- initial import

src/libs/webrtc/ilbcfix/comp_corr.c

@@ -0,0 +1,49 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+/******************************************************************
+
+ iLBC Speech Coder ANSI-C Source Code
+
+ WebRtcIlbcfix_CompCorr.c
+
+******************************************************************/
+
+#include "defines.h"
+
+/*----------------------------------------------------------------*
+ *  Compute cross correlation and pitch gain for pitch prediction
+ *  of last subframe at given lag.
+ *---------------------------------------------------------------*/
+
+void WebRtcIlbcfix_CompCorr(
+    WebRtc_Word32 *corr, /* (o) cross correlation */
+    WebRtc_Word32 *ener, /* (o) energy */
+    WebRtc_Word16 *buffer, /* (i) signal buffer */
+    WebRtc_Word16 lag,  /* (i) pitch lag */
+    WebRtc_Word16 bLen, /* (i) length of buffer */
+    WebRtc_Word16 sRange, /* (i) correlation search length */
+    WebRtc_Word16 scale /* (i) number of rightshifts to use */
+                            ){
+  WebRtc_Word16 *w16ptr;
+
+  w16ptr=&buffer[bLen-sRange-lag];
+
+  /* Calculate correlation and energy */
+  (*corr)=WebRtcSpl_DotProductWithScale(&buffer[bLen-sRange], w16ptr, sRange, scale);
+  (*ener)=WebRtcSpl_DotProductWithScale(w16ptr, w16ptr, sRange, scale);
+
+  /* For zero energy set the energy to 0 in order to avoid potential
+     problems for coming divisions */
+  if (*ener == 0) {
+    *corr = 0;
+    *ener = 1;
+  }
+}