB( silk_RSHIFT( S0_Q16 + S1_Q16, 1 ), px[ k + 2] );
1.100 + px_win[ k + 3 ] = (opus_int16)silk_SMULWB( S0_Q16, px[ k + 3 ] );
1.101 + S1_Q16 = silk_SMULWB( S0_Q16, c_Q16 ) + silk_LSHIFT( S0_Q16, 1 ) - S1_Q16;
1.102 + S1_Q16 = silk_min( S1_Q16, ( (opus_int32)1 << 16 ) );
1.103 + }
1.104 +}
