1885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org/*********************************************************************** 2885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgCopyright (c) 2006-2011, Skype Limited. All rights reserved. 3885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgRedistribution and use in source and binary forms, with or without 4885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgmodification, are permitted provided that the following conditions 5885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgare met: 6885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org- Redistributions of source code must retain the above copyright notice, 7885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgthis list of conditions and the following disclaimer. 8885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org- Redistributions in binary form must reproduce the above copyright 9885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgnotice, this list of conditions and the following disclaimer in the 10885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgdocumentation and/or other materials provided with the distribution. 11e3ea049fcaee2247e45f0ce793d4313babb4ef69tlegrand@chromium.org- Neither the name of Internet Society, IETF or IETF Trust, nor the 12885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgnames of specific contributors, may be used to endorse or promote 13885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgproducts derived from this software without specific prior written 14885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgpermission. 15e3ea049fcaee2247e45f0ce793d4313babb4ef69tlegrand@chromium.orgTHIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 16885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgAND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgIMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 19885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgLIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgCONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgSUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgINTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgCONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgPOSSIBILITY OF SUCH DAMAGE. 26885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org***********************************************************************/ 27885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 28885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#ifdef HAVE_CONFIG_H 29885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#include "config.h" 30885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#endif 31885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 32885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#include "SigProc_FIX.h" 33885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#include "resampler_rom.h" 34885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 35885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org/* Downsample by a factor 2 */ 36885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgvoid silk_resampler_down2( 37885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org opus_int32 *S, /* I/O State vector [ 2 ] */ 38e3ea049fcaee2247e45f0ce793d4313babb4ef69tlegrand@chromium.org opus_int16 *out, /* O Output signal [ floor(len/2) ] */ 39e3ea049fcaee2247e45f0ce793d4313babb4ef69tlegrand@chromium.org const opus_int16 *in, /* I Input signal [ len ] */ 40885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org opus_int32 inLen /* I Number of input samples */ 41885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org) 42885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org{ 43885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org opus_int32 k, len2 = silk_RSHIFT32( inLen, 1 ); 44885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org opus_int32 in32, out32, Y, X; 45885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 46885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org silk_assert( silk_resampler_down2_0 > 0 ); 47885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org silk_assert( silk_resampler_down2_1 < 0 ); 48885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 49885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org /* Internal variables and state are in Q10 format */ 50885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org for( k = 0; k < len2; k++ ) { 51885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org /* Convert to Q10 */ 52885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org in32 = silk_LSHIFT( (opus_int32)in[ 2 * k ], 10 ); 53885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 54885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org /* All-pass section for even input sample */ 55885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org Y = silk_SUB32( in32, S[ 0 ] ); 56885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org X = silk_SMLAWB( Y, Y, silk_resampler_down2_1 ); 57885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org out32 = silk_ADD32( S[ 0 ], X ); 58885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org S[ 0 ] = silk_ADD32( in32, X ); 59885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 60885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org /* Convert to Q10 */ 61885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org in32 = silk_LSHIFT( (opus_int32)in[ 2 * k + 1 ], 10 ); 62885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 63885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org /* All-pass section for odd input sample, and add to output of previous section */ 64885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org Y = silk_SUB32( in32, S[ 1 ] ); 65885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org X = silk_SMULWB( Y, silk_resampler_down2_0 ); 66885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org out32 = silk_ADD32( out32, S[ 1 ] ); 67885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org out32 = silk_ADD32( out32, X ); 68885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org S[ 1 ] = silk_ADD32( in32, X ); 69885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 70885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org /* Add, convert back to int16 and store to output */ 71885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org out[ k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( out32, 11 ) ); 72885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org } 73885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org} 74885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 75