gecko-dev/media/libopus/silk/LPC_fit.c
Ralph Giles f4988a7a24 Bug 1372393 - opus: Update to 1.2-rc1. r=kinetik
Update our in-tree implementation of the opus audio codec
to the 1.2 release candidiate. This gives us some wider
testing before making the first stable release of the
new series.

This release improves the quality and compactness of encoded
audio, and optimizes performance on ARM NEON platforms.

MozReview-Commit-ID: 30bM6iVBamd

--HG--
extra : rebase_source : 7a679a4ea419dbfb242aeebf220518e2f9397977
2017-06-12 14:29:32 -07:00

82 lines
3.9 KiB
C

/***********************************************************************
Copyright (c) 2013, Koen Vos. 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"
/* Convert int32 coefficients to int16 coefs and make sure there's no wrap-around */
void silk_LPC_fit(
opus_int16 *a_QOUT, /* O Output signal */
opus_int32 *a_QIN, /* I/O Input signal */
const opus_int QOUT, /* I Input Q domain */
const opus_int QIN, /* I Input Q domain */
const opus_int d /* I Filter order */
)
{
opus_int i, k, idx = 0;
opus_int32 maxabs, absval, chirp_Q16;
/* Limit the maximum absolute value of the prediction coefficients, so that they'll fit in int16 */
for( i = 0; i < 10; i++ ) {
/* Find maximum absolute value and its index */
maxabs = 0;
for( k = 0; k < d; k++ ) {
absval = silk_abs( a_QIN[k] );
if( absval > maxabs ) {
maxabs = absval;
idx = k;
}
}
maxabs = silk_RSHIFT_ROUND( maxabs, QIN - QOUT );
if( maxabs > silk_int16_MAX ) {
/* Reduce magnitude of prediction coefficients */
maxabs = silk_min( maxabs, 163838 ); /* ( silk_int32_MAX >> 14 ) + silk_int16_MAX = 163838 */
chirp_Q16 = SILK_FIX_CONST( 0.999, 16 ) - silk_DIV32( silk_LSHIFT( maxabs - silk_int16_MAX, 14 ),
silk_RSHIFT32( silk_MUL( maxabs, idx + 1), 2 ) );
silk_bwexpander_32( a_QIN, d, chirp_Q16 );
} else {
break;
}
}
if( i == 10 ) {
/* Reached the last iteration, clip the coefficients */
for( k = 0; k < d; k++ ) {
a_QOUT[ k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( a_QIN[ k ], QIN - QOUT ) );
a_QIN[ k ] = silk_LSHIFT( (opus_int32)a_QOUT[ k ], QIN - QOUT );
}
} else {
for( k = 0; k < d; k++ ) {
a_QOUT[ k ] = (opus_int16)silk_RSHIFT_ROUND( a_QIN[ k ], QIN - QOUT );
}
}
}