101 lines
4.8 KiB
C
101 lines
4.8 KiB
C
/***********************************************************************
|
|
Copyright (c) 2006-2011, Skype Limited. All rights reserved.
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions
|
|
are met:
|
|
- Redistributions of source code must retain the above copyright notice,
|
|
this list of conditions and the following disclaimer.
|
|
- Redistributions in binary form must reproduce the above copyright
|
|
notice, this list of conditions and the following disclaimer in the
|
|
documentation and/or other materials provided with the distribution.
|
|
- Neither the name of Internet Society, IETF or IETF Trust, nor the
|
|
names of specific contributors, may be used to endorse or promote
|
|
products derived from this software without specific prior written
|
|
permission.
|
|
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
|
|
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
POSSIBILITY OF SUCH DAMAGE.
|
|
***********************************************************************/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config.h"
|
|
#endif
|
|
|
|
#include "SigProc_FIX.h"
|
|
|
|
/* Apply sine window to signal vector. */
|
|
/* Window types: */
|
|
/* 1 -> sine window from 0 to pi/2 */
|
|
/* 2 -> sine window from pi/2 to pi */
|
|
/* Every other sample is linearly interpolated, for speed. */
|
|
/* Window length must be between 16 and 120 (incl) and a multiple of 4. */
|
|
|
|
/* Matlab code for table:
|
|
for k=16:9*4:16+2*9*4, fprintf(' %7.d,', -round(65536*pi ./ (k:4:k+8*4))); fprintf('\n'); end
|
|
*/
|
|
static const opus_int16 freq_table_Q16[ 27 ] = {
|
|
12111, 9804, 8235, 7100, 6239, 5565, 5022, 4575, 4202,
|
|
3885, 3612, 3375, 3167, 2984, 2820, 2674, 2542, 2422,
|
|
2313, 2214, 2123, 2038, 1961, 1889, 1822, 1760, 1702,
|
|
};
|
|
|
|
void silk_apply_sine_window(
|
|
opus_int16 px_win[], /* O Pointer to windowed signal */
|
|
const opus_int16 px[], /* I Pointer to input signal */
|
|
const opus_int win_type, /* I Selects a window type */
|
|
const opus_int length /* I Window length, multiple of 4 */
|
|
)
|
|
{
|
|
opus_int k, f_Q16, c_Q16;
|
|
opus_int32 S0_Q16, S1_Q16;
|
|
|
|
celt_assert( win_type == 1 || win_type == 2 );
|
|
|
|
/* Length must be in a range from 16 to 120 and a multiple of 4 */
|
|
celt_assert( length >= 16 && length <= 120 );
|
|
celt_assert( ( length & 3 ) == 0 );
|
|
|
|
/* Frequency */
|
|
k = ( length >> 2 ) - 4;
|
|
celt_assert( k >= 0 && k <= 26 );
|
|
f_Q16 = (opus_int)freq_table_Q16[ k ];
|
|
|
|
/* Factor used for cosine approximation */
|
|
c_Q16 = silk_SMULWB( (opus_int32)f_Q16, -f_Q16 );
|
|
silk_assert( c_Q16 >= -32768 );
|
|
|
|
/* initialize state */
|
|
if( win_type == 1 ) {
|
|
/* start from 0 */
|
|
S0_Q16 = 0;
|
|
/* approximation of sin(f) */
|
|
S1_Q16 = f_Q16 + silk_RSHIFT( length, 3 );
|
|
} else {
|
|
/* start from 1 */
|
|
S0_Q16 = ( (opus_int32)1 << 16 );
|
|
/* approximation of cos(f) */
|
|
S1_Q16 = ( (opus_int32)1 << 16 ) + silk_RSHIFT( c_Q16, 1 ) + silk_RSHIFT( length, 4 );
|
|
}
|
|
|
|
/* Uses the recursive equation: sin(n*f) = 2 * cos(f) * sin((n-1)*f) - sin((n-2)*f) */
|
|
/* 4 samples at a time */
|
|
for( k = 0; k < length; k += 4 ) {
|
|
px_win[ k ] = (opus_int16)silk_SMULWB( silk_RSHIFT( S0_Q16 + S1_Q16, 1 ), px[ k ] );
|
|
px_win[ k + 1 ] = (opus_int16)silk_SMULWB( S1_Q16, px[ k + 1] );
|
|
S0_Q16 = silk_SMULWB( S1_Q16, c_Q16 ) + silk_LSHIFT( S1_Q16, 1 ) - S0_Q16 + 1;
|
|
S0_Q16 = silk_min( S0_Q16, ( (opus_int32)1 << 16 ) );
|
|
|
|
px_win[ k + 2 ] = (opus_int16)silk_SMULWB( silk_RSHIFT( S0_Q16 + S1_Q16, 1 ), px[ k + 2] );
|
|
px_win[ k + 3 ] = (opus_int16)silk_SMULWB( S0_Q16, px[ k + 3 ] );
|
|
S1_Q16 = silk_SMULWB( S0_Q16, c_Q16 ) + silk_LSHIFT( S0_Q16, 1 ) - S1_Q16;
|
|
S1_Q16 = silk_min( S1_Q16, ( (opus_int32)1 << 16 ) );
|
|
}
|
|
}
|