diff --git a/services/audioflinger/Android.mk b/services/audioflinger/Android.mk
index fee2347..f8446ac 100644
--- a/services/audioflinger/Android.mk
+++ b/services/audioflinger/Android.mk
@@ -44,9 +44,9 @@
     SpdifStreamOut.cpp          \
     Effects.cpp                 \
     AudioMixer.cpp.arm          \
-    PatchPanel.cpp
-
-LOCAL_SRC_FILES += StateQueue.cpp
+    BufferProviders.cpp         \
+    PatchPanel.cpp              \
+    StateQueue.cpp
 
 LOCAL_C_INCLUDES := \
     $(TOPDIR)frameworks/av/services/audiopolicy \
diff --git a/services/audioflinger/AudioMixer.cpp b/services/audioflinger/AudioMixer.cpp
index dddca02..cb90ece 100644
--- a/services/audioflinger/AudioMixer.cpp
+++ b/services/audioflinger/AudioMixer.cpp
@@ -38,9 +38,7 @@
 #include <audio_utils/format.h>
 #include <common_time/local_clock.h>
 #include <common_time/cc_helper.h>
-
-#include <media/EffectsFactoryApi.h>
-#include <audio_effects/effect_downmix.h>
+#include <media/AudioResamplerPublic.h>
 
 #include "AudioMixerOps.h"
 #include "AudioMixer.h"
@@ -91,323 +89,6 @@
     return a < b ? a : b;
 }
 
-AudioMixer::CopyBufferProvider::CopyBufferProvider(size_t inputFrameSize,
-        size_t outputFrameSize, size_t bufferFrameCount) :
-        mInputFrameSize(inputFrameSize),
-        mOutputFrameSize(outputFrameSize),
-        mLocalBufferFrameCount(bufferFrameCount),
-        mLocalBufferData(NULL),
-        mConsumed(0)
-{
-    ALOGV("CopyBufferProvider(%p)(%zu, %zu, %zu)", this,
-            inputFrameSize, outputFrameSize, bufferFrameCount);
-    LOG_ALWAYS_FATAL_IF(inputFrameSize < outputFrameSize && bufferFrameCount == 0,
-            "Requires local buffer if inputFrameSize(%zu) < outputFrameSize(%zu)",
-            inputFrameSize, outputFrameSize);
-    if (mLocalBufferFrameCount) {
-        (void)posix_memalign(&mLocalBufferData, 32, mLocalBufferFrameCount * mOutputFrameSize);
-    }
-    mBuffer.frameCount = 0;
-}
-
-AudioMixer::CopyBufferProvider::~CopyBufferProvider()
-{
-    ALOGV("~CopyBufferProvider(%p)", this);
-    if (mBuffer.frameCount != 0) {
-        mTrackBufferProvider->releaseBuffer(&mBuffer);
-    }
-    free(mLocalBufferData);
-}
-
-status_t AudioMixer::CopyBufferProvider::getNextBuffer(AudioBufferProvider::Buffer *pBuffer,
-        int64_t pts)
-{
-    //ALOGV("CopyBufferProvider(%p)::getNextBuffer(%p (%zu), %lld)",
-    //        this, pBuffer, pBuffer->frameCount, pts);
-    if (mLocalBufferFrameCount == 0) {
-        status_t res = mTrackBufferProvider->getNextBuffer(pBuffer, pts);
-        if (res == OK) {
-            copyFrames(pBuffer->raw, pBuffer->raw, pBuffer->frameCount);
-        }
-        return res;
-    }
-    if (mBuffer.frameCount == 0) {
-        mBuffer.frameCount = pBuffer->frameCount;
-        status_t res = mTrackBufferProvider->getNextBuffer(&mBuffer, pts);
-        // At one time an upstream buffer provider had
-        // res == OK and mBuffer.frameCount == 0, doesn't seem to happen now 7/18/2014.
-        //
-        // By API spec, if res != OK, then mBuffer.frameCount == 0.
-        // but there may be improper implementations.
-        ALOG_ASSERT(res == OK || mBuffer.frameCount == 0);
-        if (res != OK || mBuffer.frameCount == 0) { // not needed by API spec, but to be safe.
-            pBuffer->raw = NULL;
-            pBuffer->frameCount = 0;
-            return res;
-        }
-        mConsumed = 0;
-    }
-    ALOG_ASSERT(mConsumed < mBuffer.frameCount);
-    size_t count = min(mLocalBufferFrameCount, mBuffer.frameCount - mConsumed);
-    count = min(count, pBuffer->frameCount);
-    pBuffer->raw = mLocalBufferData;
-    pBuffer->frameCount = count;
-    copyFrames(pBuffer->raw, (uint8_t*)mBuffer.raw + mConsumed * mInputFrameSize,
-            pBuffer->frameCount);
-    return OK;
-}
-
-void AudioMixer::CopyBufferProvider::releaseBuffer(AudioBufferProvider::Buffer *pBuffer)
-{
-    //ALOGV("CopyBufferProvider(%p)::releaseBuffer(%p(%zu))",
-    //        this, pBuffer, pBuffer->frameCount);
-    if (mLocalBufferFrameCount == 0) {
-        mTrackBufferProvider->releaseBuffer(pBuffer);
-        return;
-    }
-    // LOG_ALWAYS_FATAL_IF(pBuffer->frameCount == 0, "Invalid framecount");
-    mConsumed += pBuffer->frameCount; // TODO: update for efficiency to reuse existing content
-    if (mConsumed != 0 && mConsumed >= mBuffer.frameCount) {
-        mTrackBufferProvider->releaseBuffer(&mBuffer);
-        ALOG_ASSERT(mBuffer.frameCount == 0);
-    }
-    pBuffer->raw = NULL;
-    pBuffer->frameCount = 0;
-}
-
-void AudioMixer::CopyBufferProvider::reset()
-{
-    if (mBuffer.frameCount != 0) {
-        mTrackBufferProvider->releaseBuffer(&mBuffer);
-    }
-    mConsumed = 0;
-}
-
-AudioMixer::DownmixerBufferProvider::DownmixerBufferProvider(
-        audio_channel_mask_t inputChannelMask,
-        audio_channel_mask_t outputChannelMask, audio_format_t format,
-        uint32_t sampleRate, int32_t sessionId, size_t bufferFrameCount) :
-        CopyBufferProvider(
-            audio_bytes_per_sample(format) * audio_channel_count_from_out_mask(inputChannelMask),
-            audio_bytes_per_sample(format) * audio_channel_count_from_out_mask(outputChannelMask),
-            bufferFrameCount)  // set bufferFrameCount to 0 to do in-place
-{
-    ALOGV("DownmixerBufferProvider(%p)(%#x, %#x, %#x %u %d)",
-            this, inputChannelMask, outputChannelMask, format,
-            sampleRate, sessionId);
-    if (!sIsMultichannelCapable
-            || EffectCreate(&sDwnmFxDesc.uuid,
-                    sessionId,
-                    SESSION_ID_INVALID_AND_IGNORED,
-                    &mDownmixHandle) != 0) {
-         ALOGE("DownmixerBufferProvider() error creating downmixer effect");
-         mDownmixHandle = NULL;
-         return;
-     }
-     // channel input configuration will be overridden per-track
-     mDownmixConfig.inputCfg.channels = inputChannelMask;   // FIXME: Should be bits
-     mDownmixConfig.outputCfg.channels = outputChannelMask; // FIXME: should be bits
-     mDownmixConfig.inputCfg.format = format;
-     mDownmixConfig.outputCfg.format = format;
-     mDownmixConfig.inputCfg.samplingRate = sampleRate;
-     mDownmixConfig.outputCfg.samplingRate = sampleRate;
-     mDownmixConfig.inputCfg.accessMode = EFFECT_BUFFER_ACCESS_READ;
-     mDownmixConfig.outputCfg.accessMode = EFFECT_BUFFER_ACCESS_WRITE;
-     // input and output buffer provider, and frame count will not be used as the downmix effect
-     // process() function is called directly (see DownmixerBufferProvider::getNextBuffer())
-     mDownmixConfig.inputCfg.mask = EFFECT_CONFIG_SMP_RATE | EFFECT_CONFIG_CHANNELS |
-             EFFECT_CONFIG_FORMAT | EFFECT_CONFIG_ACC_MODE;
-     mDownmixConfig.outputCfg.mask = mDownmixConfig.inputCfg.mask;
-
-     int cmdStatus;
-     uint32_t replySize = sizeof(int);
-
-     // Configure downmixer
-     status_t status = (*mDownmixHandle)->command(mDownmixHandle,
-             EFFECT_CMD_SET_CONFIG /*cmdCode*/, sizeof(effect_config_t) /*cmdSize*/,
-             &mDownmixConfig /*pCmdData*/,
-             &replySize, &cmdStatus /*pReplyData*/);
-     if (status != 0 || cmdStatus != 0) {
-         ALOGE("DownmixerBufferProvider() error %d cmdStatus %d while configuring downmixer",
-                 status, cmdStatus);
-         EffectRelease(mDownmixHandle);
-         mDownmixHandle = NULL;
-         return;
-     }
-
-     // Enable downmixer
-     replySize = sizeof(int);
-     status = (*mDownmixHandle)->command(mDownmixHandle,
-             EFFECT_CMD_ENABLE /*cmdCode*/, 0 /*cmdSize*/, NULL /*pCmdData*/,
-             &replySize, &cmdStatus /*pReplyData*/);
-     if (status != 0 || cmdStatus != 0) {
-         ALOGE("DownmixerBufferProvider() error %d cmdStatus %d while enabling downmixer",
-                 status, cmdStatus);
-         EffectRelease(mDownmixHandle);
-         mDownmixHandle = NULL;
-         return;
-     }
-
-     // Set downmix type
-     // parameter size rounded for padding on 32bit boundary
-     const int psizePadded = ((sizeof(downmix_params_t) - 1)/sizeof(int) + 1) * sizeof(int);
-     const int downmixParamSize =
-             sizeof(effect_param_t) + psizePadded + sizeof(downmix_type_t);
-     effect_param_t * const param = (effect_param_t *) malloc(downmixParamSize);
-     param->psize = sizeof(downmix_params_t);
-     const downmix_params_t downmixParam = DOWNMIX_PARAM_TYPE;
-     memcpy(param->data, &downmixParam, param->psize);
-     const downmix_type_t downmixType = DOWNMIX_TYPE_FOLD;
-     param->vsize = sizeof(downmix_type_t);
-     memcpy(param->data + psizePadded, &downmixType, param->vsize);
-     replySize = sizeof(int);
-     status = (*mDownmixHandle)->command(mDownmixHandle,
-             EFFECT_CMD_SET_PARAM /* cmdCode */, downmixParamSize /* cmdSize */,
-             param /*pCmdData*/, &replySize, &cmdStatus /*pReplyData*/);
-     free(param);
-     if (status != 0 || cmdStatus != 0) {
-         ALOGE("DownmixerBufferProvider() error %d cmdStatus %d while setting downmix type",
-                 status, cmdStatus);
-         EffectRelease(mDownmixHandle);
-         mDownmixHandle = NULL;
-         return;
-     }
-     ALOGV("DownmixerBufferProvider() downmix type set to %d", (int) downmixType);
-}
-
-AudioMixer::DownmixerBufferProvider::~DownmixerBufferProvider()
-{
-    ALOGV("~DownmixerBufferProvider (%p)", this);
-    EffectRelease(mDownmixHandle);
-    mDownmixHandle = NULL;
-}
-
-void AudioMixer::DownmixerBufferProvider::copyFrames(void *dst, const void *src, size_t frames)
-{
-    mDownmixConfig.inputCfg.buffer.frameCount = frames;
-    mDownmixConfig.inputCfg.buffer.raw = const_cast<void *>(src);
-    mDownmixConfig.outputCfg.buffer.frameCount = frames;
-    mDownmixConfig.outputCfg.buffer.raw = dst;
-    // may be in-place if src == dst.
-    status_t res = (*mDownmixHandle)->process(mDownmixHandle,
-            &mDownmixConfig.inputCfg.buffer, &mDownmixConfig.outputCfg.buffer);
-    ALOGE_IF(res != OK, "DownmixBufferProvider error %d", res);
-}
-
-/* call once in a pthread_once handler. */
-/*static*/ status_t AudioMixer::DownmixerBufferProvider::init()
-{
-    // find multichannel downmix effect if we have to play multichannel content
-    uint32_t numEffects = 0;
-    int ret = EffectQueryNumberEffects(&numEffects);
-    if (ret != 0) {
-        ALOGE("AudioMixer() error %d querying number of effects", ret);
-        return NO_INIT;
-    }
-    ALOGV("EffectQueryNumberEffects() numEffects=%d", numEffects);
-
-    for (uint32_t i = 0 ; i < numEffects ; i++) {
-        if (EffectQueryEffect(i, &sDwnmFxDesc) == 0) {
-            ALOGV("effect %d is called %s", i, sDwnmFxDesc.name);
-            if (memcmp(&sDwnmFxDesc.type, EFFECT_UIID_DOWNMIX, sizeof(effect_uuid_t)) == 0) {
-                ALOGI("found effect \"%s\" from %s",
-                        sDwnmFxDesc.name, sDwnmFxDesc.implementor);
-                sIsMultichannelCapable = true;
-                break;
-            }
-        }
-    }
-    ALOGW_IF(!sIsMultichannelCapable, "unable to find downmix effect");
-    return NO_INIT;
-}
-
-/*static*/ bool AudioMixer::DownmixerBufferProvider::sIsMultichannelCapable = false;
-/*static*/ effect_descriptor_t AudioMixer::DownmixerBufferProvider::sDwnmFxDesc;
-
-AudioMixer::RemixBufferProvider::RemixBufferProvider(audio_channel_mask_t inputChannelMask,
-        audio_channel_mask_t outputChannelMask, audio_format_t format,
-        size_t bufferFrameCount) :
-        CopyBufferProvider(
-                audio_bytes_per_sample(format)
-                    * audio_channel_count_from_out_mask(inputChannelMask),
-                audio_bytes_per_sample(format)
-                    * audio_channel_count_from_out_mask(outputChannelMask),
-                bufferFrameCount),
-        mFormat(format),
-        mSampleSize(audio_bytes_per_sample(format)),
-        mInputChannels(audio_channel_count_from_out_mask(inputChannelMask)),
-        mOutputChannels(audio_channel_count_from_out_mask(outputChannelMask))
-{
-    ALOGV("RemixBufferProvider(%p)(%#x, %#x, %#x) %zu %zu",
-            this, format, inputChannelMask, outputChannelMask,
-            mInputChannels, mOutputChannels);
-
-    const audio_channel_representation_t inputRepresentation =
-            audio_channel_mask_get_representation(inputChannelMask);
-    const audio_channel_representation_t outputRepresentation =
-            audio_channel_mask_get_representation(outputChannelMask);
-    const uint32_t inputBits = audio_channel_mask_get_bits(inputChannelMask);
-    const uint32_t outputBits = audio_channel_mask_get_bits(outputChannelMask);
-
-    switch (inputRepresentation) {
-    case AUDIO_CHANNEL_REPRESENTATION_POSITION:
-        switch (outputRepresentation) {
-        case AUDIO_CHANNEL_REPRESENTATION_POSITION:
-            memcpy_by_index_array_initialization(mIdxAry, ARRAY_SIZE(mIdxAry),
-                    outputBits, inputBits);
-            return;
-        case AUDIO_CHANNEL_REPRESENTATION_INDEX:
-            // TODO: output channel index mask not currently allowed
-            // fall through
-        default:
-            break;
-        }
-        break;
-    case AUDIO_CHANNEL_REPRESENTATION_INDEX:
-        switch (outputRepresentation) {
-        case AUDIO_CHANNEL_REPRESENTATION_POSITION:
-            memcpy_by_index_array_initialization_src_index(mIdxAry, ARRAY_SIZE(mIdxAry),
-                    outputBits, inputBits);
-            return;
-        case AUDIO_CHANNEL_REPRESENTATION_INDEX:
-            // TODO: output channel index mask not currently allowed
-            // fall through
-        default:
-            break;
-        }
-        break;
-    default:
-        break;
-    }
-    LOG_ALWAYS_FATAL("invalid channel mask conversion from %#x to %#x",
-            inputChannelMask, outputChannelMask);
-}
-
-void AudioMixer::RemixBufferProvider::copyFrames(void *dst, const void *src, size_t frames)
-{
-    memcpy_by_index_array(dst, mOutputChannels,
-            src, mInputChannels, mIdxAry, mSampleSize, frames);
-}
-
-AudioMixer::ReformatBufferProvider::ReformatBufferProvider(int32_t channels,
-        audio_format_t inputFormat, audio_format_t outputFormat,
-        size_t bufferFrameCount) :
-        CopyBufferProvider(
-            channels * audio_bytes_per_sample(inputFormat),
-            channels * audio_bytes_per_sample(outputFormat),
-            bufferFrameCount),
-        mChannels(channels),
-        mInputFormat(inputFormat),
-        mOutputFormat(outputFormat)
-{
-    ALOGV("ReformatBufferProvider(%p)(%d, %#x, %#x)", this, channels, inputFormat, outputFormat);
-}
-
-void AudioMixer::ReformatBufferProvider::copyFrames(void *dst, const void *src, size_t frames)
-{
-    memcpy_by_audio_format(dst, mOutputFormat, src, mInputFormat, frames * mChannels);
-}
-
 // ----------------------------------------------------------------------------
 
 // Ensure mConfiguredNames bitmask is initialized properly on all architectures.
diff --git a/services/audioflinger/AudioMixer.h b/services/audioflinger/AudioMixer.h
index 381036b..e283b83 100644
--- a/services/audioflinger/AudioMixer.h
+++ b/services/audioflinger/AudioMixer.h
@@ -29,6 +29,7 @@
 #include <utils/threads.h>
 
 #include "AudioResampler.h"
+#include "BufferProviders.h"
 
 // FIXME This is actually unity gain, which might not be max in future, expressed in U.12
 #define MAX_GAIN_INT AudioMixer::UNITY_GAIN_INT
@@ -159,7 +160,6 @@
 
     struct state_t;
     struct track_t;
-    class CopyBufferProvider;
 
     typedef void (*hook_t)(track_t* t, int32_t* output, size_t numOutFrames, int32_t* temp,
                            int32_t* aux);
@@ -225,11 +225,10 @@
          *    the downmixer requirements to the mixer engine input requirements.
          */
         AudioBufferProvider*     mInputBufferProvider;    // externally provided buffer provider.
-        CopyBufferProvider*      mReformatBufferProvider; // provider wrapper for reformatting.
-        CopyBufferProvider*      downmixerBufferProvider; // wrapper for channel conversion.
-        CopyBufferProvider*      mPostDownmixReformatBufferProvider;
+        PassthruBufferProvider*  mReformatBufferProvider; // provider wrapper for reformatting.
+        PassthruBufferProvider*  downmixerBufferProvider; // wrapper for channel conversion.
+        PassthruBufferProvider*  mPostDownmixReformatBufferProvider;
 
-        // 16-byte boundary
         int32_t     sessionId;
 
         audio_format_t mMixerFormat;     // output mix format: AUDIO_FORMAT_PCM_(FLOAT|16_BIT)
@@ -282,112 +281,6 @@
         track_t         tracks[MAX_NUM_TRACKS] __attribute__((aligned(32)));
     };
 
-    // Base AudioBufferProvider class used for DownMixerBufferProvider, RemixBufferProvider,
-    // and ReformatBufferProvider.
-    // It handles a private buffer for use in converting format or channel masks from the
-    // input data to a form acceptable by the mixer.
-    // TODO: Make a ResamplerBufferProvider when integers are entirely removed from the
-    // processing pipeline.
-    class CopyBufferProvider : public AudioBufferProvider {
-    public:
-        // Use a private buffer of bufferFrameCount frames (each frame is outputFrameSize bytes).
-        // If bufferFrameCount is 0, no private buffer is created and in-place modification of
-        // the upstream buffer provider's buffers is performed by copyFrames().
-        CopyBufferProvider(size_t inputFrameSize, size_t outputFrameSize,
-                size_t bufferFrameCount);
-        virtual ~CopyBufferProvider();
-
-        // Overrides AudioBufferProvider methods
-        virtual status_t getNextBuffer(Buffer* buffer, int64_t pts);
-        virtual void releaseBuffer(Buffer* buffer);
-
-        // Other public methods
-
-        // call this to release the buffer to the upstream provider.
-        // treat it as an audio discontinuity for future samples.
-        virtual void reset();
-
-        // this function should be supplied by the derived class.  It converts
-        // #frames in the *src pointer to the *dst pointer.  It is public because
-        // some providers will allow this to work on arbitrary buffers outside
-        // of the internal buffers.
-        virtual void copyFrames(void *dst, const void *src, size_t frames) = 0;
-
-        // set the upstream buffer provider. Consider calling "reset" before this function.
-        void setBufferProvider(AudioBufferProvider *p) {
-            mTrackBufferProvider = p;
-        }
-
-    protected:
-        AudioBufferProvider* mTrackBufferProvider;
-        const size_t         mInputFrameSize;
-        const size_t         mOutputFrameSize;
-    private:
-        AudioBufferProvider::Buffer mBuffer;
-        const size_t         mLocalBufferFrameCount;
-        void*                mLocalBufferData;
-        size_t               mConsumed;
-    };
-
-    // DownmixerBufferProvider wraps a track AudioBufferProvider to provide
-    // position dependent downmixing by an Audio Effect.
-    class DownmixerBufferProvider : public CopyBufferProvider {
-    public:
-        DownmixerBufferProvider(audio_channel_mask_t inputChannelMask,
-                audio_channel_mask_t outputChannelMask, audio_format_t format,
-                uint32_t sampleRate, int32_t sessionId, size_t bufferFrameCount);
-        virtual ~DownmixerBufferProvider();
-        virtual void copyFrames(void *dst, const void *src, size_t frames);
-        bool isValid() const { return mDownmixHandle != NULL; }
-
-        static status_t init();
-        static bool isMultichannelCapable() { return sIsMultichannelCapable; }
-
-    protected:
-        effect_handle_t    mDownmixHandle;
-        effect_config_t    mDownmixConfig;
-
-        // effect descriptor for the downmixer used by the mixer
-        static effect_descriptor_t sDwnmFxDesc;
-        // indicates whether a downmix effect has been found and is usable by this mixer
-        static bool                sIsMultichannelCapable;
-        // FIXME: should we allow effects outside of the framework?
-        // We need to here. A special ioId that must be <= -2 so it does not map to a session.
-        static const int32_t SESSION_ID_INVALID_AND_IGNORED = -2;
-    };
-
-    // RemixBufferProvider wraps a track AudioBufferProvider to perform an
-    // upmix or downmix to the proper channel count and mask.
-    class RemixBufferProvider : public CopyBufferProvider {
-    public:
-        RemixBufferProvider(audio_channel_mask_t inputChannelMask,
-                audio_channel_mask_t outputChannelMask, audio_format_t format,
-                size_t bufferFrameCount);
-        virtual void copyFrames(void *dst, const void *src, size_t frames);
-
-    protected:
-        const audio_format_t mFormat;
-        const size_t         mSampleSize;
-        const size_t         mInputChannels;
-        const size_t         mOutputChannels;
-        int8_t               mIdxAry[sizeof(uint32_t)*8]; // 32 bits => channel indices
-    };
-
-    // ReformatBufferProvider wraps a track AudioBufferProvider to convert the input data
-    // to an acceptable mixer input format type.
-    class ReformatBufferProvider : public CopyBufferProvider {
-    public:
-        ReformatBufferProvider(int32_t channels,
-                audio_format_t inputFormat, audio_format_t outputFormat,
-                size_t bufferFrameCount);
-        virtual void copyFrames(void *dst, const void *src, size_t frames);
-
-    protected:
-        const int32_t        mChannels;
-        const audio_format_t mInputFormat;
-        const audio_format_t mOutputFormat;
-    };
-
     // bitmask of allocated track names, where bit 0 corresponds to TRACK0 etc.
     uint32_t        mTrackNames;
 
diff --git a/services/audioflinger/BufferProviders.cpp b/services/audioflinger/BufferProviders.cpp
new file mode 100644
index 0000000..e143805
--- /dev/null
+++ b/services/audioflinger/BufferProviders.cpp
@@ -0,0 +1,362 @@
+/*
+ * Copyright (C) 2015 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 "BufferProvider"
+//#define LOG_NDEBUG 0
+
+#include <audio_effects/effect_downmix.h>
+#include <audio_utils/primitives.h>
+#include <audio_utils/format.h>
+#include <media/EffectsFactoryApi.h>
+#include <utils/Log.h>
+
+#include "Configuration.h"
+#include "BufferProviders.h"
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
+#endif
+
+namespace android {
+
+// ----------------------------------------------------------------------------
+
+template <typename T>
+static inline T min(const T& a, const T& b)
+{
+    return a < b ? a : b;
+}
+
+CopyBufferProvider::CopyBufferProvider(size_t inputFrameSize,
+        size_t outputFrameSize, size_t bufferFrameCount) :
+        mInputFrameSize(inputFrameSize),
+        mOutputFrameSize(outputFrameSize),
+        mLocalBufferFrameCount(bufferFrameCount),
+        mLocalBufferData(NULL),
+        mConsumed(0)
+{
+    ALOGV("CopyBufferProvider(%p)(%zu, %zu, %zu)", this,
+            inputFrameSize, outputFrameSize, bufferFrameCount);
+    LOG_ALWAYS_FATAL_IF(inputFrameSize < outputFrameSize && bufferFrameCount == 0,
+            "Requires local buffer if inputFrameSize(%zu) < outputFrameSize(%zu)",
+            inputFrameSize, outputFrameSize);
+    if (mLocalBufferFrameCount) {
+        (void)posix_memalign(&mLocalBufferData, 32, mLocalBufferFrameCount * mOutputFrameSize);
+    }
+    mBuffer.frameCount = 0;
+}
+
+CopyBufferProvider::~CopyBufferProvider()
+{
+    ALOGV("~CopyBufferProvider(%p)", this);
+    if (mBuffer.frameCount != 0) {
+        mTrackBufferProvider->releaseBuffer(&mBuffer);
+    }
+    free(mLocalBufferData);
+}
+
+status_t CopyBufferProvider::getNextBuffer(AudioBufferProvider::Buffer *pBuffer,
+        int64_t pts)
+{
+    //ALOGV("CopyBufferProvider(%p)::getNextBuffer(%p (%zu), %lld)",
+    //        this, pBuffer, pBuffer->frameCount, pts);
+    if (mLocalBufferFrameCount == 0) {
+        status_t res = mTrackBufferProvider->getNextBuffer(pBuffer, pts);
+        if (res == OK) {
+            copyFrames(pBuffer->raw, pBuffer->raw, pBuffer->frameCount);
+        }
+        return res;
+    }
+    if (mBuffer.frameCount == 0) {
+        mBuffer.frameCount = pBuffer->frameCount;
+        status_t res = mTrackBufferProvider->getNextBuffer(&mBuffer, pts);
+        // At one time an upstream buffer provider had
+        // res == OK and mBuffer.frameCount == 0, doesn't seem to happen now 7/18/2014.
+        //
+        // By API spec, if res != OK, then mBuffer.frameCount == 0.
+        // but there may be improper implementations.
+        ALOG_ASSERT(res == OK || mBuffer.frameCount == 0);
+        if (res != OK || mBuffer.frameCount == 0) { // not needed by API spec, but to be safe.
+            pBuffer->raw = NULL;
+            pBuffer->frameCount = 0;
+            return res;
+        }
+        mConsumed = 0;
+    }
+    ALOG_ASSERT(mConsumed < mBuffer.frameCount);
+    size_t count = min(mLocalBufferFrameCount, mBuffer.frameCount - mConsumed);
+    count = min(count, pBuffer->frameCount);
+    pBuffer->raw = mLocalBufferData;
+    pBuffer->frameCount = count;
+    copyFrames(pBuffer->raw, (uint8_t*)mBuffer.raw + mConsumed * mInputFrameSize,
+            pBuffer->frameCount);
+    return OK;
+}
+
+void CopyBufferProvider::releaseBuffer(AudioBufferProvider::Buffer *pBuffer)
+{
+    //ALOGV("CopyBufferProvider(%p)::releaseBuffer(%p(%zu))",
+    //        this, pBuffer, pBuffer->frameCount);
+    if (mLocalBufferFrameCount == 0) {
+        mTrackBufferProvider->releaseBuffer(pBuffer);
+        return;
+    }
+    // LOG_ALWAYS_FATAL_IF(pBuffer->frameCount == 0, "Invalid framecount");
+    mConsumed += pBuffer->frameCount; // TODO: update for efficiency to reuse existing content
+    if (mConsumed != 0 && mConsumed >= mBuffer.frameCount) {
+        mTrackBufferProvider->releaseBuffer(&mBuffer);
+        ALOG_ASSERT(mBuffer.frameCount == 0);
+    }
+    pBuffer->raw = NULL;
+    pBuffer->frameCount = 0;
+}
+
+void CopyBufferProvider::reset()
+{
+    if (mBuffer.frameCount != 0) {
+        mTrackBufferProvider->releaseBuffer(&mBuffer);
+    }
+    mConsumed = 0;
+}
+
+DownmixerBufferProvider::DownmixerBufferProvider(
+        audio_channel_mask_t inputChannelMask,
+        audio_channel_mask_t outputChannelMask, audio_format_t format,
+        uint32_t sampleRate, int32_t sessionId, size_t bufferFrameCount) :
+        CopyBufferProvider(
+            audio_bytes_per_sample(format) * audio_channel_count_from_out_mask(inputChannelMask),
+            audio_bytes_per_sample(format) * audio_channel_count_from_out_mask(outputChannelMask),
+            bufferFrameCount)  // set bufferFrameCount to 0 to do in-place
+{
+    ALOGV("DownmixerBufferProvider(%p)(%#x, %#x, %#x %u %d)",
+            this, inputChannelMask, outputChannelMask, format,
+            sampleRate, sessionId);
+    if (!sIsMultichannelCapable
+            || EffectCreate(&sDwnmFxDesc.uuid,
+                    sessionId,
+                    SESSION_ID_INVALID_AND_IGNORED,
+                    &mDownmixHandle) != 0) {
+         ALOGE("DownmixerBufferProvider() error creating downmixer effect");
+         mDownmixHandle = NULL;
+         return;
+     }
+     // channel input configuration will be overridden per-track
+     mDownmixConfig.inputCfg.channels = inputChannelMask;   // FIXME: Should be bits
+     mDownmixConfig.outputCfg.channels = outputChannelMask; // FIXME: should be bits
+     mDownmixConfig.inputCfg.format = format;
+     mDownmixConfig.outputCfg.format = format;
+     mDownmixConfig.inputCfg.samplingRate = sampleRate;
+     mDownmixConfig.outputCfg.samplingRate = sampleRate;
+     mDownmixConfig.inputCfg.accessMode = EFFECT_BUFFER_ACCESS_READ;
+     mDownmixConfig.outputCfg.accessMode = EFFECT_BUFFER_ACCESS_WRITE;
+     // input and output buffer provider, and frame count will not be used as the downmix effect
+     // process() function is called directly (see DownmixerBufferProvider::getNextBuffer())
+     mDownmixConfig.inputCfg.mask = EFFECT_CONFIG_SMP_RATE | EFFECT_CONFIG_CHANNELS |
+             EFFECT_CONFIG_FORMAT | EFFECT_CONFIG_ACC_MODE;
+     mDownmixConfig.outputCfg.mask = mDownmixConfig.inputCfg.mask;
+
+     int cmdStatus;
+     uint32_t replySize = sizeof(int);
+
+     // Configure downmixer
+     status_t status = (*mDownmixHandle)->command(mDownmixHandle,
+             EFFECT_CMD_SET_CONFIG /*cmdCode*/, sizeof(effect_config_t) /*cmdSize*/,
+             &mDownmixConfig /*pCmdData*/,
+             &replySize, &cmdStatus /*pReplyData*/);
+     if (status != 0 || cmdStatus != 0) {
+         ALOGE("DownmixerBufferProvider() error %d cmdStatus %d while configuring downmixer",
+                 status, cmdStatus);
+         EffectRelease(mDownmixHandle);
+         mDownmixHandle = NULL;
+         return;
+     }
+
+     // Enable downmixer
+     replySize = sizeof(int);
+     status = (*mDownmixHandle)->command(mDownmixHandle,
+             EFFECT_CMD_ENABLE /*cmdCode*/, 0 /*cmdSize*/, NULL /*pCmdData*/,
+             &replySize, &cmdStatus /*pReplyData*/);
+     if (status != 0 || cmdStatus != 0) {
+         ALOGE("DownmixerBufferProvider() error %d cmdStatus %d while enabling downmixer",
+                 status, cmdStatus);
+         EffectRelease(mDownmixHandle);
+         mDownmixHandle = NULL;
+         return;
+     }
+
+     // Set downmix type
+     // parameter size rounded for padding on 32bit boundary
+     const int psizePadded = ((sizeof(downmix_params_t) - 1)/sizeof(int) + 1) * sizeof(int);
+     const int downmixParamSize =
+             sizeof(effect_param_t) + psizePadded + sizeof(downmix_type_t);
+     effect_param_t * const param = (effect_param_t *) malloc(downmixParamSize);
+     param->psize = sizeof(downmix_params_t);
+     const downmix_params_t downmixParam = DOWNMIX_PARAM_TYPE;
+     memcpy(param->data, &downmixParam, param->psize);
+     const downmix_type_t downmixType = DOWNMIX_TYPE_FOLD;
+     param->vsize = sizeof(downmix_type_t);
+     memcpy(param->data + psizePadded, &downmixType, param->vsize);
+     replySize = sizeof(int);
+     status = (*mDownmixHandle)->command(mDownmixHandle,
+             EFFECT_CMD_SET_PARAM /* cmdCode */, downmixParamSize /* cmdSize */,
+             param /*pCmdData*/, &replySize, &cmdStatus /*pReplyData*/);
+     free(param);
+     if (status != 0 || cmdStatus != 0) {
+         ALOGE("DownmixerBufferProvider() error %d cmdStatus %d while setting downmix type",
+                 status, cmdStatus);
+         EffectRelease(mDownmixHandle);
+         mDownmixHandle = NULL;
+         return;
+     }
+     ALOGV("DownmixerBufferProvider() downmix type set to %d", (int) downmixType);
+}
+
+DownmixerBufferProvider::~DownmixerBufferProvider()
+{
+    ALOGV("~DownmixerBufferProvider (%p)", this);
+    EffectRelease(mDownmixHandle);
+    mDownmixHandle = NULL;
+}
+
+void DownmixerBufferProvider::copyFrames(void *dst, const void *src, size_t frames)
+{
+    mDownmixConfig.inputCfg.buffer.frameCount = frames;
+    mDownmixConfig.inputCfg.buffer.raw = const_cast<void *>(src);
+    mDownmixConfig.outputCfg.buffer.frameCount = frames;
+    mDownmixConfig.outputCfg.buffer.raw = dst;
+    // may be in-place if src == dst.
+    status_t res = (*mDownmixHandle)->process(mDownmixHandle,
+            &mDownmixConfig.inputCfg.buffer, &mDownmixConfig.outputCfg.buffer);
+    ALOGE_IF(res != OK, "DownmixBufferProvider error %d", res);
+}
+
+/* call once in a pthread_once handler. */
+/*static*/ status_t DownmixerBufferProvider::init()
+{
+    // find multichannel downmix effect if we have to play multichannel content
+    uint32_t numEffects = 0;
+    int ret = EffectQueryNumberEffects(&numEffects);
+    if (ret != 0) {
+        ALOGE("AudioMixer() error %d querying number of effects", ret);
+        return NO_INIT;
+    }
+    ALOGV("EffectQueryNumberEffects() numEffects=%d", numEffects);
+
+    for (uint32_t i = 0 ; i < numEffects ; i++) {
+        if (EffectQueryEffect(i, &sDwnmFxDesc) == 0) {
+            ALOGV("effect %d is called %s", i, sDwnmFxDesc.name);
+            if (memcmp(&sDwnmFxDesc.type, EFFECT_UIID_DOWNMIX, sizeof(effect_uuid_t)) == 0) {
+                ALOGI("found effect \"%s\" from %s",
+                        sDwnmFxDesc.name, sDwnmFxDesc.implementor);
+                sIsMultichannelCapable = true;
+                break;
+            }
+        }
+    }
+    ALOGW_IF(!sIsMultichannelCapable, "unable to find downmix effect");
+    return NO_INIT;
+}
+
+/*static*/ bool DownmixerBufferProvider::sIsMultichannelCapable = false;
+/*static*/ effect_descriptor_t DownmixerBufferProvider::sDwnmFxDesc;
+
+RemixBufferProvider::RemixBufferProvider(audio_channel_mask_t inputChannelMask,
+        audio_channel_mask_t outputChannelMask, audio_format_t format,
+        size_t bufferFrameCount) :
+        CopyBufferProvider(
+                audio_bytes_per_sample(format)
+                    * audio_channel_count_from_out_mask(inputChannelMask),
+                audio_bytes_per_sample(format)
+                    * audio_channel_count_from_out_mask(outputChannelMask),
+                bufferFrameCount),
+        mFormat(format),
+        mSampleSize(audio_bytes_per_sample(format)),
+        mInputChannels(audio_channel_count_from_out_mask(inputChannelMask)),
+        mOutputChannels(audio_channel_count_from_out_mask(outputChannelMask))
+{
+    ALOGV("RemixBufferProvider(%p)(%#x, %#x, %#x) %zu %zu",
+            this, format, inputChannelMask, outputChannelMask,
+            mInputChannels, mOutputChannels);
+
+    const audio_channel_representation_t inputRepresentation =
+            audio_channel_mask_get_representation(inputChannelMask);
+    const audio_channel_representation_t outputRepresentation =
+            audio_channel_mask_get_representation(outputChannelMask);
+    const uint32_t inputBits = audio_channel_mask_get_bits(inputChannelMask);
+    const uint32_t outputBits = audio_channel_mask_get_bits(outputChannelMask);
+
+    switch (inputRepresentation) {
+    case AUDIO_CHANNEL_REPRESENTATION_POSITION:
+        switch (outputRepresentation) {
+        case AUDIO_CHANNEL_REPRESENTATION_POSITION:
+            memcpy_by_index_array_initialization(mIdxAry, ARRAY_SIZE(mIdxAry),
+                    outputBits, inputBits);
+            return;
+        case AUDIO_CHANNEL_REPRESENTATION_INDEX:
+            // TODO: output channel index mask not currently allowed
+            // fall through
+        default:
+            break;
+        }
+        break;
+    case AUDIO_CHANNEL_REPRESENTATION_INDEX:
+        switch (outputRepresentation) {
+        case AUDIO_CHANNEL_REPRESENTATION_POSITION:
+            memcpy_by_index_array_initialization_src_index(mIdxAry, ARRAY_SIZE(mIdxAry),
+                    outputBits, inputBits);
+            return;
+        case AUDIO_CHANNEL_REPRESENTATION_INDEX:
+            // TODO: output channel index mask not currently allowed
+            // fall through
+        default:
+            break;
+        }
+        break;
+    default:
+        break;
+    }
+    LOG_ALWAYS_FATAL("invalid channel mask conversion from %#x to %#x",
+            inputChannelMask, outputChannelMask);
+}
+
+void RemixBufferProvider::copyFrames(void *dst, const void *src, size_t frames)
+{
+    memcpy_by_index_array(dst, mOutputChannels,
+            src, mInputChannels, mIdxAry, mSampleSize, frames);
+}
+
+ReformatBufferProvider::ReformatBufferProvider(int32_t channelCount,
+        audio_format_t inputFormat, audio_format_t outputFormat,
+        size_t bufferFrameCount) :
+        CopyBufferProvider(
+                channelCount * audio_bytes_per_sample(inputFormat),
+                channelCount * audio_bytes_per_sample(outputFormat),
+                bufferFrameCount),
+        mChannelCount(channelCount),
+        mInputFormat(inputFormat),
+        mOutputFormat(outputFormat)
+{
+    ALOGV("ReformatBufferProvider(%p)(%u, %#x, %#x)",
+            this, channelCount, inputFormat, outputFormat);
+}
+
+void ReformatBufferProvider::copyFrames(void *dst, const void *src, size_t frames)
+{
+    memcpy_by_audio_format(dst, mOutputFormat, src, mInputFormat, frames * mChannelCount);
+}
+
+// ----------------------------------------------------------------------------
+} // namespace android
diff --git a/services/audioflinger/BufferProviders.h b/services/audioflinger/BufferProviders.h
new file mode 100644
index 0000000..7145b80
--- /dev/null
+++ b/services/audioflinger/BufferProviders.h
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2015 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 ANDROID_BUFFER_PROVIDERS_H
+#define ANDROID_BUFFER_PROVIDERS_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <hardware/audio_effect.h>
+#include <media/AudioBufferProvider.h>
+#include <system/audio.h>
+
+namespace android {
+
+// ----------------------------------------------------------------------------
+
+class PassthruBufferProvider : public AudioBufferProvider {
+public:
+    PassthruBufferProvider() : mTrackBufferProvider(NULL) { }
+
+    virtual ~PassthruBufferProvider() { }
+
+    // call this to release the buffer to the upstream provider.
+    // treat it as an audio discontinuity for future samples.
+    virtual void reset() { }
+
+    // set the upstream buffer provider. Consider calling "reset" before this function.
+    virtual void setBufferProvider(AudioBufferProvider *p) {
+        mTrackBufferProvider = p;
+    }
+
+protected:
+    AudioBufferProvider *mTrackBufferProvider;
+};
+
+// Base AudioBufferProvider class used for DownMixerBufferProvider, RemixBufferProvider,
+// and ReformatBufferProvider.
+// It handles a private buffer for use in converting format or channel masks from the
+// input data to a form acceptable by the mixer.
+// TODO: Make a ResamplerBufferProvider when integers are entirely removed from the
+// processing pipeline.
+class CopyBufferProvider : public PassthruBufferProvider {
+public:
+    // Use a private buffer of bufferFrameCount frames (each frame is outputFrameSize bytes).
+    // If bufferFrameCount is 0, no private buffer is created and in-place modification of
+    // the upstream buffer provider's buffers is performed by copyFrames().
+    CopyBufferProvider(size_t inputFrameSize, size_t outputFrameSize,
+            size_t bufferFrameCount);
+    virtual ~CopyBufferProvider();
+
+    // Overrides AudioBufferProvider methods
+    virtual status_t getNextBuffer(Buffer *buffer, int64_t pts);
+    virtual void releaseBuffer(Buffer *buffer);
+
+    // Overrides PassthruBufferProvider
+    virtual void reset();
+
+    // this function should be supplied by the derived class.  It converts
+    // #frames in the *src pointer to the *dst pointer.  It is public because
+    // some providers will allow this to work on arbitrary buffers outside
+    // of the internal buffers.
+    virtual void copyFrames(void *dst, const void *src, size_t frames) = 0;
+
+protected:
+    const size_t         mInputFrameSize;
+    const size_t         mOutputFrameSize;
+private:
+    AudioBufferProvider::Buffer mBuffer;
+    const size_t         mLocalBufferFrameCount;
+    void                *mLocalBufferData;
+    size_t               mConsumed;
+};
+
+// DownmixerBufferProvider derives from CopyBufferProvider to provide
+// position dependent downmixing by an Audio Effect.
+class DownmixerBufferProvider : public CopyBufferProvider {
+public:
+    DownmixerBufferProvider(audio_channel_mask_t inputChannelMask,
+            audio_channel_mask_t outputChannelMask, audio_format_t format,
+            uint32_t sampleRate, int32_t sessionId, size_t bufferFrameCount);
+    virtual ~DownmixerBufferProvider();
+    //Overrides
+    virtual void copyFrames(void *dst, const void *src, size_t frames);
+
+    bool isValid() const { return mDownmixHandle != NULL; }
+    static status_t init();
+    static bool isMultichannelCapable() { return sIsMultichannelCapable; }
+
+protected:
+    effect_handle_t    mDownmixHandle;
+    effect_config_t    mDownmixConfig;
+
+    // effect descriptor for the downmixer used by the mixer
+    static effect_descriptor_t sDwnmFxDesc;
+    // indicates whether a downmix effect has been found and is usable by this mixer
+    static bool                sIsMultichannelCapable;
+    // FIXME: should we allow effects outside of the framework?
+    // We need to here. A special ioId that must be <= -2 so it does not map to a session.
+    static const int32_t SESSION_ID_INVALID_AND_IGNORED = -2;
+};
+
+// RemixBufferProvider derives from CopyBufferProvider to perform an
+// upmix or downmix to the proper channel count and mask.
+class RemixBufferProvider : public CopyBufferProvider {
+public:
+    RemixBufferProvider(audio_channel_mask_t inputChannelMask,
+            audio_channel_mask_t outputChannelMask, audio_format_t format,
+            size_t bufferFrameCount);
+    //Overrides
+    virtual void copyFrames(void *dst, const void *src, size_t frames);
+
+protected:
+    const audio_format_t mFormat;
+    const size_t         mSampleSize;
+    const size_t         mInputChannels;
+    const size_t         mOutputChannels;
+    int8_t               mIdxAry[sizeof(uint32_t) * 8]; // 32 bits => channel indices
+};
+
+// ReformatBufferProvider derives from CopyBufferProvider to convert the input data
+// to an acceptable mixer input format type.
+class ReformatBufferProvider : public CopyBufferProvider {
+public:
+    ReformatBufferProvider(int32_t channelCount,
+            audio_format_t inputFormat, audio_format_t outputFormat,
+            size_t bufferFrameCount);
+    virtual void copyFrames(void *dst, const void *src, size_t frames);
+
+protected:
+    const uint32_t       mChannelCount;
+    const audio_format_t mInputFormat;
+    const audio_format_t mOutputFormat;
+};
+
+// ----------------------------------------------------------------------------
+} // namespace android
+
+#endif // ANDROID_BUFFER_PROVIDERS_H
diff --git a/services/audioflinger/tests/Android.mk b/services/audioflinger/tests/Android.mk
index 8604ef5..76997be 100644
--- a/services/audioflinger/tests/Android.mk
+++ b/services/audioflinger/tests/Android.mk
@@ -39,6 +39,7 @@
 LOCAL_SRC_FILES:= \
 	test-mixer.cpp \
 	../AudioMixer.cpp.arm \
+	../BufferProviders.cpp
 
 LOCAL_C_INCLUDES := \
 	$(call include-path-for, audio-effects) \