media/libopus/silk/fixed/apply_sine_window_FIX.c@b8a032363ba2 (annotated)
media/libopus/silk/fixed/apply_sine_window_FIX.c
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | /*********************************************************************** |
| michael@0 | 2 | Copyright (c) 2006-2011, Skype Limited. All rights reserved. |
| michael@0 | 3 | Redistribution and use in source and binary forms, with or without |
| michael@0 | 4 | modification, are permitted provided that the following conditions |
| michael@0 | 5 | are met: |
| michael@0 | 6 | - Redistributions of source code must retain the above copyright notice, |
| michael@0 | 7 | this list of conditions and the following disclaimer. |
| michael@0 | 8 | - Redistributions in binary form must reproduce the above copyright |
| michael@0 | 9 | notice, this list of conditions and the following disclaimer in the |
| michael@0 | 10 | documentation and/or other materials provided with the distribution. |
| michael@0 | 11 | - Neither the name of Internet Society, IETF or IETF Trust, nor the |
| michael@0 | 12 | names of specific contributors, may be used to endorse or promote |
| michael@0 | 13 | products derived from this software without specific prior written |
| michael@0 | 14 | permission. |
| michael@0 | 15 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| michael@0 | 16 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| michael@0 | 17 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| michael@0 | 18 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| michael@0 | 19 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| michael@0 | 20 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| michael@0 | 21 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| michael@0 | 22 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| michael@0 | 23 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| michael@0 | 24 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| michael@0 | 25 | POSSIBILITY OF SUCH DAMAGE. |
| michael@0 | 26 | ***********************************************************************/ |
| michael@0 | 27 | |
| michael@0 | 28 | #ifdef HAVE_CONFIG_H |
| michael@0 | 29 | #include "config.h" |
| michael@0 | 30 | #endif |
| michael@0 | 31 | |
| michael@0 | 32 | #include "SigProc_FIX.h" |
| michael@0 | 33 | |
| michael@0 | 34 | /* Apply sine window to signal vector. */ |
| michael@0 | 35 | /* Window types: */ |
| michael@0 | 36 | /* 1 -> sine window from 0 to pi/2 */ |
| michael@0 | 37 | /* 2 -> sine window from pi/2 to pi */ |
| michael@0 | 38 | /* Every other sample is linearly interpolated, for speed. */ |
| michael@0 | 39 | /* Window length must be between 16 and 120 (incl) and a multiple of 4. */ |
| michael@0 | 40 | |
| michael@0 | 41 | /* Matlab code for table: |
| michael@0 | 42 | for k=16:9*4:16+2*9*4, fprintf(' %7.d,', -round(65536*pi ./ (k:4:k+8*4))); fprintf('\n'); end |
| michael@0 | 43 | */ |
| michael@0 | 44 | static const opus_int16 freq_table_Q16[ 27 ] = { |
| michael@0 | 45 | 12111, 9804, 8235, 7100, 6239, 5565, 5022, 4575, 4202, |
| michael@0 | 46 | 3885, 3612, 3375, 3167, 2984, 2820, 2674, 2542, 2422, |
| michael@0 | 47 | 2313, 2214, 2123, 2038, 1961, 1889, 1822, 1760, 1702, |
| michael@0 | 48 | }; |
| michael@0 | 49 | |
| michael@0 | 50 | void silk_apply_sine_window( |
| michael@0 | 51 | opus_int16 px_win[], /* O Pointer to windowed signal */ |
| michael@0 | 52 | const opus_int16 px[], /* I Pointer to input signal */ |
| michael@0 | 53 | const opus_int win_type, /* I Selects a window type */ |
| michael@0 | 54 | const opus_int length /* I Window length, multiple of 4 */ |
| michael@0 | 55 | ) |
| michael@0 | 56 | { |
| michael@0 | 57 | opus_int k, f_Q16, c_Q16; |
| michael@0 | 58 | opus_int32 S0_Q16, S1_Q16; |
| michael@0 | 59 | |
| michael@0 | 60 | silk_assert( win_type == 1 || win_type == 2 ); |
| michael@0 | 61 | |
| michael@0 | 62 | /* Length must be in a range from 16 to 120 and a multiple of 4 */ |
| michael@0 | 63 | silk_assert( length >= 16 && length <= 120 ); |
| michael@0 | 64 | silk_assert( ( length & 3 ) == 0 ); |
| michael@0 | 65 | |
| michael@0 | 66 | /* Frequency */ |
| michael@0 | 67 | k = ( length >> 2 ) - 4; |
| michael@0 | 68 | silk_assert( k >= 0 && k <= 26 ); |
| michael@0 | 69 | f_Q16 = (opus_int)freq_table_Q16[ k ]; |
| michael@0 | 70 | |
| michael@0 | 71 | /* Factor used for cosine approximation */ |
| michael@0 | 72 | c_Q16 = silk_SMULWB( (opus_int32)f_Q16, -f_Q16 ); |
| michael@0 | 73 | silk_assert( c_Q16 >= -32768 ); |
| michael@0 | 74 | |
| michael@0 | 75 | /* initialize state */ |
| michael@0 | 76 | if( win_type == 1 ) { |
| michael@0 | 77 | /* start from 0 */ |
| michael@0 | 78 | S0_Q16 = 0; |
| michael@0 | 79 | /* approximation of sin(f) */ |
| michael@0 | 80 | S1_Q16 = f_Q16 + silk_RSHIFT( length, 3 ); |
| michael@0 | 81 | } else { |
| michael@0 | 82 | /* start from 1 */ |
| michael@0 | 83 | S0_Q16 = ( (opus_int32)1 << 16 ); |
| michael@0 | 84 | /* approximation of cos(f) */ |
| michael@0 | 85 | S1_Q16 = ( (opus_int32)1 << 16 ) + silk_RSHIFT( c_Q16, 1 ) + silk_RSHIFT( length, 4 ); |
| michael@0 | 86 | } |
| michael@0 | 87 | |
| michael@0 | 88 | /* Uses the recursive equation: sin(n*f) = 2 * cos(f) * sin((n-1)*f) - sin((n-2)*f) */ |
| michael@0 | 89 | /* 4 samples at a time */ |
| michael@0 | 90 | for( k = 0; k < length; k += 4 ) { |
| michael@0 | 91 | px_win[ k ] = (opus_int16)silk_SMULWB( silk_RSHIFT( S0_Q16 + S1_Q16, 1 ), px[ k ] ); |
| michael@0 | 92 | px_win[ k + 1 ] = (opus_int16)silk_SMULWB( S1_Q16, px[ k + 1] ); |
| michael@0 | 93 | S0_Q16 = silk_SMULWB( S1_Q16, c_Q16 ) + silk_LSHIFT( S1_Q16, 1 ) - S0_Q16 + 1; |
| michael@0 | 94 | S0_Q16 = silk_min( S0_Q16, ( (opus_int32)1 << 16 ) ); |
| michael@0 | 95 | |
| michael@0 | 96 | px_win[ k + 2 ] = (opus_int16)silk_SMULWB( silk_RSHIFT( S0_Q16 + S1_Q16, 1 ), px[ k + 2] ); |
| michael@0 | 97 | px_win[ k + 3 ] = (opus_int16)silk_SMULWB( S0_Q16, px[ k + 3 ] ); |
| michael@0 | 98 | S1_Q16 = silk_SMULWB( S0_Q16, c_Q16 ) + silk_LSHIFT( S0_Q16, 1 ) - S1_Q16; |
| michael@0 | 99 | S1_Q16 = silk_min( S1_Q16, ( (opus_int32)1 << 16 ) ); |
| michael@0 | 100 | } |
| michael@0 | 101 | } |
