LoudnessEnhancer audio effect implementation

Implementation based on DRC effect, controlled by a
 target gain.
 The target gain is used to amplify the signal at
 the input of the DRC, and to compute the knee
 of the DRC.

Bug 8413913

Change-Id: I386d64793a9fa3f7218e053d6f0a99f6836c02bd

18 files changed, 1865 insertions, 0 deletions

diff --git a/media/libeffects/loudness/Android.mk b/media/libeffects/loudness/Android.mk
new file mode 100644
index 0000000..dcb7b27
--- /dev/null
+++ b/media/libeffects/loudness/Android.mk
@@ -0,0 +1,27 @@
+LOCAL_PATH:= $(call my-dir)
+
+# LoudnessEnhancer library
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES:= \
+	EffectLoudnessEnhancer.cpp \
+	dsp/core/dynamic_range_compression.cpp
+
+LOCAL_CFLAGS+= -O2 -fvisibility=hidden
+
+LOCAL_SHARED_LIBRARIES := \
+	libcutils \
+	liblog \
+	libstlport
+
+LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/soundfx
+LOCAL_MODULE:= libldnhncr
+
+LOCAL_C_INCLUDES := \
+	$(call include-path-for, audio-effects) \
+	bionic \
+	bionic/libstdc++/include \
+	external/stlport/stlport
+
+
+include $(BUILD_SHARED_LIBRARY)
diff --git a/media/libeffects/loudness/EffectLoudnessEnhancer.cpp b/media/libeffects/loudness/EffectLoudnessEnhancer.cpp
new file mode 100644
index 0000000..dfc25db
--- /dev/null
+++ b/media/libeffects/loudness/EffectLoudnessEnhancer.cpp
@@ -0,0 +1,474 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#define LOG_TAG "EffectLE"
+//#define LOG_NDEBUG 0
+#include <cutils/log.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <new>
+#include <time.h>
+#include <math.h>
+#include <audio_effects/effect_loudnessenhancer.h>
+#include "dsp/core/dynamic_range_compression.h"
+
+extern "C" {
+
+// effect_handle_t interface implementation for LE effect
+extern const struct effect_interface_s gLEInterface;
+
+// AOSP Loudness Enhancer UUID: fa415329-2034-4bea-b5dc-5b381c8d1e2c
+const effect_descriptor_t gLEDescriptor = {
+        {0xfe3199be, 0xaed0, 0x413f, 0x87bb, {0x11, 0x26, 0x0e, 0xb6, 0x3c, 0xf1}}, // type
+        {0xfa415329, 0x2034, 0x4bea, 0xb5dc, {0x5b, 0x38, 0x1c, 0x8d, 0x1e, 0x2c}}, // uuid
+        EFFECT_CONTROL_API_VERSION,
+        (EFFECT_FLAG_TYPE_INSERT | EFFECT_FLAG_INSERT_FIRST),
+        0, // TODO
+        1,
+        "Loudness Enhancer",
+        "The Android Open Source Project",
+};
+
+enum le_state_e {
+    LOUDNESS_ENHANCER_STATE_UNINITIALIZED,
+    LOUDNESS_ENHANCER_STATE_INITIALIZED,
+    LOUDNESS_ENHANCER_STATE_ACTIVE,
+};
+
+struct LoudnessEnhancerContext {
+    const struct effect_interface_s *mItfe;
+    effect_config_t mConfig;
+    uint8_t mState;
+    int32_t mTargetGainmB;// target gain in mB
+    // in this implementation, there is no coupling between the compression on the left and right
+    // channels
+    le_fx::AdaptiveDynamicRangeCompression* mCompressorL;
+    le_fx::AdaptiveDynamicRangeCompression* mCompressorR;
+};
+
+//
+//--- Local functions (not directly used by effect interface)
+//
+
+void LE_reset(LoudnessEnhancerContext *pContext)
+{
+    ALOGV("  > LE_reset(%p)", pContext);
+
+    if ((pContext->mCompressorL != NULL) && (pContext->mCompressorR != NULL)) {
+        float targetAmp = pow(10, pContext->mTargetGainmB/2000.0f); // mB to linear amplification
+        ALOGV("LE_reset(): Target gain=%dmB <=> factor=%.2fX", pContext->mTargetGainmB, targetAmp);
+        pContext->mCompressorL->Initialize(targetAmp, pContext->mConfig.inputCfg.samplingRate);
+        pContext->mCompressorR->Initialize(targetAmp, pContext->mConfig.inputCfg.samplingRate);
+    } else {
+        ALOGE("LE_reset(%p): null compressors, can't apply target gain", pContext);
+    }
+}
+
+static inline int16_t clamp16(int32_t sample)
+{
+    if ((sample>>15) ^ (sample>>31))
+        sample = 0x7FFF ^ (sample>>31);
+    return sample;
+}
+
+//----------------------------------------------------------------------------
+// LE_setConfig()
+//----------------------------------------------------------------------------
+// Purpose: Set input and output audio configuration.
+//
+// Inputs:
+//  pContext:   effect engine context
+//  pConfig:    pointer to effect_config_t structure holding input and output
+//      configuration parameters
+//
+// Outputs:
+//
+//----------------------------------------------------------------------------
+
+int LE_setConfig(LoudnessEnhancerContext *pContext, effect_config_t *pConfig)
+{
+    ALOGV("LE_setConfig(%p)", pContext);
+
+    if (pConfig->inputCfg.samplingRate != pConfig->outputCfg.samplingRate) return -EINVAL;
+    if (pConfig->inputCfg.channels != pConfig->outputCfg.channels) return -EINVAL;
+    if (pConfig->inputCfg.format != pConfig->outputCfg.format) return -EINVAL;
+    if (pConfig->inputCfg.channels != AUDIO_CHANNEL_OUT_STEREO) return -EINVAL;
+    if (pConfig->outputCfg.accessMode != EFFECT_BUFFER_ACCESS_WRITE &&
+            pConfig->outputCfg.accessMode != EFFECT_BUFFER_ACCESS_ACCUMULATE) return -EINVAL;
+    if (pConfig->inputCfg.format != AUDIO_FORMAT_PCM_16_BIT) return -EINVAL;
+
+    pContext->mConfig = *pConfig;
+
+    LE_reset(pContext);
+
+    return 0;
+}
+
+
+//----------------------------------------------------------------------------
+// LE_getConfig()
+//----------------------------------------------------------------------------
+// Purpose: Get input and output audio configuration.
+//
+// Inputs:
+//  pContext:   effect engine context
+//  pConfig:    pointer to effect_config_t structure holding input and output
+//      configuration parameters
+//
+// Outputs:
+//
+//----------------------------------------------------------------------------
+
+void LE_getConfig(LoudnessEnhancerContext *pContext, effect_config_t *pConfig)
+{
+    *pConfig = pContext->mConfig;
+}
+
+
+//----------------------------------------------------------------------------
+// LE_init()
+//----------------------------------------------------------------------------
+// Purpose: Initialize engine with default configuration.
+//
+// Inputs:
+//  pContext:   effect engine context
+//
+// Outputs:
+//
+//----------------------------------------------------------------------------
+
+int LE_init(LoudnessEnhancerContext *pContext)
+{
+    ALOGV("LE_init(%p)", pContext);
+
+    pContext->mConfig.inputCfg.accessMode = EFFECT_BUFFER_ACCESS_READ;
+    pContext->mConfig.inputCfg.channels = AUDIO_CHANNEL_OUT_STEREO;
+    pContext->mConfig.inputCfg.format = AUDIO_FORMAT_PCM_16_BIT;
+    pContext->mConfig.inputCfg.samplingRate = 44100;
+    pContext->mConfig.inputCfg.bufferProvider.getBuffer = NULL;
+    pContext->mConfig.inputCfg.bufferProvider.releaseBuffer = NULL;
+    pContext->mConfig.inputCfg.bufferProvider.cookie = NULL;
+    pContext->mConfig.inputCfg.mask = EFFECT_CONFIG_ALL;
+    pContext->mConfig.outputCfg.accessMode = EFFECT_BUFFER_ACCESS_ACCUMULATE;
+    pContext->mConfig.outputCfg.channels = AUDIO_CHANNEL_OUT_STEREO;
+    pContext->mConfig.outputCfg.format = AUDIO_FORMAT_PCM_16_BIT;
+    pContext->mConfig.outputCfg.samplingRate = 44100;
+    pContext->mConfig.outputCfg.bufferProvider.getBuffer = NULL;
+    pContext->mConfig.outputCfg.bufferProvider.releaseBuffer = NULL;
+    pContext->mConfig.outputCfg.bufferProvider.cookie = NULL;
+    pContext->mConfig.outputCfg.mask = EFFECT_CONFIG_ALL;
+
+    pContext->mTargetGainmB = LOUDNESS_ENHANCER_DEFAULT_TARGET_GAIN_MB;
+    float targetAmp = pow(10, pContext->mTargetGainmB/2000.0f); // mB to linear amplification
+    ALOGV("LE_init(): Target gain=%dmB <=> factor=%.2fX", pContext->mTargetGainmB, targetAmp);
+
+    if (pContext->mCompressorL == NULL) {
+        pContext->mCompressorL = new le_fx::AdaptiveDynamicRangeCompression();
+        pContext->mCompressorL->Initialize(targetAmp, pContext->mConfig.inputCfg.samplingRate);
+    }
+    if (pContext->mCompressorR == NULL) {
+        pContext->mCompressorR = new le_fx::AdaptiveDynamicRangeCompression();
+        pContext->mCompressorR->Initialize(targetAmp, pContext->mConfig.inputCfg.samplingRate);
+    }
+
+    LE_setConfig(pContext, &pContext->mConfig);
+
+    return 0;
+}
+
+//
+//--- Effect Library Interface Implementation
+//
+
+int LELib_Create(const effect_uuid_t *uuid,
+                         int32_t sessionId,
+                         int32_t ioId,
+                         effect_handle_t *pHandle) {
+    ALOGV("LELib_Create()");
+    int ret;
+    int i;
+
+    if (pHandle == NULL || uuid == NULL) {
+        return -EINVAL;
+    }
+
+    if (memcmp(uuid, &gLEDescriptor.uuid, sizeof(effect_uuid_t)) != 0) {
+        return -EINVAL;
+    }
+
+    LoudnessEnhancerContext *pContext = new LoudnessEnhancerContext;
+
+    pContext->mItfe = &gLEInterface;
+    pContext->mState = LOUDNESS_ENHANCER_STATE_UNINITIALIZED;
+
+    pContext->mCompressorL = NULL;
+    pContext->mCompressorR = NULL;
+    ret = LE_init(pContext);
+    if (ret < 0) {
+        ALOGW("LELib_Create() init failed");
+        delete pContext;
+        return ret;
+    }
+
+    *pHandle = (effect_handle_t)pContext;
+
+    pContext->mState = LOUDNESS_ENHANCER_STATE_INITIALIZED;
+
+    ALOGV("  LELib_Create context is %p", pContext);
+
+    return 0;
+
+}
+
+int LELib_Release(effect_handle_t handle) {
+    LoudnessEnhancerContext * pContext = (LoudnessEnhancerContext *)handle;
+
+    ALOGV("LELib_Release %p", handle);
+    if (pContext == NULL) {
+        return -EINVAL;
+    }
+    pContext->mState = LOUDNESS_ENHANCER_STATE_UNINITIALIZED;
+    if (pContext->mCompressorL != NULL) {
+        delete pContext->mCompressorL;
+        pContext->mCompressorL = NULL;
+    }
+    if (pContext->mCompressorR != NULL) {
+        delete pContext->mCompressorR;
+        pContext->mCompressorR = NULL;
+    }
+    delete pContext;
+
+    return 0;
+}
+
+int LELib_GetDescriptor(const effect_uuid_t *uuid,
+                                effect_descriptor_t *pDescriptor) {
+
+    if (pDescriptor == NULL || uuid == NULL){
+        ALOGV("LELib_GetDescriptor() called with NULL pointer");
+        return -EINVAL;
+    }
+
+    if (memcmp(uuid, &gLEDescriptor.uuid, sizeof(effect_uuid_t)) == 0) {
+        *pDescriptor = gLEDescriptor;
+        return 0;
+    }
+
+    return  -EINVAL;
+} /* end LELib_GetDescriptor */
+
+//
+//--- Effect Control Interface Implementation
+//
+int LE_process(
+        effect_handle_t self, audio_buffer_t *inBuffer, audio_buffer_t *outBuffer)
+{
+    LoudnessEnhancerContext * pContext = (LoudnessEnhancerContext *)self;
+
+    if (pContext == NULL) {
+        return -EINVAL;
+    }
+
+    if (inBuffer == NULL || inBuffer->raw == NULL ||
+        outBuffer == NULL || outBuffer->raw == NULL ||
+        inBuffer->frameCount != outBuffer->frameCount ||
+        inBuffer->frameCount == 0) {
+        return -EINVAL;
+    }
+
+    //ALOGV("LE about to process %d samples", inBuffer->frameCount);
+    uint16_t inIdx;
+    float inputAmp = pow(10, pContext->mTargetGainmB/2000.0f);
+    for (inIdx = 0 ; inIdx < inBuffer->frameCount ; inIdx++) {
+        inBuffer->s16[2*inIdx] = pContext->mCompressorL->Compress(
+                inputAmp * (float)inBuffer->s16[2*inIdx]);
+        inBuffer->s16[2*inIdx +1] = pContext->mCompressorR->Compress(
+                inputAmp * (float)inBuffer->s16[2*inIdx +1]);
+    }
+
+    if (inBuffer->raw != outBuffer->raw) {
+        if (pContext->mConfig.outputCfg.accessMode == EFFECT_BUFFER_ACCESS_ACCUMULATE) {
+            for (size_t i = 0; i < outBuffer->frameCount*2; i++) {
+                outBuffer->s16[i] = clamp16(outBuffer->s16[i] + inBuffer->s16[i]);
+            }
+        } else {
+            memcpy(outBuffer->raw, inBuffer->raw, outBuffer->frameCount * 2 * sizeof(int16_t));
+        }
+    }
+    if (pContext->mState != LOUDNESS_ENHANCER_STATE_ACTIVE) {
+        return -ENODATA;
+    }
+    return 0;
+}
+
+int LE_command(effect_handle_t self, uint32_t cmdCode, uint32_t cmdSize,
+        void *pCmdData, uint32_t *replySize, void *pReplyData) {
+
+    LoudnessEnhancerContext * pContext = (LoudnessEnhancerContext *)self;
+    int retsize;
+
+    if (pContext == NULL || pContext->mState == LOUDNESS_ENHANCER_STATE_UNINITIALIZED) {
+        return -EINVAL;
+    }
+
+//    ALOGV("LE_command command %d cmdSize %d",cmdCode, cmdSize);
+    switch (cmdCode) {
+    case EFFECT_CMD_INIT:
+        if (pReplyData == NULL || *replySize != sizeof(int)) {
+            return -EINVAL;
+        }
+        *(int *) pReplyData = LE_init(pContext);
+        break;
+    case EFFECT_CMD_SET_CONFIG:
+        if (pCmdData == NULL || cmdSize != sizeof(effect_config_t)
+                || pReplyData == NULL || *replySize != sizeof(int)) {
+            return -EINVAL;
+        }
+        *(int *) pReplyData = LE_setConfig(pContext,
+                (effect_config_t *) pCmdData);
+        break;
+    case EFFECT_CMD_GET_CONFIG:
+        if (pReplyData == NULL ||
+            *replySize != sizeof(effect_config_t)) {
+            return -EINVAL;
+        }
+        LE_getConfig(pContext, (effect_config_t *)pReplyData);
+        break;
+    case EFFECT_CMD_RESET:
+        LE_reset(pContext);
+        break;
+    case EFFECT_CMD_ENABLE:
+        if (pReplyData == NULL || *replySize != sizeof(int)) {
+            return -EINVAL;
+        }
+        if (pContext->mState != LOUDNESS_ENHANCER_STATE_INITIALIZED) {
+            return -ENOSYS;
+        }
+        pContext->mState = LOUDNESS_ENHANCER_STATE_ACTIVE;
+        ALOGV("EFFECT_CMD_ENABLE() OK");
+        *(int *)pReplyData = 0;
+        break;
+    case EFFECT_CMD_DISABLE:
+        if (pReplyData == NULL || *replySize != sizeof(int)) {
+            return -EINVAL;
+        }
+        if (pContext->mState != LOUDNESS_ENHANCER_STATE_ACTIVE) {
+            return -ENOSYS;
+        }
+        pContext->mState = LOUDNESS_ENHANCER_STATE_INITIALIZED;
+        ALOGV("EFFECT_CMD_DISABLE() OK");
+        *(int *)pReplyData = 0;
+        break;
+    case EFFECT_CMD_GET_PARAM: {
+        if (pCmdData == NULL ||
+            cmdSize != (int)(sizeof(effect_param_t) + sizeof(uint32_t)) ||
+            pReplyData == NULL ||
+            *replySize < (int)(sizeof(effect_param_t) + sizeof(uint32_t) + sizeof(uint32_t))) {
+            return -EINVAL;
+        }
+        memcpy(pReplyData, pCmdData, sizeof(effect_param_t) + sizeof(uint32_t));
+        effect_param_t *p = (effect_param_t *)pReplyData;
+        p->status = 0;
+        *replySize = sizeof(effect_param_t) + sizeof(uint32_t);
+        if (p->psize != sizeof(uint32_t)) {
+            p->status = -EINVAL;
+            break;
+        }
+        switch (*(uint32_t *)p->data) {
+        case LOUDNESS_ENHANCER_PARAM_TARGET_GAIN_MB:
+            ALOGV("get target gain(mB) = %d", pContext->mTargetGainmB);
+            *((int32_t *)p->data + 1) = pContext->mTargetGainmB;
+            p->vsize = sizeof(int32_t);
+            *replySize += sizeof(int32_t);
+            break;
+        default:
+            p->status = -EINVAL;
+        }
+        } break;
+    case EFFECT_CMD_SET_PARAM: {
+        if (pCmdData == NULL ||
+            cmdSize != (int)(sizeof(effect_param_t) + sizeof(uint32_t) + sizeof(uint32_t)) ||
+            pReplyData == NULL || *replySize != sizeof(int32_t)) {
+            return -EINVAL;
+        }
+        *(int32_t *)pReplyData = 0;
+        effect_param_t *p = (effect_param_t *)pCmdData;
+        if (p->psize != sizeof(uint32_t) || p->vsize != sizeof(uint32_t)) {
+            *(int32_t *)pReplyData = -EINVAL;
+            break;
+        }
+        switch (*(uint32_t *)p->data) {
+        case LOUDNESS_ENHANCER_PARAM_TARGET_GAIN_MB:
+            pContext->mTargetGainmB = *((int32_t *)p->data + 1);
+            ALOGV("set target gain(mB) = %d", pContext->mTargetGainmB);
+            LE_reset(pContext); // apply parameter update
+            break;
+        default:
+            *(int32_t *)pReplyData = -EINVAL;
+        }
+        } break;
+    case EFFECT_CMD_SET_DEVICE:
+    case EFFECT_CMD_SET_VOLUME:
+    case EFFECT_CMD_SET_AUDIO_MODE:
+        break;
+
+    default:
+        ALOGW("LE_command invalid command %d",cmdCode);
+        return -EINVAL;
+    }
+
+    return 0;
+}
+
+/* Effect Control Interface Implementation: get_descriptor */
+int LE_getDescriptor(effect_handle_t   self,
+                                    effect_descriptor_t *pDescriptor)
+{
+    LoudnessEnhancerContext * pContext = (LoudnessEnhancerContext *) self;
+
+    if (pContext == NULL || pDescriptor == NULL) {
+        ALOGV("LE_getDescriptor() invalid param");
+        return -EINVAL;
+    }
+
+    *pDescriptor = gLEDescriptor;
+
+    return 0;
+}   /* end LE_getDescriptor */
+
+// effect_handle_t interface implementation for DRC effect
+const struct effect_interface_s gLEInterface = {
+        LE_process,
+        LE_command,
+        LE_getDescriptor,
+        NULL,
+};
+
+// This is the only symbol that needs to be exported
+__attribute__ ((visibility ("default")))
+audio_effect_library_t AUDIO_EFFECT_LIBRARY_INFO_SYM = {
+    tag : AUDIO_EFFECT_LIBRARY_TAG,
+    version : EFFECT_LIBRARY_API_VERSION,
+    name : "Loudness Enhancer Library",
+    implementor : "The Android Open Source Project",
+    create_effect : LELib_Create,
+    release_effect : LELib_Release,
+    get_descriptor : LELib_GetDescriptor,
+};
+
+}; // extern "C"
+
diff --git a/media/libeffects/loudness/MODULE_LICENSE_APACHE2 b/media/libeffects/loudness/MODULE_LICENSE_APACHE2
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/media/libeffects/loudness/MODULE_LICENSE_APACHE2
diff --git a/media/libeffects/loudness/NOTICE b/media/libeffects/loudness/NOTICE
new file mode 100644
index 0000000..ad6ed94
--- /dev/null
+++ b/media/libeffects/loudness/NOTICE
@@ -0,0 +1,190 @@
+
+   Copyright (c) 2013, 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.
+
+   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.
+
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
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+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
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+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
diff --git a/media/libeffects/loudness/common/core/basic_types.h b/media/libeffects/loudness/common/core/basic_types.h
new file mode 100644
index 0000000..593e914
--- /dev/null
+++ b/media/libeffects/loudness/common/core/basic_types.h
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef LE_FX_ENGINE_COMMON_CORE_BASIC_TYPES_H_
+#define LE_FX_ENGINE_COMMON_CORE_BASIC_TYPES_H_
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string>
+using ::std::string;
+using ::std::basic_string;
+#include <vector>
+using ::std::vector;
+
+#include "common/core/os.h"
+
+// -----------------------------------------------------------------------------
+// Definitions of common basic types:
+// -----------------------------------------------------------------------------
+
+#if !defined(G_COMPILE) && !defined(BASE_INTEGRAL_TYPES_H_)
+
+namespace le_fx {
+
+typedef signed char         schar;
+typedef signed char         int8;
+typedef short               int16;
+typedef int                 int32;
+typedef long long           int64;
+
+typedef unsigned char       uint8;
+typedef unsigned short      uint16;
+typedef unsigned int        uint32;
+typedef unsigned long long  uint64;
+
+}  // namespace le_fx
+
+#endif
+
+namespace le_fx {
+
+struct FloatArray {
+  int length;
+  float *data;
+
+  FloatArray(void) {
+    data = NULL;
+    length = 0;
+  }
+};
+
+struct Int16Array {
+  int length;
+  int16 *data;
+
+  Int16Array(void) {
+    data = NULL;
+    length = 0;
+  }
+};
+
+struct Int32Array {
+  int length;
+  int32 *data;
+
+  Int32Array(void) {
+    data = NULL;
+    length = 0;
+  }
+};
+
+struct Int8Array {
+  int length;
+  uint8 *data;
+
+  Int8Array(void) {
+    data = NULL;
+    length = 0;
+  }
+};
+
+//
+// Simple wrapper for waveform data:
+//
+class WaveData : public vector<int16> {
+ public:
+  WaveData();
+  ~WaveData();
+
+  void Set(int number_samples, int sampling_rate, int16 *data);
+  int sample_rate(void) const;
+  void set_sample_rate(int sample_rate);
+  bool Equals(const WaveData &wave_data, int threshold = 0) const;
+
+ private:
+  int sample_rate_;
+};
+
+}  // namespace le_fx
+
+#endif  // LE_FX_ENGINE_COMMON_CORE_BASIC_TYPES_H_
diff --git a/media/libeffects/loudness/common/core/byte_swapper.h b/media/libeffects/loudness/common/core/byte_swapper.h
new file mode 100644
index 0000000..8f0caf3
--- /dev/null
+++ b/media/libeffects/loudness/common/core/byte_swapper.h
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef LE_FX_ENGINE_COMMON_CORE_BYTE_SWAPPER_H_
+#define LE_FX_ENGINE_COMMON_CORE_BYTE_SWAPPER_H_
+
+#include <stdio.h>
+#include <string.h>
+
+#include "common/core/basic_types.h"
+#include "common/core/os.h"
+
+namespace le_fx {
+
+namespace arch {
+
+inline bool IsLittleEndian(void) {
+  int16 word = 1;
+  char *cp = reinterpret_cast<char *>(&word);
+  return cp[0] != 0;
+}
+
+inline bool IsBigEndian(void) {
+  return !IsLittleEndian();
+}
+
+template <typename T, unsigned int kValSize>
+struct ByteSwapper {
+  static T Swap(const T &val) {
+    T new_val = val;
+    char *first = &new_val, *last = first + kValSize - 1, x;
+    for (; first < last; ++first, --last) {
+      x = *last;
+      *last = *first;
+      *first = x;
+    }
+    return new_val;
+  }
+};
+
+template <typename T>
+struct ByteSwapper<T, 1> {
+  static T Swap(const T &val) {
+    return val;
+  }
+};
+
+template <typename T>
+struct ByteSwapper<T, 2> {
+  static T Swap(const T &val) {
+    T new_val;
+    const char *o = (const char *)&val;
+    char *p = reinterpret_cast<char *>(&new_val);
+    p[0] = o[1];
+    p[1] = o[0];
+    return new_val;
+  }
+};
+
+template <typename T>
+struct ByteSwapper<T, 4> {
+  static T Swap(const T &val) {
+    T new_val;
+    const char *o = (const char *)&val;
+    char *p = reinterpret_cast<char *>(&new_val);
+    p[0] = o[3];
+    p[1] = o[2];
+    p[2] = o[1];
+    p[3] = o[0];
+    return new_val;
+  }
+};
+
+template <typename T>
+struct ByteSwapper<T, 8> {
+  static T Swap(const T &val) {
+    T new_val = val;
+    const char *o = (const char *)&val;
+    char *p = reinterpret_cast<char *>(&new_val);
+    p[0] = o[7];
+    p[1] = o[6];
+    p[2] = o[5];
+    p[3] = o[4];
+    p[4] = o[3];
+    p[5] = o[2];
+    p[6] = o[1];
+    p[7] = o[0];
+    return new_val;
+  }
+};
+
+template <typename T>
+T SwapBytes(const T &val, bool force_swap) {
+  if (force_swap) {
+#if !defined(LE_FX__NEED_BYTESWAP)
+    return ByteSwapper<T, sizeof(T)>::Swap(val);
+#else
+    return val;
+#endif  // !LE_FX_NEED_BYTESWAP
+  } else {
+#if !defined(LE_FX_NEED_BYTESWAP)
+    return val;
+#else
+    return ByteSwapper<T, sizeof(T)>::Swap(val);
+#endif  // !LE_FX_NEED_BYTESWAP
+  }
+}
+
+template <typename T>
+const T *SwapBytes(const T *vals, unsigned int num_items, bool force_swap) {
+  if (force_swap) {
+#if !defined(LE_FX_NEED_BYTESWAP)
+    T *writeable_vals = const_cast<T *>(vals);
+    for (unsigned int i = 0; i < num_items; i++) {
+      writeable_vals[i] = ByteSwapper<T, sizeof(T)>::Swap(vals[i]);
+    }
+    return writeable_vals;
+#else
+    return vals;
+#endif  // !LE_FX_NEED_BYTESWAP
+  } else {
+#if !defined(LE_FX_NEED_BYTESWAP)
+    return vals;
+#else
+    T *writeable_vals = const_cast<T *>(vals);
+    for (unsigned int i = 0; i < num_items; i++) {
+      writeable_vals[i] = ByteSwapper<T, sizeof(T)>::Swap(vals[i]);
+    }
+    return writeable_vals;
+#endif  // !LE_FX_NEED_BYTESWAP
+  }
+}
+
+}  // namespace arch
+
+}  // namespace le_fx
+
+#endif  // LE_FX_ENGINE_COMMON_CORE_BYTE_SWAPPER_H_
diff --git a/media/libeffects/loudness/common/core/math.h b/media/libeffects/loudness/common/core/math.h
new file mode 100644
index 0000000..3f302cc
--- /dev/null
+++ b/media/libeffects/loudness/common/core/math.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef LE_FX_ENGINE_COMMON_CORE_MATH_H_
+#define LE_FX_ENGINE_COMMON_CORE_MATH_H_
+
+#include <math.h>
+#include <algorithm>
+using ::std::min;
+using ::std::max;
+using ::std::fill;
+using ::std::fill_n;using ::std::lower_bound;
+#include <cmath>
+#include <math.h>
+//using ::std::fpclassify;
+
+#include "common/core/os.h"
+#include "common/core/types.h"
+
+namespace le_fx {
+namespace math {
+
+// A fast approximation to log2(.)
+inline float fast_log2(float val) {
+  int* const exp_ptr = reinterpret_cast <int *> (&val);
+  int x = *exp_ptr;
+  const int log_2 = ((x >> 23) & 255) - 128;
+  x &= ~(255 << 23);
+  x += 127 << 23;
+  *exp_ptr = x;
+  val = ((-1.0f / 3) * val + 2) * val - 2.0f / 3;
+  return static_cast<float>(val + log_2);
+}
+
+// A fast approximation to log(.)
+inline float fast_log(float val) {
+  return fast_log2(val) *
+      0.693147180559945286226763982995180413126945495605468750f;
+}
+
+// An approximation of the exp(.) function using a 5-th order Taylor expansion.
+// It's pretty accurate between +-0.1 and accurate to 10e-3 between +-1
+template <typename T>
+inline T ExpApproximationViaTaylorExpansionOrder5(T x) {
+  const T x2 = x * x;
+  const T x3 = x2 * x;
+  const T x4 = x2 * x2;
+  const T x5 = x3 * x2;
+  return 1.0f + x + 0.5f * x2 +
+      0.16666666666666665741480812812369549646973609924316406250f * x3 +
+      0.0416666666666666643537020320309238741174340248107910156250f * x4 +
+      0.008333333333333333217685101601546193705871701240539550781250f * x5;
+}
+
+}  // namespace math
+}  // namespace le_fx
+
+// Math functions missing in Android NDK:
+#if defined(LE_FX_OS_ANDROID)
+
+namespace std {
+
+//
+// Round to the nearest integer: We need this implementation
+// since std::round is missing on android.
+//
+template <typename T>
+inline T round(const T &x) {
+  return static_cast<T>(std::floor(static_cast<double>(x) + 0.5));
+}
+
+}  // namespace std
+
+#endif  // LE_FX_OS_ANDROID
+
+#endif  // LE_FX_ENGINE_COMMON_CORE_MATH_H_
diff --git a/media/libeffects/loudness/common/core/os.h b/media/libeffects/loudness/common/core/os.h
new file mode 100644
index 0000000..4a8ce82
--- /dev/null
+++ b/media/libeffects/loudness/common/core/os.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef LE_FX_ENGINE_COMMON_CORE_OS_H_
+#define LE_FX_ENGINE_COMMON_CORE_OS_H_
+
+// -----------------------------------------------------------------------------
+// OS Identification:
+// -----------------------------------------------------------------------------
+
+#define LE_FX_OS_UNIX
+#if defined(__ANDROID__)
+#    define LE_FX_OS_ANDROID
+#endif  // Android
+
+#endif // LE_FX_ENGINE_COMMON_CORE_OS_H_
diff --git a/media/libeffects/loudness/common/core/types.h b/media/libeffects/loudness/common/core/types.h
new file mode 100644
index 0000000..d1b6c6a
--- /dev/null
+++ b/media/libeffects/loudness/common/core/types.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef LE_FX_ENGINE_COMMON_CORE_TYPES_H_
+#define LE_FX_ENGINE_COMMON_CORE_TYPES_H_
+
+#include "common/core/os.h"
+
+#include "common/core/basic_types.h"
+
+#ifndef LE_FX_DISALLOW_COPY_AND_ASSIGN
+#define LE_FX_DISALLOW_COPY_AND_ASSIGN(TypeName) \
+  TypeName(const TypeName&); \
+  void operator=(const TypeName&)
+#endif  // LE_FX_DISALLOW_COPY_AND_ASSIGN
+
+
+#endif  // LE_FX_ENGINE_COMMON_CORE_TYPES_H_
diff --git a/media/libeffects/loudness/dsp/core/basic-inl.h b/media/libeffects/loudness/dsp/core/basic-inl.h
new file mode 100644
index 0000000..3f77147
--- /dev/null
+++ b/media/libeffects/loudness/dsp/core/basic-inl.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef LE_FX_ENGINE_DSP_CORE_BASIC_INL_H_
+#define LE_FX_ENGINE_DSP_CORE_BASIC_INL_H_
+
+#include <math.h>
+
+namespace le_fx {
+
+namespace sigmod {
+
+template <typename T>
+int SearchIndex(const T x_data[],
+                T x,
+                int start_index,
+                int end_index) {
+  int start = start_index;
+  int end = end_index;
+  while (end > start + 1) {
+    int i = (end + start) / 2;
+    if (x_data[i] > x) {
+      end = i;
+    } else {
+      start = i;
+    }
+  }
+  return start;
+}
+
+}  // namespace sigmod
+
+}  // namespace le_fx
+
+#endif  // LE_FX_ENGINE_DSP_CORE_BASIC_INL_H_
diff --git a/media/libeffects/loudness/dsp/core/basic.h b/media/libeffects/loudness/dsp/core/basic.h
new file mode 100644
index 0000000..27e0a8d
--- /dev/null
+++ b/media/libeffects/loudness/dsp/core/basic.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef LE_FX_ENGINE_DSP_CORE_BASIC_H_
+#define LE_FX_ENGINE_DSP_CORE_BASIC_H_
+
+#include <limits.h>
+#include "common/core/math.h"
+#include "common/core/types.h"
+
+namespace le_fx {
+
+namespace sigmod {
+
+// Searchs for the interval that contains <x> using a divide-and-conquer
+// algorithm.
+// X[]: a vector of sorted values (X[i+1] > X[i])
+// x:   a value
+// StartIndex: the minimum searched index
+// EndIndex: the maximum searched index
+// returns: the index <i> that satisfies: X[i] <= x <= X[i+1] &&
+//          StartIndex <= i <= (EndIndex-1)
+template <typename T>
+int SearchIndex(const T x_data[],
+                T x,
+                int start_index,
+                int end_index);
+
+}  // namespace sigmod
+
+}  // namespace le_fx
+
+#include "dsp/core/basic-inl.h"
+
+#endif  // LE_FX_ENGINE_DSP_CORE_BASIC_H_
diff --git a/media/libeffects/loudness/dsp/core/dynamic_range_compression-inl.h b/media/libeffects/loudness/dsp/core/dynamic_range_compression-inl.h
new file mode 100644
index 0000000..fed8c2a
--- /dev/null
+++ b/media/libeffects/loudness/dsp/core/dynamic_range_compression-inl.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+#ifndef LE_FX_ENGINE_DSP_CORE_DYNAMIC_RANGE_COMPRESSION_INL_H_
+#define LE_FX_ENGINE_DSP_CORE_DYNAMIC_RANGE_COMPRESSION_INL_H_
+
+//#define LOG_NDEBUG 0
+#include <cutils/log.h>
+
+
+namespace le_fx {
+
+
+inline void AdaptiveDynamicRangeCompression::set_knee_threshold(float decibel) {
+  // Converts to 1og-base
+  knee_threshold_in_decibel_ = decibel;
+  knee_threshold_ = 0.1151292546497023061569109358970308676362037658691406250f *
+      decibel + 10.39717719035538401328722102334722876548767089843750f;
+}
+
+
+inline void AdaptiveDynamicRangeCompression::set_knee_threshold_via_target_gain(
+    float target_gain) {
+  const float decibel = target_gain_to_knee_threshold_.Interpolate(
+        target_gain);
+  ALOGE("set_knee_threshold_via_target_gain: decibel =%.3f", decibel);
+  set_knee_threshold(decibel);
+}
+
+}  // namespace le_fx
+
+
+#endif  // LE_FX_ENGINE_DSP_CORE_DYNAMIC_RANGE_COMPRESSION_INL_H_
diff --git a/media/libeffects/loudness/dsp/core/dynamic_range_compression.cpp b/media/libeffects/loudness/dsp/core/dynamic_range_compression.cpp
new file mode 100644
index 0000000..2bbd043
--- /dev/null
+++ b/media/libeffects/loudness/dsp/core/dynamic_range_compression.cpp
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#include <cmath>
+
+#include "common/core/math.h"
+#include "common/core/types.h"
+#include "dsp/core/basic.h"
+#include "dsp/core/interpolation.h"
+#include "dsp/core/dynamic_range_compression.h"
+
+//#define LOG_NDEBUG 0
+#include <cutils/log.h>
+
+
+namespace le_fx {
+
+// Definitions for static const class members declared in
+// dynamic_range_compression.h.
+const float AdaptiveDynamicRangeCompression::kMinAbsValue = 0.000001f;
+const float AdaptiveDynamicRangeCompression::kMinLogAbsValue =
+    0.032766999999999997517097227728299912996590137481689453125f;
+const float AdaptiveDynamicRangeCompression::kFixedPointLimit = 32767.0f;
+const float AdaptiveDynamicRangeCompression::kInverseFixedPointLimit =
+    1.0f / AdaptiveDynamicRangeCompression::kFixedPointLimit;
+const float AdaptiveDynamicRangeCompression::kDefaultKneeThresholdInDecibel =
+    -8.0f;
+const float AdaptiveDynamicRangeCompression::kCompressionRatio = 7.0f;
+const float AdaptiveDynamicRangeCompression::kTauAttack = 0.001f;
+const float AdaptiveDynamicRangeCompression::kTauRelease = 0.015f;
+
+AdaptiveDynamicRangeCompression::AdaptiveDynamicRangeCompression() {
+  static const float kTargetGain[] = {
+      1.0f, 2.0f, 3.0f, 4.0f, 5.0f };
+  static const float kKneeThreshold[] = {
+      -8.0f, -8.0f, -8.5f, -9.0f, -10.0f };
+  target_gain_to_knee_threshold_.Initialize(
+      &kTargetGain[0], &kKneeThreshold[0],
+      sizeof(kTargetGain) / sizeof(kTargetGain[0]));
+}
+
+bool AdaptiveDynamicRangeCompression::Initialize(
+        float target_gain, float sampling_rate) {
+  set_knee_threshold_via_target_gain(target_gain);
+  sampling_rate_ = sampling_rate;
+  state_ = 0.0f;
+  compressor_gain_ = 1.0f;
+  if (kTauAttack > 0.0f) {
+    const float taufs = kTauAttack * sampling_rate_;
+    alpha_attack_ = std::exp(-1.0f / taufs);
+  } else {
+    alpha_attack_ = 0.0f;
+  }
+  if (kTauRelease > 0.0f) {
+    const float taufs = kTauRelease * sampling_rate_;
+    alpha_release_ = std::exp(-1.0f / taufs);
+  } else {
+    alpha_release_ = 0.0f;
+  }
+  // Feed-forward topology
+  slope_ = 1.0f / kCompressionRatio - 1.0f;
+  return true;
+}
+
+float AdaptiveDynamicRangeCompression::Compress(float x) {
+  const float max_abs_x = std::max(std::fabs(x), kMinLogAbsValue);
+  const float max_abs_x_dB = math::fast_log(max_abs_x);
+  // Subtract Threshold from log-encoded input to get the amount of overshoot
+  const float overshoot = max_abs_x_dB - knee_threshold_;
+  // Hard half-wave rectifier
+  const float rect = std::max(overshoot, 0.0f);
+  // Multiply rectified overshoot with slope
+  const float cv = rect * slope_;
+  const float prev_state = state_;
+  if (cv <= state_) {
+    state_ = alpha_attack_ * state_ + (1.0f - alpha_attack_) * cv;
+  } else {
+    state_ = alpha_release_ * state_ + (1.0f - alpha_release_) * cv;
+  }
+  compressor_gain_ *=
+      math::ExpApproximationViaTaylorExpansionOrder5(state_ - prev_state);
+  x *= compressor_gain_;
+  if (x > kFixedPointLimit) {
+    return kFixedPointLimit;
+  }
+  if (x < -kFixedPointLimit) {
+    return -kFixedPointLimit;
+  }
+  return x;
+}
+
+}  // namespace le_fx
+
diff --git a/media/libeffects/loudness/dsp/core/dynamic_range_compression.h b/media/libeffects/loudness/dsp/core/dynamic_range_compression.h
new file mode 100644
index 0000000..4c015df
--- /dev/null
+++ b/media/libeffects/loudness/dsp/core/dynamic_range_compression.h
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+#ifndef LE_FX_ENGINE_DSP_CORE_DYNAMIC_RANGE_COMPRESSION_H_
+#define LE_FX_ENGINE_DSP_CORE_DYNAMIC_RANGE_COMPRESSION_H_
+
+#include "common/core/types.h"
+#include "common/core/math.h"
+#include "dsp/core/basic.h"
+#include "dsp/core/interpolation.h"
+
+//#define LOG_NDEBUG 0
+#include <cutils/log.h>
+
+
+namespace le_fx {
+
+// An adaptive dynamic range compression algorithm. The gain adaptation is made
+// at the logarithmic domain and it is based on a Branching-Smooth compensated
+// digital peak detector with different time constants for attack and release.
+class AdaptiveDynamicRangeCompression {
+ public:
+    AdaptiveDynamicRangeCompression();
+
+    // Initializes the compressor using prior information. It assumes that the
+    // input signal is speech from high-quality recordings that is scaled and then
+    // fed to the compressor. The compressor is tuned according to the target gain
+    // that is expected to be applied.
+    //
+    // Target gain receives values between 0.0 and 10.0. The knee threshold is
+    // reduced as the target gain increases in order to fit the increased range of
+    // values.
+    //
+    // Values between 1.0 and 2.0 will only mildly affect your signal. Higher
+    // values will reduce the dynamic range of the signal to the benefit of
+    // increased loudness.
+    //
+    // If nothing is known regarding the input, a `target_gain` of 1.0f is a
+    // relatively safe choice for many signals.
+    bool Initialize(float target_gain, float sampling_rate);
+
+  // A fast version of the algorithm that uses approximate computations for the
+  // log(.) and exp(.).
+  float Compress(float x);
+
+  // This version is slower than Compress(.) but faster than CompressSlow(.)
+  float CompressNormalSpeed(float x);
+
+  // A slow version of the algorithm that is easier for further developement,
+  // tuning and debugging
+  float CompressSlow(float x);
+
+  // Sets knee threshold (in decibel).
+  void set_knee_threshold(float decibel);
+
+  // Sets knee threshold via the target gain using an experimentally derived
+  // relationship.
+  void set_knee_threshold_via_target_gain(float target_gain);
+
+ private:
+  // The minimum accepted absolute input value and it's natural logarithm. This
+  // is to prevent numerical issues when the input is close to zero
+  static const float kMinAbsValue;
+  static const float kMinLogAbsValue;
+  // Fixed-point arithmetic limits
+  static const float kFixedPointLimit;
+  static const float kInverseFixedPointLimit;
+  // The default knee threshold in decibel. The knee threshold defines when the
+  // compressor is actually starting to compress the value of the input samples
+  static const float kDefaultKneeThresholdInDecibel;
+  // The compression ratio is the reciprocal of the slope of the line segment
+  // above the threshold (in the log-domain). The ratio controls the
+  // effectiveness of the compression.
+  static const float kCompressionRatio;
+  // The attack time of the envelope detector
+  static const float kTauAttack;
+  // The release time of the envelope detector
+  static const float kTauRelease;
+
+  float sampling_rate_;
+  // the internal state of the envelope detector
+  float state_;
+  // the latest gain factor that was applied to the input signal
+  float compressor_gain_;
+  // attack constant for exponential dumping
+  float alpha_attack_;
+  // release constant for exponential dumping
+  float alpha_release_;
+  float slope_;
+  // The knee threshold
+  float knee_threshold_;
+  float knee_threshold_in_decibel_;
+  // This interpolator provides the function that relates target gain to knee
+  // threshold.
+  sigmod::InterpolatorLinear<float> target_gain_to_knee_threshold_;
+
+  LE_FX_DISALLOW_COPY_AND_ASSIGN(AdaptiveDynamicRangeCompression);
+};
+
+}  // namespace le_fx
+
+#include "dsp/core/dynamic_range_compression-inl.h"
+
+#endif  // LE_FX_ENGINE_DSP_CORE_DYNAMIC_RANGE_COMPRESSION_H_
diff --git a/media/libeffects/loudness/dsp/core/interpolation.h b/media/libeffects/loudness/dsp/core/interpolation.h
new file mode 100644
index 0000000..23c287c
--- /dev/null
+++ b/media/libeffects/loudness/dsp/core/interpolation.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+#ifndef LE_FX_ENGINE_DSP_CORE_INTERPOLATION_H_
+#define LE_FX_ENGINE_DSP_CORE_INTERPOLATION_H_
+
+#include "common/core/math.h"
+#include "dsp/core/interpolator_base.h"
+#include "dsp/core/interpolator_linear.h"
+
+#endif  // LE_FX_ENGINE_DSP_CORE_INTERPOLATION_H_
+
diff --git a/media/libeffects/loudness/dsp/core/interpolator_base-inl.h b/media/libeffects/loudness/dsp/core/interpolator_base-inl.h
new file mode 100644
index 0000000..bd08b65
--- /dev/null
+++ b/media/libeffects/loudness/dsp/core/interpolator_base-inl.h
@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef LE_FX_ENGINE_DSP_CORE_INTERPOLATOR_BASE_INL_H_
+#define LE_FX_ENGINE_DSP_CORE_INTERPOLATOR_BASE_INL_H_
+
+#include "dsp/core/basic.h"
+
+//#define LOG_NDEBUG 0
+#include <cutils/log.h>
+
+
+namespace le_fx {
+
+namespace sigmod {
+
+template <typename T, class Algorithm>
+InterpolatorBase<T, Algorithm>::InterpolatorBase() {
+  status_ = false;
+  cached_index_ = 0;
+  x_data_ = NULL;
+  y_data_ = NULL;
+  data_length_ = 0;
+  own_x_data_ = false;
+  x_start_offset_ = 0.0;
+  last_element_index_ = -1;
+  x_inverse_sampling_interval_ = 0.0;
+  state_ = NULL;
+}
+
+template <typename T, class Algorithm>
+InterpolatorBase<T, Algorithm>::~InterpolatorBase() {
+  delete [] state_;
+  if (own_x_data_) {
+    delete [] x_data_;
+  }
+}
+
+template <typename T, class Algorithm>
+bool InterpolatorBase<T, Algorithm>::Initialize(const vector<T> &x_data,
+                                                const vector<T> &y_data) {
+#ifndef NDEBUG
+  if (x_data.size() != y_data.size()) {
+    LoggerError("InterpolatorBase::Initialize: xData size (%d) != yData size"
+                  " (%d)", x_data.size(), y_data.size());
+  }
+#endif
+  return Initialize(&x_data[0], &y_data[0], x_data.size());
+}
+
+template <typename T, class Algorithm>
+bool InterpolatorBase<T, Algorithm>::Initialize(double x_start_offset,
+                                                double x_sampling_interval,
+                                                const vector<T> &y_data) {
+  return Initialize(x_start_offset,
+                    x_sampling_interval,
+                    &y_data[0],
+                    y_data.size());
+}
+
+template <typename T, class Algorithm>
+bool InterpolatorBase<T, Algorithm>::Initialize(double x_start_offset,
+                                                double x_sampling_interval,
+                                                const T *y_data,
+                                                int data_length) {
+  // Constructs and populate x-axis data: `x_data_`
+  T *x_data_tmp = new T[data_length];
+  float time_offset = x_start_offset;
+  for (int n = 0; n < data_length; n++) {
+    x_data_tmp[n] = time_offset;
+    time_offset += x_sampling_interval;
+  }
+  Initialize(x_data_tmp, y_data, data_length);
+  // Sets-up the regularly sampled interpolation mode
+  x_start_offset_ = x_start_offset;
+  x_inverse_sampling_interval_ = 1.0 / x_sampling_interval;
+  own_x_data_ = true;
+  return status_;
+}
+
+
+template <typename T, class Algorithm>
+bool InterpolatorBase<T, Algorithm>::Initialize(
+    const T *x_data, const T *y_data, int data_length) {
+  // Default settings
+  cached_index_ = 0;
+  data_length_ = 0;
+  x_start_offset_ = 0;
+  x_inverse_sampling_interval_ = 0;
+  state_ = NULL;
+  // Input data is externally owned
+  own_x_data_ = false;
+  x_data_ = x_data;
+  y_data_ = y_data;
+  data_length_ = data_length;
+  last_element_index_ = data_length - 1;
+  // Check input data sanity
+  for (int n = 0; n < last_element_index_; ++n) {
+    if (x_data_[n + 1] <= x_data_[n]) {
+      ALOGE("InterpolatorBase::Initialize: xData are not ordered or "
+              "contain equal values (X[%d] <= X[%d]) (%.5e <= %.5e)",
+              n + 1, n, x_data_[n + 1], x_data_[n]);
+      status_ = false;
+      return false;
+    }
+  }
+  // Pre-compute internal state by calling the corresponding function of the
+  // derived class.
+  status_ = static_cast<Algorithm*>(this)->SetInternalState();
+  return status_;
+}
+
+template <typename T, class Algorithm>
+T InterpolatorBase<T, Algorithm>::Interpolate(T x) {
+#ifndef NDEBUG
+  if (cached_index_ < 0 || cached_index_ > data_length_ - 2) {
+    LoggerError("InterpolatorBase:Interpolate: CachedIndex_ out of bounds "
+                  "[0, %d, %d]", cached_index_, data_length_ - 2);
+  }
+#endif
+  // Search for the containing interval
+  if (x <= x_data_[cached_index_]) {
+    if (cached_index_ <= 0) {
+      cached_index_ = 0;
+      return y_data_[0];
+    }
+    if (x >= x_data_[cached_index_ - 1]) {
+      cached_index_--;  // Fast descending
+    } else {
+      if (x <= x_data_[0]) {
+        cached_index_ = 0;
+        return y_data_[0];
+      }
+      cached_index_ = SearchIndex(x_data_, x, 0, cached_index_);
+    }
+  } else {
+    if (cached_index_ >= last_element_index_) {
+      cached_index_ = last_element_index_;
+      return y_data_[last_element_index_];
+    }
+    if (x > x_data_[cached_index_ + 1]) {
+      if (cached_index_ + 2 > last_element_index_) {
+        cached_index_ = last_element_index_ - 1;
+        return y_data_[last_element_index_];
+      }
+      if (x <= x_data_[cached_index_ + 2]) {
+        cached_index_++;  // Fast ascending
+      } else {
+        if (x >= x_data_[last_element_index_]) {
+          cached_index_ = last_element_index_ - 1;
+          return y_data_[last_element_index_];
+        }
+        cached_index_ = SearchIndex(
+            x_data_, x, cached_index_, last_element_index_);
+      }
+    }
+  }
+  // Compute interpolated value by calling the corresponding function of the
+  // derived class.
+  return static_cast<Algorithm*>(this)->MethodSpecificInterpolation(x);
+}
+
+}  // namespace sigmod
+
+}  // namespace le_fx
+
+#endif  // LE_FX_ENGINE_DSP_CORE_INTERPOLATOR_BASE_INL_H_
diff --git a/media/libeffects/loudness/dsp/core/interpolator_base.h b/media/libeffects/loudness/dsp/core/interpolator_base.h
new file mode 100644
index 0000000..0cd1a35
--- /dev/null
+++ b/media/libeffects/loudness/dsp/core/interpolator_base.h
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef LE_FX_ENGINE_DSP_CORE_INTERPOLATOR_BASE_H_
+#define LE_FX_ENGINE_DSP_CORE_INTERPOLATOR_BASE_H_
+
+#include "common/core/types.h"
+
+namespace le_fx {
+
+namespace sigmod {
+
+// Interpolation base-class that provides the interface, while it is the derived
+// class that provides the specific interpolation algorithm. The following list
+// of interpolation algorithms are currently present:
+//
+// InterpolationSine<T>: weighted interpolation between y_data[n] and
+//                       y_data[n+1] using a sin(.) weighting factor from
+//                       0 to pi/4.
+// InterpolationLinear<T>: linear interpolation
+// InterpolationSplines<T>: spline-based interpolation
+//
+// Example (using derived spline-based interpolation class):
+//  InterpolatorSplines<float> interp(x_data, y_data, data_length);
+//  for (int n = 0; n < data_length; n++) Y[n] = interp.Interpolate(X[n]);
+//
+template <typename T, class Algorithm>
+class InterpolatorBase {
+ public:
+  InterpolatorBase();
+  ~InterpolatorBase();
+
+  // Generic random-access interpolation with arbitrary spaced x-axis samples.
+  // Below X[0], the interpolator returns Y[0]. Above X[data_length-1], it
+  // returns Y[data_length-1].
+  T Interpolate(T x);
+
+  bool get_status() const {
+    return status_;
+  }
+
+  // Initializes internal buffers.
+  //  x_data: [(data_length)x1] x-axis coordinates (searching axis)
+  //  y_data: [(data_length)x1] y-axis coordinates (interpolation axis)
+  //  data_length: number of points
+  // returns `true` if everything is ok, `false`, otherwise
+  bool Initialize(const T *x_data, const T *y_data, int data_length);
+
+  // Initializes internal buffers.
+  //  x_data: x-axis coordinates (searching axis)
+  //  y_data: y-axis coordinates (interpolating axis)
+  // returns `true` if everything is ok, `false`, otherwise
+  bool Initialize(const vector<T> &x_data, const vector<T> &y_data);
+
+  // Initialization for regularly sampled sequences, where:
+  //  x_data[i] = x_start_offset + i * x_sampling_interval
+  bool Initialize(double x_start_offset,
+                  double x_sampling_interval,
+                  const vector<T> &y_data);
+
+  // Initialization for regularly sampled sequences, where:
+  //  x_data[i] = x_start_offset + i * x_sampling_interval
+  bool Initialize(double x_start_offset,
+                  double x_sampling_interval,
+                  const T *y_data,
+                  int data_length);
+
+ protected:
+  // Is set to false if something goes wrong, and to true if everything is ok.
+  bool status_;
+
+  // The start-index of the previously searched interval
+  int cached_index_;
+
+  // Data points
+  const T *x_data_;  // Externally or internally owned, depending on own_x_data_
+  const T *y_data_;  // Externally owned (always)
+  int data_length_;
+  // Index of the last element `data_length_ - 1` kept here for optimization
+  int last_element_index_;
+  bool own_x_data_;
+  // For regularly-samples sequences, keep only the boundaries and the intervals
+  T x_start_offset_;
+  float x_inverse_sampling_interval_;
+
+  // Algorithm state (internally owned)
+  double *state_;
+
+ private:
+  LE_FX_DISALLOW_COPY_AND_ASSIGN(InterpolatorBase);
+};
+
+}  // namespace sigmod
+
+}  // namespace le_fx
+
+#include "dsp/core/interpolator_base-inl.h"
+
+#endif  // LE_FX_ENGINE_DSP_CORE_INTERPOLATOR_BASE_H_
diff --git a/media/libeffects/loudness/dsp/core/interpolator_linear.h b/media/libeffects/loudness/dsp/core/interpolator_linear.h
new file mode 100644
index 0000000..434698a
--- /dev/null
+++ b/media/libeffects/loudness/dsp/core/interpolator_linear.h
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef LE_FX_ENGINE_DSP_CORE_INTERPOLATOR_LINEAR_H_
+#define LE_FX_ENGINE_DSP_CORE_INTERPOLATOR_LINEAR_H_
+
+#include <math.h>
+#include "dsp/core/interpolator_base.h"
+
+namespace le_fx {
+
+namespace sigmod {
+
+// Linear interpolation class.
+//
+// The main functionality of this class is provided by it's base-class, so
+// please refer to: InterpolatorBase
+//
+// Example:
+//  InterpolatorLinear<float> interp(x_data, y_data, data_length);
+//  for (int n = 0; n < data_length; n++) Y[n] = interp.Interpolate(X[n]);
+//
+template <typename T>
+class InterpolatorLinear: public InterpolatorBase<T, InterpolatorLinear<T> > {
+ public:
+  InterpolatorLinear() { }
+  ~InterpolatorLinear() { }
+
+ protected:
+  // Provides the main implementation of the linear interpolation algorithm.
+  // Assumes that: X[cached_index_] < x < X[cached_index_ + 1]
+  T MethodSpecificInterpolation(T x);
+
+  // Pre-compute internal state_ parameters.
+  bool SetInternalState();
+
+ private:
+  friend class InterpolatorBase<T, InterpolatorLinear<T> >;
+  typedef InterpolatorBase<T, InterpolatorLinear<T> > BaseClass;
+  using BaseClass::status_;
+  using BaseClass::cached_index_;
+  using BaseClass::x_data_;
+  using BaseClass::y_data_;
+  using BaseClass::data_length_;
+  using BaseClass::state_;
+
+  LE_FX_DISALLOW_COPY_AND_ASSIGN(InterpolatorLinear<T>);
+};
+
+template <typename T>
+inline T InterpolatorLinear<T>::MethodSpecificInterpolation(T x) {
+  T dX = x_data_[cached_index_ + 1] - x_data_[cached_index_];
+  T dY = y_data_[cached_index_ + 1] - y_data_[cached_index_];
+  T dx = x - x_data_[cached_index_];
+  return y_data_[cached_index_] + (dY * dx) / dX;
+}
+
+template <typename T>
+bool InterpolatorLinear<T>::SetInternalState() {
+  state_ = NULL;
+  return true;
+}
+
+}  // namespace sigmod
+
+}  // namespace le_fx
+
+#endif  // LE_FX_ENGINE_DSP_CORE_INTERPOLATOR_LINEAR_H_