mirror of
https://github.com/DrBeef/ioq3quest.git
synced 2024-11-14 08:31:00 +00:00
75 lines
3.7 KiB
C
75 lines
3.7 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"
|
||
|
|
|
||
|
|
/* Coefficients for 2-band filter bank based on first-order allpass filters */
|
||
|
|
static opus_int16 A_fb1_20 = 5394 << 1;
|
||
|
|
static opus_int16 A_fb1_21 = -24290; /* (opus_int16)(20623 << 1) */
|
||
|
|
|
||
|
|
/* Split signal into two decimated bands using first-order allpass filters */
|
||
|
|
void silk_ana_filt_bank_1(
|
||
|
|
const opus_int16 *in, /* I Input signal [N] */
|
||
|
|
opus_int32 *S, /* I/O State vector [2] */
|
||
|
|
opus_int16 *outL, /* O Low band [N/2] */
|
||
|
|
opus_int16 *outH, /* O High band [N/2] */
|
||
|
|
const opus_int32 N /* I Number of input samples */
|
||
|
|
)
|
||
|
|
{
|
||
|
|
opus_int k, N2 = silk_RSHIFT( N, 1 );
|
||
|
|
opus_int32 in32, X, Y, out_1, out_2;
|
||
|
|
|
||
|
|
/* Internal variables and state are in Q10 format */
|
||
|
|
for( k = 0; k < N2; k++ ) {
|
||
|
|
/* Convert to Q10 */
|
||
|
|
in32 = silk_LSHIFT( (opus_int32)in[ 2 * k ], 10 );
|
||
|
|
|
||
|
|
/* All-pass section for even input sample */
|
||
|
|
Y = silk_SUB32( in32, S[ 0 ] );
|
||
|
|
X = silk_SMLAWB( Y, Y, A_fb1_21 );
|
||
|
|
out_1 = silk_ADD32( S[ 0 ], X );
|
||
|
|
S[ 0 ] = silk_ADD32( in32, X );
|
||
|
|
|
||
|
|
/* Convert to Q10 */
|
||
|
|
in32 = silk_LSHIFT( (opus_int32)in[ 2 * k + 1 ], 10 );
|
||
|
|
|
||
|
|
/* All-pass section for odd input sample, and add to output of previous section */
|
||
|
|
Y = silk_SUB32( in32, S[ 1 ] );
|
||
|
|
X = silk_SMULWB( Y, A_fb1_20 );
|
||
|
|
out_2 = silk_ADD32( S[ 1 ], X );
|
||
|
|
S[ 1 ] = silk_ADD32( in32, X );
|
||
|
|
|
||
|
|
/* Add/subtract, convert back to int16 and store to output */
|
||
|
|
outL[ k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( silk_ADD32( out_2, out_1 ), 11 ) );
|
||
|
|
outH[ k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( silk_SUB32( out_2, out_1 ), 11 ) );
|
||
|
|
}
|
||
|
|
}
|