The Tor Browser / file comparison
comparison: media/libopus/silk/fixed/apply_sine_window_FIX.c
media/libopus/silk/fixed/apply_sine_window_FIX.c
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
equal
deleted
inserted
replaced
| -1:000000000000 | 0:b0cec0466434 |
|---|---|
| 1 /*********************************************************************** | |
| 2 Copyright (c) 2006-2011, Skype Limited. All rights reserved. | |
| 3 Redistribution and use in source and binary forms, with or without | |
| 4 modification, are permitted provided that the following conditions | |
| 5 are met: | |
| 6 - Redistributions of source code must retain the above copyright notice, | |
| 7 this list of conditions and the following disclaimer. | |
| 8 - Redistributions in binary form must reproduce the above copyright | |
| 9 notice, this list of conditions and the following disclaimer in the | |
| 10 documentation and/or other materials provided with the distribution. | |
| 11 - Neither the name of Internet Society, IETF or IETF Trust, nor the | |
| 12 names of specific contributors, may be used to endorse or promote | |
| 13 products derived from this software without specific prior written | |
| 14 permission. | |
| 15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | |
| 19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 25 POSSIBILITY OF SUCH DAMAGE. | |
| 26 ***********************************************************************/ | |
| 27 | |
| 28 #ifdef HAVE_CONFIG_H | |
| 29 #include "config.h" | |
| 30 #endif | |
| 31 | |
| 32 #include "SigProc_FIX.h" | |
| 33 | |
| 34 /* Apply sine window to signal vector. */ | |
| 35 /* Window types: */ | |
| 36 /* 1 -> sine window from 0 to pi/2 */ | |
| 37 /* 2 -> sine window from pi/2 to pi */ | |
| 38 /* Every other sample is linearly interpolated, for speed. */ | |
| 39 /* Window length must be between 16 and 120 (incl) and a multiple of 4. */ | |
| 40 | |
| 41 /* Matlab code for table: | |
| 42 for k=16:9*4:16+2*9*4, fprintf(' %7.d,', -round(65536*pi ./ (k:4:k+8*4))); fprintf('\n'); end | |
| 43 */ | |
| 44 static const opus_int16 freq_table_Q16[ 27 ] = { | |
| 45 12111, 9804, 8235, 7100, 6239, 5565, 5022, 4575, 4202, | |
| 46 3885, 3612, 3375, 3167, 2984, 2820, 2674, 2542, 2422, | |
| 47 2313, 2214, 2123, 2038, 1961, 1889, 1822, 1760, 1702, | |
| 48 }; | |
| 49 | |
| 50 void silk_apply_sine_window( | |
| 51 opus_int16 px_win[], /* O Pointer to windowed signal */ | |
| 52 const opus_int16 px[], /* I Pointer to input signal */ | |
| 53 const opus_int win_type, /* I Selects a window type */ | |
| 54 const opus_int length /* I Window length, multiple of 4 */ | |
| 55 ) | |
| 56 { | |
| 57 opus_int k, f_Q16, c_Q16; | |
| 58 opus_int32 S0_Q16, S1_Q16; | |
| 59 | |
| 60 silk_assert( win_type == 1 || win_type == 2 ); | |
| 61 | |
| 62 /* Length must be in a range from 16 to 120 and a multiple of 4 */ | |
| 63 silk_assert( length >= 16 && length <= 120 ); | |
| 64 silk_assert( ( length & 3 ) == 0 ); | |
| 65 | |
| 66 /* Frequency */ | |
| 67 k = ( length >> 2 ) - 4; | |
| 68 silk_assert( k >= 0 && k <= 26 ); | |
| 69 f_Q16 = (opus_int)freq_table_Q16[ k ]; | |
| 70 | |
| 71 /* Factor used for cosine approximation */ | |
| 72 c_Q16 = silk_SMULWB( (opus_int32)f_Q16, -f_Q16 ); | |
| 73 silk_assert( c_Q16 >= -32768 ); | |
| 74 | |
| 75 /* initialize state */ | |
| 76 if( win_type == 1 ) { | |
| 77 /* start from 0 */ | |
| 78 S0_Q16 = 0; | |
| 79 /* approximation of sin(f) */ | |
| 80 S1_Q16 = f_Q16 + silk_RSHIFT( length, 3 ); | |
| 81 } else { | |
| 82 /* start from 1 */ | |
| 83 S0_Q16 = ( (opus_int32)1 << 16 ); | |
| 84 /* approximation of cos(f) */ | |
| 85 S1_Q16 = ( (opus_int32)1 << 16 ) + silk_RSHIFT( c_Q16, 1 ) + silk_RSHIFT( length, 4 ); | |
| 86 } | |
| 87 | |
| 88 /* Uses the recursive equation: sin(n*f) = 2 * cos(f) * sin((n-1)*f) - sin((n-2)*f) */ | |
| 89 /* 4 samples at a time */ | |
| 90 for( k = 0; k < length; k += 4 ) { | |
| 91 px_win[ k ] = (opus_int16)silk_SMULWB( silk_RSHIFT( S0_Q16 + S1_Q16, 1 ), px[ k ] ); | |
| 92 px_win[ k + 1 ] = (opus_int16)silk_SMULWB( S1_Q16, px[ k + 1] ); | |
| 93 S0_Q16 = silk_SMULWB( S1_Q16, c_Q16 ) + silk_LSHIFT( S1_Q16, 1 ) - S0_Q16 + 1; | |
| 94 S0_Q16 = silk_min( S0_Q16, ( (opus_int32)1 << 16 ) ); | |
| 95 | |
| 96 px_win[ k + 2 ] = (opus_int16)silk_SMULWB( silk_RSHIFT( S0_Q16 + S1_Q16, 1 ), px[ k + 2] ); | |
| 97 px_win[ k + 3 ] = (opus_int16)silk_SMULWB( S0_Q16, px[ k + 3 ] ); | |
| 98 S1_Q16 = silk_SMULWB( S0_Q16, c_Q16 ) + silk_LSHIFT( S0_Q16, 1 ) - S1_Q16; | |
| 99 S1_Q16 = silk_min( S1_Q16, ( (opus_int32)1 << 16 ) ); | |
| 100 } | |
| 101 } |
