First submission of audio effect library from NXP software.

This CL contains the first open sourceable version of the audio effect library from NXP software.
The effects implemented are:
- Bass boost
- Virtualizer (stereo widening)
- Equalizer
- Spectrum analyzer

Source file for the effect engines are located under libeffects/lvm/lib
The wrapper implementing the interface with the audio effect framework in under libeffects/lvm/wrapper

The code of other effect libraries has also been reorganized fo clarity:
- the effect factory is now under libeffects/factory
- the test equalizer and reverb effects are under libeffect/testlibs
- the visualizer is under libeffects/virtualizer

Change-Id: I8d91e2181f81b89f8fc0c1e1e6bf552c5809b2eb

1 files changed, 125 insertions, 0 deletions

diff --git a/media/libeffects/lvm/lib/Common/src/NonLinComp_D16.c b/media/libeffects/lvm/lib/Common/src/NonLinComp_D16.c
new file mode 100755
index 0000000..1428777
--- /dev/null
+++ b/media/libeffects/lvm/lib/Common/src/NonLinComp_D16.c
@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) 2004-2010 NXP Software
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**********************************************************************************
+
+     $Author: beq07716 $
+     $Revision: 1000 $
+     $Date: 2010-06-28 13:08:20 +0200 (Mon, 28 Jun 2010) $
+
+***********************************************************************************/
+
+/****************************************************************************************/
+/*                                                                                      */
+/*    Includes                                                                          */
+/*                                                                                      */
+/****************************************************************************************/
+
+#include "CompLim_private.h"
+
+/****************************************************************************************/
+/*                                                                                      */
+/* FUNCTION:                 NonLinComp_D16                                             */
+/*                                                                                      */
+/* DESCRIPTION:                                                                         */
+/*  Non-linear compression by companding. The function works on a sample by sample      */
+/*  basis by increasing the level near the zero crossing. This gives a ttrade-off       */
+/*  between THD and compression. It uses the equation:                                  */
+/*                                                                                      */
+/*        Output = Input + K * (Input - Input^2)        if Input >  0                   */
+/*               = Input + K * (Input + Input^2)      if Input <= 0                     */
+/*                                                                                      */
+/*    The value of K controls the amount of compression and as a side effect the amount */
+/*  distortion introduced. The amount of compression is signal dependent and the values */
+/*  given below are approximate.                                                        */
+/*                                                                                      */
+/*        Gain (fractional)  Gain (integer)    Compression          Pk-Pk THD           */
+/*            1.0                 32767            +6dB            16dB                 */
+/*            0.78                25559            +5dB            19dB                 */
+/*            0.6                 19661            +4dB            21dB                 */
+/*            0.41                13435            +3dB            24dB                 */
+/*            0.26                 8520            +2dB            28dB                 */
+/*            0.12                 3932            +1dB            34dB                 */
+/*            0.0                     0            +0dB            98dB                 */
+/*                                                                                      */
+/* PARAMETERS:                                                                          */
+/*    Gain            -    compression control parameter                                */
+/*    pDataIn         -    pointer to the input data buffer                             */
+/*    pDataOut        -    pointer to the output data buffer                            */
+/*    BlockLength     -    number of samples to process                                 */
+/*                                                                                      */
+/* RETURNS:                                                                             */
+/*    None                                                                              */
+/*                                                                                      */
+/* NOTES:                                                                               */
+/*                                                                                      */
+/****************************************************************************************/
+
+void NonLinComp_D16(LVM_INT16        Gain,
+                      LVM_INT16        *pDataIn,
+                    LVM_INT16        *pDataOut,
+                    LVM_INT32        BlockLength)
+{
+
+    LVM_INT16            Sample;                    /* Input samples */
+    LVM_INT32            SampleNo;                /* Sample index */
+    LVM_INT16            Temp;
+
+
+    /*
+     * Process a block of samples
+     */
+    for(SampleNo = 0; SampleNo<BlockLength; SampleNo++)
+    {
+
+        /*
+         * Read the input
+         */
+        Sample = *pDataIn;
+        pDataIn++;
+
+
+        /*
+         * Apply the compander, this compresses the signal at the expense of
+         * harmonic distortion. The amount of compression is control by the
+         * gain factor
+         */
+        if ((LVM_INT32)Sample != -32768)
+        {
+            Temp = (LVM_INT16)((Sample * Sample) >> 15);
+            if(Sample >0)
+            {
+                Sample = (LVM_INT16)(Sample + ((Gain * (Sample - Temp)) >> 15));
+            }
+            else
+            {
+                Sample = (LVM_INT16)(Sample + ((Gain * (Sample + Temp)) >> 15));
+            }
+        }
+
+
+        /*
+         * Save the output
+         */
+        *pDataOut = Sample;
+        pDataOut++;
+
+
+    }
+
+}
+