summaryrefslogtreecommitdiffstats
path: root/media/libopus/silk/float/apply_sine_window_FLP.c
diff options
context:
space:
mode:
Diffstat (limited to 'media/libopus/silk/float/apply_sine_window_FLP.c')
-rw-r--r--media/libopus/silk/float/apply_sine_window_FLP.c81
1 files changed, 81 insertions, 0 deletions
diff --git a/media/libopus/silk/float/apply_sine_window_FLP.c b/media/libopus/silk/float/apply_sine_window_FLP.c
new file mode 100644
index 000000000..6aae57c0a
--- /dev/null
+++ b/media/libopus/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, 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 Internet Society, IETF or IETF Trust, nor the
+names of specific contributors, may be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+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;
+ }
+}