1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libopus/silk/resampler_down2_3.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,103 @@
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 +#include "resampler_private.h"
1.37 +#include "stack_alloc.h"
1.38 +
1.39 +#define ORDER_FIR 4
1.40 +
1.41 +/* Downsample by a factor 2/3, low quality */
1.42 +void silk_resampler_down2_3(
1.43 + opus_int32 *S, /* I/O State vector [ 6 ] */
1.44 + opus_int16 *out, /* O Output signal [ floor(2*inLen/3) ] */
1.45 + const opus_int16 *in, /* I Input signal [ inLen ] */
1.46 + opus_int32 inLen /* I Number of input samples */
1.47 +)
1.48 +{
1.49 + opus_int32 nSamplesIn, counter, res_Q6;
1.50 + VARDECL( opus_int32, buf );
1.51 + opus_int32 *buf_ptr;
1.52 + SAVE_STACK;
1.53 +
1.54 + ALLOC( buf, RESAMPLER_MAX_BATCH_SIZE_IN + ORDER_FIR, opus_int32 );
1.55 +
1.56 + /* Copy buffered samples to start of buffer */
1.57 + silk_memcpy( buf, S, ORDER_FIR * sizeof( opus_int32 ) );
1.58 +
1.59 + /* Iterate over blocks of frameSizeIn input samples */
1.60 + while( 1 ) {
1.61 + nSamplesIn = silk_min( inLen, RESAMPLER_MAX_BATCH_SIZE_IN );
1.62 +
1.63 + /* Second-order AR filter (output in Q8) */
1.64 + silk_resampler_private_AR2( &S[ ORDER_FIR ], &buf[ ORDER_FIR ], in,
1.65 + silk_Resampler_2_3_COEFS_LQ, nSamplesIn );
1.66 +
1.67 + /* Interpolate filtered signal */
1.68 + buf_ptr = buf;
1.69 + counter = nSamplesIn;
1.70 + while( counter > 2 ) {
1.71 + /* Inner product */
1.72 + res_Q6 = silk_SMULWB( buf_ptr[ 0 ], silk_Resampler_2_3_COEFS_LQ[ 2 ] );
1.73 + res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 1 ], silk_Resampler_2_3_COEFS_LQ[ 3 ] );
1.74 + res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 2 ], silk_Resampler_2_3_COEFS_LQ[ 5 ] );
1.75 + res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 3 ], silk_Resampler_2_3_COEFS_LQ[ 4 ] );
1.76 +
1.77 + /* Scale down, saturate and store in output array */
1.78 + *out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q6, 6 ) );
1.79 +
1.80 + res_Q6 = silk_SMULWB( buf_ptr[ 1 ], silk_Resampler_2_3_COEFS_LQ[ 4 ] );
1.81 + res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 2 ], silk_Resampler_2_3_COEFS_LQ[ 5 ] );
1.82 + res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 3 ], silk_Resampler_2_3_COEFS_LQ[ 3 ] );
1.83 + res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 4 ], silk_Resampler_2_3_COEFS_LQ[ 2 ] );
1.84 +
1.85 + /* Scale down, saturate and store in output array */
1.86 + *out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q6, 6 ) );
1.87 +
1.88 + buf_ptr += 3;
1.89 + counter -= 3;
1.90 + }
1.91 +
1.92 + in += nSamplesIn;
1.93 + inLen -= nSamplesIn;
1.94 +
1.95 + if( inLen > 0 ) {
1.96 + /* More iterations to do; copy last part of filtered signal to beginning of buffer */
1.97 + silk_memcpy( buf, &buf[ nSamplesIn ], ORDER_FIR * sizeof( opus_int32 ) );
1.98 + } else {
1.99 + break;
1.100 + }
1.101 + }
1.102 +
1.103 + /* Copy last part of filtered signal to the state for the next call */
1.104 + silk_memcpy( S, &buf[ nSamplesIn ], ORDER_FIR * sizeof( opus_int32 ) );
1.105 + RESTORE_STACK;
1.106 +}
