1 files changed, 108 insertions, 0 deletions
diff --git a/libAACenc/src/pre_echo_control.cpp b/libAACenc/src/pre_echo_control.cpp
new file mode 100644
index 0000000..dd34e22
--- /dev/null
+++ b/libAACenc/src/pre_echo_control.cpp
@@ -0,0 +1,108 @@
+/******************************** MPEG Audio Encoder **************************
+
+                       (C) copyright Fraunhofer IIS (1999)
+                               All Rights Reserved
+
+    Please be advised that this software and/or program delivery is
+    Confidential Information of Fraunhofer and subject to and covered by the
+
+    Fraunhofer IIS Software Evaluation Agreement
+    between Google Inc. and  Fraunhofer
+    effective and in full force since March 1, 2012.
+
+    You may use this software and/or program only under the terms and
+    conditions described in the above mentioned Fraunhofer IIS Software
+    Evaluation Agreement. Any other and/or further use requires a separate agreement.
+
+
+   $Id$
+   Initial author:       M.Werner
+   contents/description: Pre echo control
+
+   This software and/or program is protected by copyright law and international
+   treaties. Any reproduction or distribution of this software and/or program,
+   or any portion of it, may result in severe civil and criminal penalties, and
+   will be prosecuted to the maximum extent possible under law.
+
+******************************************************************************/
+
+#include "pre_echo_control.h"
+#include "psy_configuration.h"
+
+void FDKaacEnc_InitPreEchoControl(FIXP_DBL    *RESTRICT pbThresholdNm1,
+                                  INT         *calcPreEcho,
+                                  INT          numPb,
+                                  FIXP_DBL    *RESTRICT sfbPcmQuantThreshold,
+                                  INT         *mdctScalenm1)
+{
+  *mdctScalenm1 = PCM_QUANT_THR_SCALE>>1;
+
+  FDKmemcpy(pbThresholdNm1, sfbPcmQuantThreshold, numPb*sizeof(FIXP_DBL));
+
+  *calcPreEcho = 1;
+}
+
+
+void FDKaacEnc_PreEchoControl(FIXP_DBL   *RESTRICT pbThresholdNm1,
+                              INT         calcPreEcho,
+                              INT         numPb,
+                              INT         maxAllowedIncreaseFactor,
+                              FIXP_SGL    minRemainingThresholdFactor,
+                              FIXP_DBL   *RESTRICT pbThreshold,
+                              INT         mdctScale,
+                              INT        *mdctScalenm1)
+{
+    int i;
+    FIXP_DBL tmpThreshold1, tmpThreshold2;
+    int scaling;
+
+	/* If lastWindowSequence in previous frame was start- or stop-window,
+	   skip preechocontrol calculation */
+    if (calcPreEcho==0) {
+      /* copy thresholds to internal memory */
+      FDKmemcpy(pbThresholdNm1, pbThreshold, numPb*sizeof(FIXP_DBL));
+      *mdctScalenm1 = mdctScale;
+      return;
+    }
+
+    if ( mdctScale > *mdctScalenm1 ) {
+        /* if current thresholds are downscaled more than the ones from the last block */
+        scaling = 2*(mdctScale-*mdctScalenm1);
+        for(i = 0; i < numPb; i++) {
+
+            /* multiplication with return data type fract ist equivalent to int multiplication */
+            FDK_ASSERT(scaling>=0);
+            tmpThreshold1 = maxAllowedIncreaseFactor * (pbThresholdNm1[i]>>scaling);
+            tmpThreshold2 = fMult(minRemainingThresholdFactor, pbThreshold[i]);
+
+			FIXP_DBL tmp = pbThreshold[i];
+
+            /* copy thresholds to internal memory */
+            pbThresholdNm1[i] = tmp;
+
+            tmp = fixMin(tmp, tmpThreshold1);
+            pbThreshold[i] = fixMax(tmp, tmpThreshold2);
+        }
+    }
+    else {
+        /* if thresholds of last block are more downscaled than the current ones */
+        scaling = 2*(*mdctScalenm1-mdctScale);
+        for(i = 0; i < numPb; i++) {
+
+            /* multiplication with return data type fract ist equivalent to int multiplication */
+            tmpThreshold1 = (maxAllowedIncreaseFactor>>1) * pbThresholdNm1[i];
+            tmpThreshold2 = fMult(minRemainingThresholdFactor, pbThreshold[i]);
+
+            /* copy thresholds to internal memory */
+            pbThresholdNm1[i] = pbThreshold[i];
+
+            FDK_ASSERT(scaling>=0);
+            if((pbThreshold[i]>>(scaling+1)) > tmpThreshold1) {
+                pbThreshold[i] = tmpThreshold1<<(scaling+1);
+            }
+            pbThreshold[i] = fixMax(pbThreshold[i], tmpThreshold2);
+        }
+    }
+
+    *mdctScalenm1 = mdctScale;
+}