diff options
Diffstat (limited to 'silk/SKP_Silk_LPC_inv_pred_gain_FLP.c')
| m--------- | silk | 6 | ||||
| -rw-r--r-- | silk/SKP_Silk_LPC_inv_pred_gain_FLP.c | 81 |
2 files changed, 81 insertions, 6 deletions
diff --git a/silk b/silk deleted file mode 160000 -Subproject 8a8b76efeeccaccf402b0b2b4e469980d0a4831 diff --git a/silk/SKP_Silk_LPC_inv_pred_gain_FLP.c b/silk/SKP_Silk_LPC_inv_pred_gain_FLP.c new file mode 100644 index 00000000..4b2f2f2b --- /dev/null +++ b/silk/SKP_Silk_LPC_inv_pred_gain_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.
+***********************************************************************/
+
+/* *
+ * SKP_Silk_LPC_inverse_pred_gain.c *
+ * *
+ * compute inverse of LPC prediction gain, and *
+ * test if LPC coefficients are stable (all poles within unit circle) *
+ * *
+ * Copyright 2008 (c), Skype Limited *
+ * */
+#include "SKP_Silk_SigProc_FIX.h"
+#include "SKP_Silk_SigProc_FLP.h"
+
+#define RC_THRESHOLD 0.9999f
+
+/* compute inverse of LPC prediction gain, and */
+/* test if LPC coefficients are stable (all poles within unit circle) */
+/* this code is based on SKP_Silk_a2k_FLP() */
+SKP_int SKP_Silk_LPC_inverse_pred_gain_FLP( /* O: returns 1 if unstable, otherwise 0 */
+ SKP_float *invGain, /* O: inverse prediction gain, energy domain */
+ const SKP_float *A, /* I: prediction coefficients [order] */
+ SKP_int32 order /* I: prediction order */
+)
+{
+ SKP_int k, n;
+ double rc, rc_mult1, rc_mult2;
+ SKP_float Atmp[ 2 ][ SKP_Silk_MAX_ORDER_LPC ];
+ SKP_float *Aold, *Anew;
+
+ Anew = Atmp[ order & 1 ];
+ SKP_memcpy( Anew, A, order * sizeof(SKP_float) );
+
+ *invGain = 1.0f;
+ for( k = order - 1; k > 0; k-- ) {
+ rc = -Anew[ k ];
+ if (rc > RC_THRESHOLD || rc < -RC_THRESHOLD) {
+ return 1;
+ }
+ rc_mult1 = 1.0f - rc * rc;
+ rc_mult2 = 1.0f / rc_mult1;
+ *invGain *= (SKP_float)rc_mult1;
+ /* swap pointers */
+ Aold = Anew;
+ Anew = Atmp[ k & 1 ];
+ for( n = 0; n < k; n++ ) {
+ Anew[ n ] = (SKP_float)( ( Aold[ n ] - Aold[ k - n - 1 ] * rc ) * rc_mult2 );
+ }
+ }
+ rc = -Anew[ 0 ];
+ if ( rc > RC_THRESHOLD || rc < -RC_THRESHOLD ) {
+ return 1;
+ }
+ rc_mult1 = 1.0f - rc * rc;
+ *invGain *= (SKP_float)rc_mult1;
+ return 0;
+}
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