diff options
author | Jean-Marc Valin <jmvalin@jmvalin.ca> | 2011-09-16 12:16:53 +0400 |
---|---|---|
committer | Jean-Marc Valin <jmvalin@jmvalin.ca> | 2011-09-16 12:16:53 +0400 |
commit | 1c2f5633d101c08b5ef8095a8682d3d52cbd952d (patch) | |
tree | 66f80e67f075db5fa5233759a89f475d8bedade2 /silk/float/apply_sine_window_FLP.c | |
parent | fb3a437c9dabb4aafe4a3927158161590ed745ab (diff) |
Removed all the silk_ prefixes in source file names (not symbols)
Diffstat (limited to 'silk/float/apply_sine_window_FLP.c')
-rw-r--r-- | silk/float/apply_sine_window_FLP.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/silk/float/apply_sine_window_FLP.c b/silk/float/apply_sine_window_FLP.c new file mode 100644 index 00000000..4de05dd7 --- /dev/null +++ b/silk/float/apply_sine_window_FLP.c @@ -0,0 +1,81 @@ +/*********************************************************************** +Copyright (c) 2006-2011, Skype Limited. All rights reserved. +Redistribution and use in source and binary forms, with or without +modification, (subject to the limitations in the disclaimer below) +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 Skype Limited, nor the names of specific +contributors, may be used to endorse or promote products derived from +this software without specific prior written permission. +NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED +BY THIS LICENSE. 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 "main_FLP.h" + +/* Apply sine window to signal vector. */ +/* Window types: */ +/* 1 -> sine window from 0 to pi/2 */ +/* 2 -> sine window from pi/2 to pi */ +void silk_apply_sine_window_FLP( + silk_float px_win[], /* O Pointer to windowed signal */ + const silk_float px[], /* I Pointer to input signal */ + const opus_int win_type, /* I Selects a window type */ + const opus_int length /* I Window length, multiple of 4 */ +) +{ + opus_int k; + silk_float freq, c, S0, S1; + + silk_assert( win_type == 1 || win_type == 2 ); + + /* Length must be multiple of 4 */ + silk_assert( ( length & 3 ) == 0 ); + + freq = PI / ( length + 1 ); + + /* Approximation of 2 * cos(f) */ + c = 2.0f - freq * freq; + + /* Initialize state */ + if( win_type < 2 ) { + /* Start from 0 */ + S0 = 0.0f; + /* Approximation of sin(f) */ + S1 = freq; + } else { + /* Start from 1 */ + S0 = 1.0f; + /* Approximation of cos(f) */ + S1 = 0.5f * c; + } + + /* Uses the recursive equation: sin(n*f) = 2 * cos(f) * sin((n-1)*f) - sin((n-2)*f) */ + /* 4 samples at a time */ + for( k = 0; k < length; k += 4 ) { + px_win[ k + 0 ] = px[ k + 0 ] * 0.5f * ( S0 + S1 ); + px_win[ k + 1 ] = px[ k + 1 ] * S1; + S0 = c * S1 - S0; + px_win[ k + 2 ] = px[ k + 2 ] * 0.5f * ( S1 + S0 ); + px_win[ k + 3 ] = px[ k + 3 ] * S0; + S1 = c * S0 - S1; + } +} |