diff --git a/services/camera/libcameraservice/Android.mk b/services/camera/libcameraservice/Android.mk
index 3479553..83d9ccd 100644
--- a/services/camera/libcameraservice/Android.mk
+++ b/services/camera/libcameraservice/Android.mk
@@ -27,6 +27,7 @@
     camera2/ProFrameProcessor.cpp \
     camera2/ZslProcessor3.cpp \
     camera3/Camera3Stream.cpp \
+    camera3/Camera3IOStreamBase.cpp \
     camera3/Camera3InputStream.cpp \
     camera3/Camera3OutputStream.cpp \
     camera3/Camera3ZslStream.cpp \
diff --git a/services/camera/libcameraservice/camera3/Camera3IOStreamBase.cpp b/services/camera/libcameraservice/camera3/Camera3IOStreamBase.cpp
new file mode 100644
index 0000000..abc28fe
--- /dev/null
+++ b/services/camera/libcameraservice/camera3/Camera3IOStreamBase.cpp
@@ -0,0 +1,273 @@
+/*
+ * 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 "Camera3-IOStreamBase"
+#define ATRACE_TAG ATRACE_TAG_CAMERA
+//#define LOG_NDEBUG 0
+
+// This is needed for stdint.h to define INT64_MAX in C++
+#define __STDC_LIMIT_MACROS
+
+#include <utils/Log.h>
+#include <utils/Trace.h>
+#include "Camera3IOStreamBase.h"
+
+namespace android {
+
+namespace camera3 {
+
+Camera3IOStreamBase::Camera3IOStreamBase(int id, camera3_stream_type_t type,
+        uint32_t width, uint32_t height, size_t maxSize, int format) :
+        Camera3Stream(id, type,
+                width, height, maxSize, format),
+        mTotalBufferCount(0),
+        mDequeuedBufferCount(0),
+        mFrameCount(0),
+        mLastTimestamp(0) {
+
+    mCombinedFence = new Fence();
+
+    if (maxSize > 0 && format != HAL_PIXEL_FORMAT_BLOB) {
+        ALOGE("%s: Bad format for size-only stream: %d", __FUNCTION__,
+                format);
+        mState = STATE_ERROR;
+    }
+}
+
+Camera3IOStreamBase::~Camera3IOStreamBase() {
+    disconnectLocked();
+}
+
+bool Camera3IOStreamBase::hasOutstandingBuffersLocked() const {
+    nsecs_t signalTime = mCombinedFence->getSignalTime();
+    ALOGV("%s: Stream %d: Has %d outstanding buffers,"
+            " buffer signal time is %lld",
+            __FUNCTION__, mId, mDequeuedBufferCount, signalTime);
+    if (mDequeuedBufferCount > 0 || signalTime == INT64_MAX) {
+        return true;
+    }
+    return false;
+}
+
+status_t Camera3IOStreamBase::waitUntilIdle(nsecs_t timeout) {
+    status_t res;
+    {
+        Mutex::Autolock l(mLock);
+        while (mDequeuedBufferCount > 0) {
+            if (timeout != TIMEOUT_NEVER) {
+                nsecs_t startTime = systemTime();
+                res = mBufferReturnedSignal.waitRelative(mLock, timeout);
+                if (res == TIMED_OUT) {
+                    return res;
+                } else if (res != OK) {
+                    ALOGE("%s: Error waiting for outstanding buffers: %s (%d)",
+                            __FUNCTION__, strerror(-res), res);
+                    return res;
+                }
+                nsecs_t deltaTime = systemTime() - startTime;
+                if (timeout <= deltaTime) {
+                    timeout = 0;
+                } else {
+                    timeout -= deltaTime;
+                }
+            } else {
+                res = mBufferReturnedSignal.wait(mLock);
+                if (res != OK) {
+                    ALOGE("%s: Error waiting for outstanding buffers: %s (%d)",
+                            __FUNCTION__, strerror(-res), res);
+                    return res;
+                }
+            }
+        }
+    }
+
+    // No lock
+
+    unsigned int timeoutMs;
+    if (timeout == TIMEOUT_NEVER) {
+        timeoutMs = Fence::TIMEOUT_NEVER;
+    } else if (timeout == 0) {
+        timeoutMs = 0;
+    } else {
+        // Round up to wait at least 1 ms
+        timeoutMs = (timeout + 999999) / 1000000;
+    }
+
+    return mCombinedFence->wait(timeoutMs);
+}
+
+void Camera3IOStreamBase::dump(int fd, const Vector<String16> &args) const {
+    (void) args;
+    String8 lines;
+    lines.appendFormat("      State: %d\n", mState);
+    lines.appendFormat("      Dims: %d x %d, format 0x%x\n",
+            camera3_stream::width, camera3_stream::height,
+            camera3_stream::format);
+    lines.appendFormat("      Max size: %d\n", mMaxSize);
+    lines.appendFormat("      Usage: %d, max HAL buffers: %d\n",
+            camera3_stream::usage, camera3_stream::max_buffers);
+    lines.appendFormat("      Frames produced: %d, last timestamp: %lld ns\n",
+            mFrameCount, mLastTimestamp);
+    lines.appendFormat("      Total buffers: %d, currently dequeued: %d\n",
+            mTotalBufferCount, mDequeuedBufferCount);
+    write(fd, lines.string(), lines.size());
+}
+
+status_t Camera3IOStreamBase::configureQueueLocked() {
+    status_t res;
+
+    switch (mState) {
+        case STATE_IN_RECONFIG:
+            res = disconnectLocked();
+            if (res != OK) {
+                return res;
+            }
+            break;
+        case STATE_IN_CONFIG:
+            // OK
+            break;
+        default:
+            ALOGE("%s: Bad state: %d", __FUNCTION__, mState);
+            return INVALID_OPERATION;
+    }
+
+    return OK;
+}
+
+size_t Camera3IOStreamBase::getBufferCountLocked() {
+    return mTotalBufferCount;
+}
+
+status_t Camera3IOStreamBase::disconnectLocked() {
+    switch (mState) {
+        case STATE_IN_RECONFIG:
+        case STATE_CONFIGURED:
+            // OK
+            break;
+        default:
+            // No connection, nothing to do
+            return OK;
+    }
+
+    if (mDequeuedBufferCount > 0) {
+        ALOGE("%s: Can't disconnect with %d buffers still dequeued!",
+                __FUNCTION__, mDequeuedBufferCount);
+        return INVALID_OPERATION;
+    }
+
+   return OK;
+}
+
+void Camera3IOStreamBase::handoutBufferLocked(camera3_stream_buffer &buffer,
+                                              buffer_handle_t *handle,
+                                              int acquireFence,
+                                              int releaseFence,
+                                              camera3_buffer_status_t status) {
+    /**
+     * Note that all fences are now owned by HAL.
+     */
+
+    // Handing out a raw pointer to this object. Increment internal refcount.
+    incStrong(this);
+    buffer.stream = this;
+    buffer.buffer = handle;
+    buffer.acquire_fence = acquireFence;
+    buffer.release_fence = releaseFence;
+    buffer.status = status;
+
+    mDequeuedBufferCount++;
+}
+
+status_t Camera3IOStreamBase::getBufferPreconditionCheckLocked() const {
+    // Allow dequeue during IN_[RE]CONFIG for registration
+    if (mState != STATE_CONFIGURED &&
+            mState != STATE_IN_CONFIG && mState != STATE_IN_RECONFIG) {
+        ALOGE("%s: Stream %d: Can't get buffers in unconfigured state %d",
+                __FUNCTION__, mId, mState);
+        return INVALID_OPERATION;
+    }
+
+    // Only limit dequeue amount when fully configured
+    if (mState == STATE_CONFIGURED &&
+            mDequeuedBufferCount == camera3_stream::max_buffers) {
+        ALOGE("%s: Stream %d: Already dequeued maximum number of simultaneous"
+                " buffers (%d)", __FUNCTION__, mId,
+                camera3_stream::max_buffers);
+        return INVALID_OPERATION;
+    }
+
+    return OK;
+}
+
+status_t Camera3IOStreamBase::returnBufferPreconditionCheckLocked() const {
+    // Allow buffers to be returned in the error state, to allow for disconnect
+    // and in the in-config states for registration
+    if (mState == STATE_CONSTRUCTED) {
+        ALOGE("%s: Stream %d: Can't return buffers in unconfigured state %d",
+                __FUNCTION__, mId, mState);
+        return INVALID_OPERATION;
+    }
+    if (mDequeuedBufferCount == 0) {
+        ALOGE("%s: Stream %d: No buffers outstanding to return", __FUNCTION__,
+                mId);
+        return INVALID_OPERATION;
+    }
+
+    return OK;
+}
+
+status_t Camera3IOStreamBase::returnAnyBufferLocked(
+        const camera3_stream_buffer &buffer,
+        nsecs_t timestamp,
+        bool output) {
+    status_t res;
+
+    // returnBuffer may be called from a raw pointer, not a sp<>, and we'll be
+    // decrementing the internal refcount next. In case this is the last ref, we
+    // might get destructed on the decStrong(), so keep an sp around until the
+    // end of the call - otherwise have to sprinkle the decStrong on all exit
+    // points.
+    sp<Camera3IOStreamBase> keepAlive(this);
+    decStrong(this);
+
+    if ((res = returnBufferPreconditionCheckLocked()) != OK) {
+        return res;
+    }
+
+    sp<Fence> releaseFence;
+    res = returnBufferCheckedLocked(buffer, timestamp, output,
+                                    &releaseFence);
+    if (res != OK) {
+        return res;
+    }
+
+    mCombinedFence = Fence::merge(mName, mCombinedFence, releaseFence);
+
+    mDequeuedBufferCount--;
+    mBufferReturnedSignal.signal();
+
+    if (output) {
+        mLastTimestamp = timestamp;
+    }
+
+    return OK;
+}
+
+
+
+}; // namespace camera3
+
+}; // namespace android
diff --git a/services/camera/libcameraservice/camera3/Camera3IOStreamBase.h b/services/camera/libcameraservice/camera3/Camera3IOStreamBase.h
new file mode 100644
index 0000000..74c4484
--- /dev/null
+++ b/services/camera/libcameraservice/camera3/Camera3IOStreamBase.h
@@ -0,0 +1,102 @@
+/*
+ * 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 ANDROID_SERVERS_CAMERA3_IO_STREAM_BASE_H
+#define ANDROID_SERVERS_CAMERA3_IO_STREAM_BASE_H
+
+#include <utils/RefBase.h>
+#include <gui/Surface.h>
+
+#include "Camera3Stream.h"
+
+namespace android {
+
+namespace camera3 {
+
+/**
+ * A base class for managing a single stream of I/O data from the camera device.
+ */
+class Camera3IOStreamBase :
+        public Camera3Stream {
+  protected:
+    Camera3IOStreamBase(int id, camera3_stream_type_t type,
+            uint32_t width, uint32_t height, size_t maxSize, int format);
+
+  public:
+
+    virtual ~Camera3IOStreamBase();
+
+    /**
+     * Camera3Stream interface
+     */
+
+    virtual status_t waitUntilIdle(nsecs_t timeout);
+    virtual void     dump(int fd, const Vector<String16> &args) const;
+
+  protected:
+    size_t            mTotalBufferCount;
+    // sum of input and output buffers that are currently acquired by HAL
+    size_t            mDequeuedBufferCount;
+    Condition         mBufferReturnedSignal;
+    uint32_t          mFrameCount;
+    // Last received output buffer's timestamp
+    nsecs_t           mLastTimestamp;
+
+    // The merged release fence for all returned buffers
+    sp<Fence>         mCombinedFence;
+
+    status_t         returnAnyBufferLocked(
+            const camera3_stream_buffer &buffer,
+            nsecs_t timestamp,
+            bool output);
+
+    virtual status_t returnBufferCheckedLocked(
+            const camera3_stream_buffer &buffer,
+            nsecs_t timestamp,
+            bool output,
+            /*out*/
+            sp<Fence> *releaseFenceOut) = 0;
+
+    /**
+     * Internal Camera3Stream interface
+     */
+    virtual bool     hasOutstandingBuffersLocked() const;
+
+    virtual size_t   getBufferCountLocked();
+
+    status_t getBufferPreconditionCheckLocked() const;
+    status_t returnBufferPreconditionCheckLocked() const;
+
+    // State check only
+    virtual status_t configureQueueLocked();
+    // State checks only
+    virtual status_t disconnectLocked();
+
+    // Hand out the buffer to a native location,
+    //   incrementing the internal refcount and dequeued buffer count
+    void handoutBufferLocked(camera3_stream_buffer &buffer,
+                             buffer_handle_t *handle,
+                             int acquire_fence,
+                             int release_fence,
+                             camera3_buffer_status_t status);
+
+}; // class Camera3IOStreamBase
+
+} // namespace camera3
+
+} // namespace android
+
+#endif
diff --git a/services/camera/libcameraservice/camera3/Camera3InputStream.cpp b/services/camera/libcameraservice/camera3/Camera3InputStream.cpp
index c7dd12a..13e9c83 100644
--- a/services/camera/libcameraservice/camera3/Camera3InputStream.cpp
+++ b/services/camera/libcameraservice/camera3/Camera3InputStream.cpp
@@ -18,9 +18,6 @@
 #define ATRACE_TAG ATRACE_TAG_CAMERA
 //#define LOG_NDEBUG 0
 
-// This is needed for stdint.h to define INT64_MAX in C++
-#define __STDC_LIMIT_MACROS
-
 #include <utils/Log.h>
 #include <utils/Trace.h>
 #include "Camera3InputStream.h"
@@ -31,12 +28,8 @@
 
 Camera3InputStream::Camera3InputStream(int id,
         uint32_t width, uint32_t height, int format) :
-        Camera3Stream(id, CAMERA3_STREAM_INPUT, width, height, 0, format),
-        mTotalBufferCount(0),
-        mDequeuedBufferCount(0),
-        mFrameCount(0),
-        mLastTimestamp(0) {
-    mCombinedFence = new Fence();
+        Camera3IOStreamBase(id, CAMERA3_STREAM_INPUT, width, height,
+                            /*maxSize*/0, format) {
 
     if (format == HAL_PIXEL_FORMAT_BLOB) {
         ALOGE("%s: Bad format, BLOB not supported", __FUNCTION__);
@@ -61,21 +54,8 @@
         return INVALID_OPERATION;
     }
 
-    // Allow acquire during IN_[RE]CONFIG for registration
-    if (mState != STATE_CONFIGURED &&
-            mState != STATE_IN_CONFIG && mState != STATE_IN_RECONFIG) {
-        ALOGE("%s: Stream %d: Can't get buffers in unconfigured state %d",
-                __FUNCTION__, mId, mState);
-        return INVALID_OPERATION;
-    }
-
-    // Only limit acquire amount when fully configured
-    if (mState == STATE_CONFIGURED &&
-            mDequeuedBufferCount == camera3_stream::max_buffers) {
-        ALOGE("%s: Stream %d: Already acquired maximum number of simultaneous"
-                " buffers (%d)", __FUNCTION__, mId,
-                camera3_stream::max_buffers);
-        return INVALID_OPERATION;
+    if ((res = getBufferPreconditionCheckLocked()) != OK) {
+        return res;
     }
 
     ANativeWindowBuffer* anb;
@@ -95,52 +75,31 @@
     anb = bufferItem.mGraphicBuffer->getNativeBuffer();
     assert(anb != NULL);
     fenceFd = bufferItem.mFence->dup();
+
     /**
      * FenceFD now owned by HAL except in case of error,
      * in which case we reassign it to acquire_fence
      */
-
-    // Handing out a raw pointer to this object. Increment internal refcount.
-    incStrong(this);
-    buffer->stream = this;
-    buffer->buffer = &(anb->handle);
-    buffer->acquire_fence = fenceFd;
-    buffer->release_fence = -1;
-    buffer->status = CAMERA3_BUFFER_STATUS_OK;
-
-    mDequeuedBufferCount++;
-
+    handoutBufferLocked(*buffer, &(anb->handle), /*acquireFence*/fenceFd,
+                        /*releaseFence*/-1, CAMERA3_BUFFER_STATUS_OK);
     mBuffersInFlight.push_back(bufferItem);
 
     return OK;
 }
 
-status_t Camera3InputStream::returnInputBufferLocked(
-        const camera3_stream_buffer &buffer) {
-    ATRACE_CALL();
+status_t Camera3InputStream::returnBufferCheckedLocked(
+            const camera3_stream_buffer &buffer,
+            nsecs_t timestamp,
+            bool output,
+            /*out*/
+            sp<Fence> *releaseFenceOut) {
+
+    (void)timestamp;
+    (void)output;
+    ALOG_ASSERT(!output, "Expected output to be false");
+
     status_t res;
 
-    // returnBuffer may be called from a raw pointer, not a sp<>, and we'll be
-    // decrementing the internal refcount next. In case this is the last ref, we
-    // might get destructed on the decStrong(), so keep an sp around until the
-    // end of the call - otherwise have to sprinkle the decStrong on all exit
-    // points.
-    sp<Camera3InputStream> keepAlive(this);
-    decStrong(this);
-
-    // Allow buffers to be returned in the error state, to allow for disconnect
-    // and in the in-config states for registration
-    if (mState == STATE_CONSTRUCTED) {
-        ALOGE("%s: Stream %d: Can't return buffers in unconfigured state %d",
-                __FUNCTION__, mId, mState);
-        return INVALID_OPERATION;
-    }
-    if (mDequeuedBufferCount == 0) {
-        ALOGE("%s: Stream %d: No buffers outstanding to return", __FUNCTION__,
-                mId);
-        return INVALID_OPERATION;
-    }
-
     bool bufferFound = false;
     BufferItem bufferItem;
     {
@@ -192,91 +151,24 @@
         return res;
     }
 
-    mCombinedFence = Fence::merge(mName, mCombinedFence, releaseFence);
-
-    mBufferReturnedSignal.signal();
+    *releaseFenceOut = releaseFence;
 
     return OK;
-
 }
 
-bool Camera3InputStream::hasOutstandingBuffersLocked() const {
-    nsecs_t signalTime = mCombinedFence->getSignalTime();
-    ALOGV("%s: Stream %d: Has %d outstanding buffers,"
-            " buffer signal time is %lld",
-            __FUNCTION__, mId, mDequeuedBufferCount, signalTime);
-    if (mDequeuedBufferCount > 0 || signalTime == INT64_MAX) {
-        return true;
-    }
-    return false;
-}
+status_t Camera3InputStream::returnInputBufferLocked(
+        const camera3_stream_buffer &buffer) {
+    ATRACE_CALL();
 
-status_t Camera3InputStream::waitUntilIdle(nsecs_t timeout) {
-    status_t res;
-    {
-        Mutex::Autolock l(mLock);
-        while (mDequeuedBufferCount > 0) {
-            if (timeout != TIMEOUT_NEVER) {
-                nsecs_t startTime = systemTime();
-                res = mBufferReturnedSignal.waitRelative(mLock, timeout);
-                if (res == TIMED_OUT) {
-                    return res;
-                } else if (res != OK) {
-                    ALOGE("%s: Error waiting for outstanding buffers: %s (%d)",
-                            __FUNCTION__, strerror(-res), res);
-                    return res;
-                }
-                nsecs_t deltaTime = systemTime() - startTime;
-                if (timeout <= deltaTime) {
-                    timeout = 0;
-                } else {
-                    timeout -= deltaTime;
-                }
-            } else {
-                res = mBufferReturnedSignal.wait(mLock);
-                if (res != OK) {
-                    ALOGE("%s: Error waiting for outstanding buffers: %s (%d)",
-                            __FUNCTION__, strerror(-res), res);
-                    return res;
-                }
-            }
-        }
-    }
-
-    // No lock
-
-    unsigned int timeoutMs;
-    if (timeout == TIMEOUT_NEVER) {
-        timeoutMs = Fence::TIMEOUT_NEVER;
-    } else if (timeout == 0) {
-        timeoutMs = 0;
-    } else {
-        // Round up to wait at least 1 ms
-        timeoutMs = (timeout + 999999) / 1000000;
-    }
-
-    return mCombinedFence->wait(timeoutMs);
-}
-
-size_t Camera3InputStream::getBufferCountLocked() {
-    return mTotalBufferCount;
+    return returnAnyBufferLocked(buffer, /*timestamp*/0, /*output*/false);
 }
 
 status_t Camera3InputStream::disconnectLocked() {
-    switch (mState) {
-        case STATE_IN_RECONFIG:
-        case STATE_CONFIGURED:
-            // OK
-            break;
-        default:
-            // No connection, nothing to do
-            return OK;
-    }
 
-    if (mDequeuedBufferCount > 0) {
-        ALOGE("%s: Can't disconnect with %d buffers still acquired!",
-                __FUNCTION__, mDequeuedBufferCount);
-        return INVALID_OPERATION;
+    status_t res;
+
+    if ((res = Camera3IOStreamBase::disconnectLocked()) != OK) {
+        return res;
     }
 
     assert(mBuffersInFlight.size() == 0);
@@ -285,7 +177,8 @@
      *  no-op since we can't disconnect the producer from the consumer-side
      */
 
-    mState = (mState == STATE_IN_RECONFIG) ? STATE_IN_CONFIG : STATE_CONSTRUCTED;
+    mState = (mState == STATE_IN_RECONFIG) ? STATE_IN_CONFIG
+                                           : STATE_CONSTRUCTED;
     return OK;
 }
 
@@ -297,36 +190,16 @@
     (void) args;
     String8 lines;
     lines.appendFormat("    Stream[%d]: Input\n", mId);
-    lines.appendFormat("      State: %d\n", mState);
-    lines.appendFormat("      Dims: %d x %d, format 0x%x\n",
-            camera3_stream::width, camera3_stream::height,
-            camera3_stream::format);
-    lines.appendFormat("      Max size: %d\n", mMaxSize);
-    lines.appendFormat("      Usage: %d, max HAL buffers: %d\n",
-            camera3_stream::usage, camera3_stream::max_buffers);
-    lines.appendFormat("      Frames produced: %d, last timestamp: %lld ns\n",
-            mFrameCount, mLastTimestamp);
-    lines.appendFormat("      Total buffers: %d, currently acquired: %d\n",
-            mTotalBufferCount, mDequeuedBufferCount);
     write(fd, lines.string(), lines.size());
+
+    Camera3IOStreamBase::dump(fd, args);
 }
 
 status_t Camera3InputStream::configureQueueLocked() {
     status_t res;
 
-    switch (mState) {
-        case STATE_IN_RECONFIG:
-            res = disconnectLocked();
-            if (res != OK) {
-                return res;
-            }
-            break;
-        case STATE_IN_CONFIG:
-            // OK
-            break;
-        default:
-            ALOGE("%s: Bad state: %d", __FUNCTION__, mState);
-            return INVALID_OPERATION;
+    if ((res = Camera3IOStreamBase::configureQueueLocked()) != OK) {
+        return res;
     }
 
     assert(mMaxSize == 0);
diff --git a/services/camera/libcameraservice/camera3/Camera3InputStream.h b/services/camera/libcameraservice/camera3/Camera3InputStream.h
index fd9f464..8adda88 100644
--- a/services/camera/libcameraservice/camera3/Camera3InputStream.h
+++ b/services/camera/libcameraservice/camera3/Camera3InputStream.h
@@ -21,7 +21,7 @@
 #include <gui/Surface.h>
 #include <gui/BufferItemConsumer.h>
 
-#include "Camera3Stream.h"
+#include "Camera3IOStreamBase.h"
 
 namespace android {
 
@@ -34,7 +34,7 @@
  * buffers by feeding them into the HAL, as well as releasing the buffers back
  * the buffers once the HAL is done with them.
  */
-class Camera3InputStream : public Camera3Stream {
+class Camera3InputStream : public Camera3IOStreamBase {
   public:
     /**
      * Set up a stream for formats that have fixed size, such as RAW and YUV.
@@ -42,7 +42,6 @@
     Camera3InputStream(int id, uint32_t width, uint32_t height, int format);
     ~Camera3InputStream();
 
-    virtual status_t waitUntilIdle(nsecs_t timeout);
     virtual void     dump(int fd, const Vector<String16> &args) const;
 
     /**
@@ -58,14 +57,16 @@
 
     sp<BufferItemConsumer> mConsumer;
     Vector<BufferItem> mBuffersInFlight;
-    size_t            mTotalBufferCount;
-    size_t            mDequeuedBufferCount;
-    Condition         mBufferReturnedSignal;
-    uint32_t          mFrameCount;
-    nsecs_t           mLastTimestamp;
 
-    // The merged release fence for all returned buffers
-    sp<Fence>         mCombinedFence;
+    /**
+     * Camera3IOStreamBase
+     */
+    virtual status_t returnBufferCheckedLocked(
+            const camera3_stream_buffer &buffer,
+            nsecs_t timestamp,
+            bool output,
+            /*out*/
+            sp<Fence> *releaseFenceOut);
 
     /**
      * Camera3Stream interface
@@ -74,11 +75,9 @@
     virtual status_t getInputBufferLocked(camera3_stream_buffer *buffer);
     virtual status_t returnInputBufferLocked(
             const camera3_stream_buffer &buffer);
-    virtual bool     hasOutstandingBuffersLocked() const;
     virtual status_t disconnectLocked();
 
     virtual status_t configureQueueLocked();
-    virtual size_t   getBufferCountLocked();
 
 }; // class Camera3InputStream
 
diff --git a/services/camera/libcameraservice/camera3/Camera3OutputStream.cpp b/services/camera/libcameraservice/camera3/Camera3OutputStream.cpp
index 055913a..a2c97d4 100644
--- a/services/camera/libcameraservice/camera3/Camera3OutputStream.cpp
+++ b/services/camera/libcameraservice/camera3/Camera3OutputStream.cpp
@@ -18,9 +18,6 @@
 #define ATRACE_TAG ATRACE_TAG_CAMERA
 //#define LOG_NDEBUG 0
 
-// This is needed for stdint.h to define INT64_MAX in C++
-#define __STDC_LIMIT_MACROS
-
 #include <utils/Log.h>
 #include <utils/Trace.h>
 #include "Camera3OutputStream.h"
@@ -37,15 +34,11 @@
 Camera3OutputStream::Camera3OutputStream(int id,
         sp<ANativeWindow> consumer,
         uint32_t width, uint32_t height, int format) :
-        Camera3Stream(id, CAMERA3_STREAM_OUTPUT, width, height, 0, format),
+        Camera3IOStreamBase(id, CAMERA3_STREAM_OUTPUT, width, height,
+                            /*maxSize*/0, format),
         mConsumer(consumer),
-        mTransform(0),
-        mTotalBufferCount(0),
-        mDequeuedBufferCount(0),
-        mFrameCount(0),
-        mLastTimestamp(0) {
+        mTransform(0) {
 
-    mCombinedFence = new Fence();
     if (mConsumer == NULL) {
         ALOGE("%s: Consumer is NULL!", __FUNCTION__);
         mState = STATE_ERROR;
@@ -55,16 +48,10 @@
 Camera3OutputStream::Camera3OutputStream(int id,
         sp<ANativeWindow> consumer,
         uint32_t width, uint32_t height, size_t maxSize, int format) :
-        Camera3Stream(id, CAMERA3_STREAM_OUTPUT,
-                width, height, maxSize, format),
+        Camera3IOStreamBase(id, CAMERA3_STREAM_OUTPUT, width, height, maxSize,
+                            format),
         mConsumer(consumer),
-        mTransform(0),
-        mTotalBufferCount(0),
-        mDequeuedBufferCount(0),
-        mFrameCount(0),
-        mLastTimestamp(0) {
-
-    mCombinedFence = new Fence();
+        mTransform(0) {
 
     if (format != HAL_PIXEL_FORMAT_BLOB) {
         ALOGE("%s: Bad format for size-only stream: %d", __FUNCTION__,
@@ -78,6 +65,18 @@
     }
 }
 
+Camera3OutputStream::Camera3OutputStream(int id, camera3_stream_type_t type,
+                                         uint32_t width, uint32_t height,
+                                         int format) :
+        Camera3IOStreamBase(id, type, width, height,
+                            /*maxSize*/0,
+                            format),
+        mTransform(0) {
+
+    // Subclasses expected to initialize mConsumer themselves
+}
+
+
 Camera3OutputStream::~Camera3OutputStream() {
     disconnectLocked();
 }
@@ -86,21 +85,8 @@
     ATRACE_CALL();
     status_t res;
 
-    // Allow dequeue during IN_[RE]CONFIG for registration
-    if (mState != STATE_CONFIGURED &&
-            mState != STATE_IN_CONFIG && mState != STATE_IN_RECONFIG) {
-        ALOGE("%s: Stream %d: Can't get buffers in unconfigured state %d",
-                __FUNCTION__, mId, mState);
-        return INVALID_OPERATION;
-    }
-
-    // Only limit dequeue amount when fully configured
-    if (mState == STATE_CONFIGURED &&
-            mDequeuedBufferCount == camera3_stream::max_buffers) {
-        ALOGE("%s: Stream %d: Already dequeued maximum number of simultaneous"
-                " buffers (%d)", __FUNCTION__, mId,
-                camera3_stream::max_buffers);
-        return INVALID_OPERATION;
+    if ((res = getBufferPreconditionCheckLocked()) != OK) {
+        return res;
     }
 
     ANativeWindowBuffer* anb;
@@ -113,15 +99,12 @@
         return res;
     }
 
-    // Handing out a raw pointer to this object. Increment internal refcount.
-    incStrong(this);
-    buffer->stream = this;
-    buffer->buffer = &(anb->handle);
-    buffer->acquire_fence = fenceFd;
-    buffer->release_fence = -1;
-    buffer->status = CAMERA3_BUFFER_STATUS_OK;
-
-    mDequeuedBufferCount++;
+    /**
+     * FenceFD now owned by HAL except in case of error,
+     * in which case we reassign it to acquire_fence
+     */
+    handoutBufferLocked(*buffer, &(anb->handle), /*acquireFence*/fenceFd,
+                        /*releaseFence*/-1, CAMERA3_BUFFER_STATUS_OK);
 
     return OK;
 }
@@ -130,29 +113,29 @@
         const camera3_stream_buffer &buffer,
         nsecs_t timestamp) {
     ATRACE_CALL();
+
+    status_t res = returnAnyBufferLocked(buffer, timestamp, /*output*/true);
+
+    if (res != OK) {
+        return res;
+    }
+
+    mLastTimestamp = timestamp;
+
+    return OK;
+}
+
+status_t Camera3OutputStream::returnBufferCheckedLocked(
+            const camera3_stream_buffer &buffer,
+            nsecs_t timestamp,
+            bool output,
+            /*out*/
+            sp<Fence> *releaseFenceOut) {
+
+    (void)output;
+    ALOG_ASSERT(output, "Expected output to be true");
+
     status_t res;
-
-    // returnBuffer may be called from a raw pointer, not a sp<>, and we'll be
-    // decrementing the internal refcount next. In case this is the last ref, we
-    // might get destructed on the decStrong(), so keep an sp around until the
-    // end of the call - otherwise have to sprinkle the decStrong on all exit
-    // points.
-    sp<Camera3OutputStream> keepAlive(this);
-    decStrong(this);
-
-    // Allow buffers to be returned in the error state, to allow for disconnect
-    // and in the in-config states for registration
-    if (mState == STATE_CONSTRUCTED) {
-        ALOGE("%s: Stream %d: Can't return buffers in unconfigured state %d",
-                __FUNCTION__, mId, mState);
-        return INVALID_OPERATION;
-    }
-    if (mDequeuedBufferCount == 0) {
-        ALOGE("%s: Stream %d: No buffers outstanding to return", __FUNCTION__,
-                mId);
-        return INVALID_OPERATION;
-    }
-
     sp<Fence> releaseFence;
 
     /**
@@ -173,7 +156,7 @@
         res = native_window_set_buffers_timestamp(mConsumer.get(), timestamp);
         if (res != OK) {
             ALOGE("%s: Stream %d: Error setting timestamp: %s (%d)",
-                    __FUNCTION__, mId, strerror(-res), res);
+                  __FUNCTION__, mId, strerror(-res), res);
             return res;
         }
 
@@ -192,15 +175,15 @@
                 anwReleaseFence);
         if (res != OK) {
             ALOGE("%s: Stream %d: Error cancelling buffer to native window:"
-                    " %s (%d)", __FUNCTION__, mId, strerror(-res), res);
+                  " %s (%d)", __FUNCTION__, mId, strerror(-res), res);
         }
     } else {
         res = mConsumer->queueBuffer(mConsumer.get(),
                 container_of(buffer.buffer, ANativeWindowBuffer, handle),
                 anwReleaseFence);
         if (res != OK) {
-            ALOGE("%s: Stream %d: Error queueing buffer to native window: %s (%d)",
-                    __FUNCTION__, mId, strerror(-res), res);
+            ALOGE("%s: Stream %d: Error queueing buffer to native window: "
+                  "%s (%d)", __FUNCTION__, mId, strerror(-res), res);
         }
     }
 
@@ -209,89 +192,18 @@
         return res;
     }
 
-    mCombinedFence = Fence::merge(mName, mCombinedFence, releaseFence);
-
-    mDequeuedBufferCount--;
-    mBufferReturnedSignal.signal();
-    mLastTimestamp = timestamp;
+    *releaseFenceOut = releaseFence;
 
     return OK;
 }
 
-bool Camera3OutputStream::hasOutstandingBuffersLocked() const {
-    nsecs_t signalTime = mCombinedFence->getSignalTime();
-    ALOGV("%s: Stream %d: Has %d outstanding buffers,"
-            " buffer signal time is %lld",
-            __FUNCTION__, mId, mDequeuedBufferCount, signalTime);
-    if (mDequeuedBufferCount > 0 || signalTime == INT64_MAX) {
-        return true;
-    }
-    return false;
-}
-
-status_t Camera3OutputStream::waitUntilIdle(nsecs_t timeout) {
-    status_t res;
-    {
-        Mutex::Autolock l(mLock);
-        while (mDequeuedBufferCount > 0) {
-            if (timeout != TIMEOUT_NEVER) {
-                nsecs_t startTime = systemTime();
-                res = mBufferReturnedSignal.waitRelative(mLock, timeout);
-                if (res == TIMED_OUT) {
-                    return res;
-                } else if (res != OK) {
-                    ALOGE("%s: Error waiting for outstanding buffers: %s (%d)",
-                            __FUNCTION__, strerror(-res), res);
-                    return res;
-                }
-                nsecs_t deltaTime = systemTime() - startTime;
-                if (timeout <= deltaTime) {
-                    timeout = 0;
-                } else {
-                    timeout -= deltaTime;
-                }
-            } else {
-                res = mBufferReturnedSignal.wait(mLock);
-                if (res != OK) {
-                    ALOGE("%s: Error waiting for outstanding buffers: %s (%d)",
-                            __FUNCTION__, strerror(-res), res);
-                    return res;
-                }
-            }
-        }
-    }
-
-    // No lock
-
-    unsigned int timeoutMs;
-    if (timeout == TIMEOUT_NEVER) {
-        timeoutMs = Fence::TIMEOUT_NEVER;
-    } else if (timeout == 0) {
-        timeoutMs = 0;
-    } else {
-        // Round up to wait at least 1 ms
-        timeoutMs = (timeout + 999999) / 1000000;
-    }
-
-    return mCombinedFence->wait(timeoutMs);
-}
-
 void Camera3OutputStream::dump(int fd, const Vector<String16> &args) const {
     (void) args;
     String8 lines;
     lines.appendFormat("    Stream[%d]: Output\n", mId);
-    lines.appendFormat("      State: %d\n", mState);
-    lines.appendFormat("      Dims: %d x %d, format 0x%x\n",
-            camera3_stream::width, camera3_stream::height,
-            camera3_stream::format);
-    lines.appendFormat("      Max size: %d\n", mMaxSize);
-    lines.appendFormat("      Usage: %d, max HAL buffers: %d\n",
-            camera3_stream::usage, camera3_stream::max_buffers);
-    lines.appendFormat("      Frames produced: %d, last timestamp: %lld ns\n",
-            mFrameCount, mLastTimestamp);
-    lines.appendFormat("      Total buffers: %d, currently dequeued: %d\n",
-            mTotalBufferCount, mDequeuedBufferCount);
     write(fd, lines.string(), lines.size());
+
+    Camera3IOStreamBase::dump(fd, args);
 }
 
 status_t Camera3OutputStream::setTransform(int transform) {
@@ -322,21 +234,12 @@
 status_t Camera3OutputStream::configureQueueLocked() {
     status_t res;
 
-    switch (mState) {
-        case STATE_IN_RECONFIG:
-            res = disconnectLocked();
-            if (res != OK) {
-                return res;
-            }
-            break;
-        case STATE_IN_CONFIG:
-            // OK
-            break;
-        default:
-            ALOGE("%s: Bad state: %d", __FUNCTION__, mState);
-            return INVALID_OPERATION;
+    if ((res = Camera3IOStreamBase::configureQueueLocked()) != OK) {
+        return res;
     }
 
+    ALOG_ASSERT(mConsumer != 0, "mConsumer should never be NULL");
+
     // Configure consumer-side ANativeWindow interface
     res = native_window_api_connect(mConsumer.get(),
             NATIVE_WINDOW_API_CAMERA);
@@ -415,30 +318,15 @@
     return OK;
 }
 
-size_t Camera3OutputStream::getBufferCountLocked() {
-    return mTotalBufferCount;
-}
-
 status_t Camera3OutputStream::disconnectLocked() {
     status_t res;
 
-    switch (mState) {
-        case STATE_IN_RECONFIG:
-        case STATE_CONFIGURED:
-            // OK
-            break;
-        default:
-            // No connection, nothing to do
-            return OK;
+    if ((res = Camera3IOStreamBase::disconnectLocked()) != OK) {
+        return res;
     }
 
-    if (mDequeuedBufferCount > 0) {
-        ALOGE("%s: Can't disconnect with %d buffers still dequeued!",
-                __FUNCTION__, mDequeuedBufferCount);
-        return INVALID_OPERATION;
-    }
-
-    res = native_window_api_disconnect(mConsumer.get(), NATIVE_WINDOW_API_CAMERA);
+    res = native_window_api_disconnect(mConsumer.get(),
+                                       NATIVE_WINDOW_API_CAMERA);
 
     /**
      * This is not an error. if client calling process dies, the window will
@@ -450,13 +338,15 @@
                 " native window died from under us", __FUNCTION__, mId);
     }
     else if (res != OK) {
-        ALOGE("%s: Unable to disconnect stream %d from native window (error %d %s)",
-                __FUNCTION__, mId, res, strerror(-res));
+        ALOGE("%s: Unable to disconnect stream %d from native window "
+              "(error %d %s)",
+              __FUNCTION__, mId, res, strerror(-res));
         mState = STATE_ERROR;
         return res;
     }
 
-    mState = (mState == STATE_IN_RECONFIG) ? STATE_IN_CONFIG : STATE_CONSTRUCTED;
+    mState = (mState == STATE_IN_RECONFIG) ? STATE_IN_CONFIG
+                                           : STATE_CONSTRUCTED;
     return OK;
 }
 
diff --git a/services/camera/libcameraservice/camera3/Camera3OutputStream.h b/services/camera/libcameraservice/camera3/Camera3OutputStream.h
index 2464dce..ce317f9 100644
--- a/services/camera/libcameraservice/camera3/Camera3OutputStream.h
+++ b/services/camera/libcameraservice/camera3/Camera3OutputStream.h
@@ -21,6 +21,7 @@
 #include <gui/Surface.h>
 
 #include "Camera3Stream.h"
+#include "Camera3IOStreamBase.h"
 #include "Camera3OutputStreamInterface.h"
 
 namespace android {
@@ -31,7 +32,7 @@
  * A class for managing a single stream of output data from the camera device.
  */
 class Camera3OutputStream :
-        public Camera3Stream,
+        public Camera3IOStreamBase,
         public Camera3OutputStreamInterface {
   public:
     /**
@@ -53,7 +54,6 @@
      * Camera3Stream interface
      */
 
-    virtual status_t waitUntilIdle(nsecs_t timeout);
     virtual void     dump(int fd, const Vector<String16> &args) const;
 
     /**
@@ -62,19 +62,22 @@
      */
     status_t         setTransform(int transform);
 
-  private:
+  protected:
+    Camera3OutputStream(int id, camera3_stream_type_t type,
+            uint32_t width, uint32_t height, int format);
+
+    virtual status_t returnBufferCheckedLocked(
+            const camera3_stream_buffer &buffer,
+            nsecs_t timestamp,
+            bool output,
+            /*out*/
+            sp<Fence> *releaseFenceOut);
+
     sp<ANativeWindow> mConsumer;
+  private:
     int               mTransform;
-    size_t            mTotalBufferCount;
-    size_t            mDequeuedBufferCount;
-    Condition         mBufferReturnedSignal;
-    uint32_t          mFrameCount;
-    nsecs_t           mLastTimestamp;
 
-    // The merged release fence for all returned buffers
-    sp<Fence>         mCombinedFence;
-
-    status_t         setTransformLocked(int transform);
+    virtual status_t  setTransformLocked(int transform);
 
     /**
      * Internal Camera3Stream interface
@@ -83,12 +86,9 @@
     virtual status_t returnBufferLocked(
             const camera3_stream_buffer &buffer,
             nsecs_t timestamp);
-    virtual bool     hasOutstandingBuffersLocked() const;
 
     virtual status_t configureQueueLocked();
-    virtual size_t   getBufferCountLocked();
     virtual status_t disconnectLocked();
-
 }; // class Camera3OutputStream
 
 } // namespace camera3
diff --git a/services/camera/libcameraservice/camera3/Camera3ZslStream.cpp b/services/camera/libcameraservice/camera3/Camera3ZslStream.cpp
index 5a13dde..8790c8c 100644
--- a/services/camera/libcameraservice/camera3/Camera3ZslStream.cpp
+++ b/services/camera/libcameraservice/camera3/Camera3ZslStream.cpp
@@ -18,18 +18,10 @@
 #define ATRACE_TAG ATRACE_TAG_CAMERA
 //#define LOG_NDEBUG 0
 
-// This is needed for stdint.h to define INT64_MAX in C++
-#define __STDC_LIMIT_MACROS
-
 #include <utils/Log.h>
 #include <utils/Trace.h>
 #include "Camera3ZslStream.h"
 
-#ifndef container_of
-#define container_of(ptr, type, member) \
-    (type *)((char*)(ptr) - offsetof(type, member))
-#endif
-
 typedef android::RingBufferConsumer::PinnedBufferItem PinnedBufferItem;
 
 namespace android {
@@ -118,358 +110,24 @@
 
 Camera3ZslStream::Camera3ZslStream(int id, uint32_t width, uint32_t height,
         int depth) :
-        Camera3Stream(id, CAMERA3_STREAM_BIDIRECTIONAL, width, height, 0,
-                HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED),
+        Camera3OutputStream(id, CAMERA3_STREAM_BIDIRECTIONAL,
+                            width, height,
+                            HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED),
         mDepth(depth),
         mProducer(new RingBufferConsumer(GRALLOC_USAGE_HW_CAMERA_ZSL,
-                                         depth)),
-        mConsumer(new Surface(mProducer->getProducerInterface())),
-        //mTransform(0),
-        mTotalBufferCount(0),
-        mDequeuedBufferCount(0),
-        mFrameCount(0),
-        mLastTimestamp(0),
-        mCombinedFence(new Fence()) {
+                                         depth)) {
+
+        mConsumer = new Surface(mProducer->getProducerInterface());
 }
 
 Camera3ZslStream::~Camera3ZslStream() {
-    disconnectLocked();
-}
-
-status_t Camera3ZslStream::getBufferLocked(camera3_stream_buffer *buffer) {
-    // same as output stream code
-    ATRACE_CALL();
-    status_t res;
-
-    // Allow dequeue during IN_[RE]CONFIG for registration
-    if (mState != STATE_CONFIGURED &&
-            mState != STATE_IN_CONFIG && mState != STATE_IN_RECONFIG) {
-        ALOGE("%s: Stream %d: Can't get buffers in unconfigured state %d",
-                __FUNCTION__, mId, mState);
-        return INVALID_OPERATION;
-    }
-
-    // Only limit dequeue amount when fully configured
-    if (mState == STATE_CONFIGURED &&
-            mDequeuedBufferCount == camera3_stream::max_buffers) {
-        ALOGE("%s: Stream %d: Already dequeued maximum number of simultaneous"
-                " buffers (%d)", __FUNCTION__, mId,
-                camera3_stream::max_buffers);
-        return INVALID_OPERATION;
-    }
-
-    ANativeWindowBuffer* anb;
-    int fenceFd;
-
-    res = mConsumer->dequeueBuffer(mConsumer.get(), &anb, &fenceFd);
-    if (res != OK) {
-        ALOGE("%s: Stream %d: Can't dequeue next output buffer: %s (%d)",
-                __FUNCTION__, mId, strerror(-res), res);
-        return res;
-    }
-
-    // Handing out a raw pointer to this object. Increment internal refcount.
-    incStrong(this);
-    buffer->stream = this;
-    buffer->buffer = &(anb->handle);
-    buffer->acquire_fence = fenceFd;
-    buffer->release_fence = -1;
-    buffer->status = CAMERA3_BUFFER_STATUS_OK;
-
-    mDequeuedBufferCount++;
-
-    return OK;
-}
-
-status_t Camera3ZslStream::returnBufferLocked(
-        const camera3_stream_buffer &buffer,
-        nsecs_t timestamp) {
-    // same as output stream code
-    ATRACE_CALL();
-    status_t res;
-
-    // returnBuffer may be called from a raw pointer, not a sp<>, and we'll be
-    // decrementing the internal refcount next. In case this is the last ref, we
-    // might get destructed on the decStrong(), so keep an sp around until the
-    // end of the call - otherwise have to sprinkle the decStrong on all exit
-    // points.
-    sp<Camera3ZslStream> keepAlive(this);
-    decStrong(this);
-
-    // Allow buffers to be returned in the error state, to allow for disconnect
-    // and in the in-config states for registration
-    if (mState == STATE_CONSTRUCTED) {
-        ALOGE("%s: Stream %d: Can't return buffers in unconfigured state %d",
-                __FUNCTION__, mId, mState);
-        return INVALID_OPERATION;
-    }
-    if (mDequeuedBufferCount == 0) {
-        ALOGE("%s: Stream %d: No buffers outstanding to return", __FUNCTION__,
-                mId);
-        return INVALID_OPERATION;
-    }
-
-    sp<Fence> releaseFence;
-
-    /**
-     * Fence management - calculate Release Fence
-     */
-    if (buffer.status == CAMERA3_BUFFER_STATUS_ERROR) {
-        if (buffer.release_fence != -1) {
-            ALOGE("%s: Stream %d: HAL should not set release_fence(%d) when "
-                  "there is an error", __FUNCTION__, mId, buffer.release_fence);
-            close(buffer.release_fence);
-        }
-
-        /**
-         * Reassign release fence as the acquire fence in case of error
-         */
-        releaseFence = new Fence(buffer.acquire_fence);
-    } else {
-        res = native_window_set_buffers_timestamp(mConsumer.get(), timestamp);
-        if (res != OK) {
-            ALOGE("%s: Stream %d: Error setting timestamp: %s (%d)",
-                    __FUNCTION__, mId, strerror(-res), res);
-            return res;
-        }
-
-        releaseFence = new Fence(buffer.release_fence);
-    }
-
-    int anwReleaseFence = releaseFence->dup();
-
-    /**
-     * Return buffer back to ANativeWindow
-     */
-    if (buffer.status == CAMERA3_BUFFER_STATUS_ERROR) {
-        // Cancel buffer
-        res = mConsumer->cancelBuffer(mConsumer.get(),
-                container_of(buffer.buffer, ANativeWindowBuffer, handle),
-                anwReleaseFence);
-        if (res != OK) {
-            ALOGE("%s: Stream %d: Error cancelling buffer to native window:"
-                    " %s (%d)", __FUNCTION__, mId, strerror(-res), res);
-        }
-    } else {
-        res = mConsumer->queueBuffer(mConsumer.get(),
-                container_of(buffer.buffer, ANativeWindowBuffer, handle),
-                anwReleaseFence);
-        if (res != OK) {
-            ALOGE("%s: Stream %d: Error queueing buffer to native window: %s (%d)",
-                    __FUNCTION__, mId, strerror(-res), res);
-        }
-    }
-
-    if (res != OK) {
-        close(anwReleaseFence);
-        return res;
-    }
-    mCombinedFence = Fence::merge(mName, mCombinedFence, releaseFence);
-
-    mDequeuedBufferCount--;
-    mBufferReturnedSignal.signal();
-    mLastTimestamp = timestamp;
-
-    return OK;
-}
-
-bool Camera3ZslStream::hasOutstandingBuffersLocked() const {
-    // same as output stream
-    nsecs_t signalTime = mCombinedFence->getSignalTime();
-    ALOGV("%s: Stream %d: Has %d outstanding buffers,"
-            " buffer signal time is %lld",
-            __FUNCTION__, mId, mDequeuedBufferCount, signalTime);
-    if (mDequeuedBufferCount > 0 || signalTime == INT64_MAX) {
-        return true;
-    }
-    return false;
-}
-
-status_t Camera3ZslStream::waitUntilIdle(nsecs_t timeout) {
-    // same as output stream
-    status_t res;
-    {
-        Mutex::Autolock l(mLock);
-        while (mDequeuedBufferCount > 0) {
-            if (timeout != TIMEOUT_NEVER) {
-                nsecs_t startTime = systemTime();
-                res = mBufferReturnedSignal.waitRelative(mLock, timeout);
-                if (res == TIMED_OUT) {
-                    return res;
-                } else if (res != OK) {
-                    ALOGE("%s: Error waiting for outstanding buffers: %s (%d)",
-                            __FUNCTION__, strerror(-res), res);
-                    return res;
-                }
-                nsecs_t deltaTime = systemTime() - startTime;
-                if (timeout <= deltaTime) {
-                    timeout = 0;
-                } else {
-                    timeout -= deltaTime;
-                }
-            } else {
-                res = mBufferReturnedSignal.wait(mLock);
-                if (res != OK) {
-                    ALOGE("%s: Error waiting for outstanding buffers: %s (%d)",
-                            __FUNCTION__, strerror(-res), res);
-                    return res;
-                }
-            }
-        }
-    }
-
-    // No lock
-
-    unsigned int timeoutMs;
-    if (timeout == TIMEOUT_NEVER) {
-        timeoutMs = Fence::TIMEOUT_NEVER;
-    } else if (timeout == 0) {
-        timeoutMs = 0;
-    } else {
-        // Round up to wait at least 1 ms
-        timeoutMs = (timeout + 999999) / 1000000;
-    }
-
-    return mCombinedFence->wait(timeoutMs);
-}
-
-status_t Camera3ZslStream::configureQueueLocked() {
-    status_t res;
-
-    switch (mState) {
-        case STATE_IN_RECONFIG:
-            res = disconnectLocked();
-            if (res != OK) {
-                return res;
-            }
-            break;
-        case STATE_IN_CONFIG:
-            // OK
-            break;
-        default:
-            ALOGE("%s: Bad state: %d", __FUNCTION__, mState);
-            return INVALID_OPERATION;
-    }
-
-    // Configure consumer-side ANativeWindow interface
-    res = native_window_api_connect(mConsumer.get(),
-            NATIVE_WINDOW_API_CAMERA);
-    if (res != OK) {
-        ALOGE("%s: Unable to connect to native window for stream %d",
-                __FUNCTION__, mId);
-        return res;
-    }
-
-    res = native_window_set_usage(mConsumer.get(), camera3_stream::usage);
-    if (res != OK) {
-        ALOGE("%s: Unable to configure usage %08x for stream %d",
-                __FUNCTION__, camera3_stream::usage, mId);
-        return res;
-    }
-
-    res = native_window_set_scaling_mode(mConsumer.get(),
-            NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW);
-    if (res != OK) {
-        ALOGE("%s: Unable to configure stream scaling: %s (%d)",
-                __FUNCTION__, strerror(-res), res);
-        return res;
-    }
-
-    if (mMaxSize == 0) {
-        // For buffers of known size
-        res = native_window_set_buffers_geometry(mConsumer.get(),
-                camera3_stream::width, camera3_stream::height,
-                camera3_stream::format);
-    } else {
-        // For buffers with bounded size
-        res = native_window_set_buffers_geometry(mConsumer.get(),
-                mMaxSize, 1,
-                camera3_stream::format);
-    }
-    if (res != OK) {
-        ALOGE("%s: Unable to configure stream buffer geometry"
-                " %d x %d, format %x for stream %d",
-                __FUNCTION__, camera3_stream::width, camera3_stream::height,
-                camera3_stream::format, mId);
-        return res;
-    }
-
-    int maxConsumerBuffers;
-    res = mConsumer->query(mConsumer.get(),
-            NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS, &maxConsumerBuffers);
-    if (res != OK) {
-        ALOGE("%s: Unable to query consumer undequeued"
-                " buffer count for stream %d", __FUNCTION__, mId);
-        return res;
-    }
-
-    ALOGV("%s: Consumer wants %d buffers", __FUNCTION__,
-            maxConsumerBuffers);
-
-    mTotalBufferCount = maxConsumerBuffers + camera3_stream::max_buffers;
-    mDequeuedBufferCount = 0;
-    mFrameCount = 0;
-    mLastTimestamp = 0;
-
-    res = native_window_set_buffer_count(mConsumer.get(),
-            mTotalBufferCount);
-    if (res != OK) {
-        ALOGE("%s: Unable to set buffer count for stream %d",
-                __FUNCTION__, mId);
-        return res;
-    }
-
-    return OK;
-}
-
-size_t Camera3ZslStream::getBufferCountLocked() {
-    return mTotalBufferCount;
-}
-
-status_t Camera3ZslStream::disconnectLocked() {
-    status_t res;
-
-    switch (mState) {
-        case STATE_IN_RECONFIG:
-        case STATE_CONFIGURED:
-            // OK
-            break;
-        default:
-            // No connection, nothing to do
-            return OK;
-    }
-
-    if (mDequeuedBufferCount > 0) {
-        ALOGE("%s: Can't disconnect with %d buffers still dequeued!",
-                __FUNCTION__, mDequeuedBufferCount);
-        return INVALID_OPERATION;
-    }
-
-    res = native_window_api_disconnect(mConsumer.get(), NATIVE_WINDOW_API_CAMERA);
-
-    /**
-     * This is not an error. if client calling process dies, the window will
-     * also die and all calls to it will return DEAD_OBJECT, thus it's already
-     * "disconnected"
-     */
-    if (res == DEAD_OBJECT) {
-        ALOGW("%s: While disconnecting stream %d from native window, the"
-                " native window died from under us", __FUNCTION__, mId);
-    }
-    else if (res != OK) {
-        ALOGE("%s: Unable to disconnect stream %d from native window (error %d %s)",
-                __FUNCTION__, mId, res, strerror(-res));
-        mState = STATE_ERROR;
-        return res;
-    }
-
-    mState = (mState == STATE_IN_RECONFIG) ? STATE_IN_CONFIG : STATE_CONSTRUCTED;
-    return OK;
 }
 
 status_t Camera3ZslStream::getInputBufferLocked(camera3_stream_buffer *buffer) {
     ATRACE_CALL();
 
+    status_t res;
+
     // TODO: potentially register from inputBufferLocked
     // this should be ok, registerBuffersLocked only calls getBuffer for now
     // register in output mode instead of input mode for ZSL streams.
@@ -480,21 +138,8 @@
         return INVALID_OPERATION;
     }
 
-    // Allow dequeue during IN_[RE]CONFIG for registration
-    if (mState != STATE_CONFIGURED &&
-            mState != STATE_IN_CONFIG && mState != STATE_IN_RECONFIG) {
-        ALOGE("%s: Stream %d: Can't get buffers in unconfigured state %d",
-                __FUNCTION__, mId, mState);
-        return INVALID_OPERATION;
-    }
-
-    // Only limit dequeue amount when fully configured
-    if (mState == STATE_CONFIGURED &&
-            mDequeuedBufferCount == camera3_stream::max_buffers) {
-        ALOGE("%s: Stream %d: Already dequeued maximum number of simultaneous"
-                " buffers (%d)", __FUNCTION__, mId,
-                camera3_stream::max_buffers);
-        return INVALID_OPERATION;
+    if ((res = getBufferPreconditionCheckLocked()) != OK) {
+        return res;
     }
 
     ANativeWindowBuffer* anb;
@@ -526,47 +171,32 @@
      * FenceFD now owned by HAL except in case of error,
      * in which case we reassign it to acquire_fence
      */
-
-    // Handing out a raw pointer to this object. Increment internal refcount.
-    incStrong(this);
-    buffer->stream = this;
-    buffer->buffer = &(anb->handle);
-    buffer->acquire_fence = fenceFd;
-    buffer->release_fence = -1;
-    buffer->status = CAMERA3_BUFFER_STATUS_OK;
-
-    mDequeuedBufferCount++;
+    handoutBufferLocked(*buffer, &(anb->handle), /*acquireFence*/fenceFd,
+                         /*releaseFence*/-1, CAMERA3_BUFFER_STATUS_OK);
 
     mBuffersInFlight.push_back(bufferItem);
 
     return OK;
 }
 
-status_t Camera3ZslStream::returnInputBufferLocked(
-        const camera3_stream_buffer &buffer) {
-    ATRACE_CALL();
+status_t Camera3ZslStream::returnBufferCheckedLocked(
+            const camera3_stream_buffer &buffer,
+            nsecs_t timestamp,
+            bool output,
+            /*out*/
+            sp<Fence> *releaseFenceOut) {
 
-    // returnBuffer may be called from a raw pointer, not a sp<>, and we'll be
-    // decrementing the internal refcount next. In case this is the last ref, we
-    // might get destructed on the decStrong(), so keep an sp around until the
-    // end of the call - otherwise have to sprinkle the decStrong on all exit
-    // points.
-    sp<Camera3ZslStream> keepAlive(this);
-    decStrong(this);
-
-    // Allow buffers to be returned in the error state, to allow for disconnect
-    // and in the in-config states for registration
-    if (mState == STATE_CONSTRUCTED) {
-        ALOGE("%s: Stream %d: Can't return buffers in unconfigured state %d",
-                __FUNCTION__, mId, mState);
-        return INVALID_OPERATION;
-    }
-    if (mDequeuedBufferCount == 0) {
-        ALOGE("%s: Stream %d: No buffers outstanding to return", __FUNCTION__,
-                mId);
-        return INVALID_OPERATION;
+    if (output) {
+        // Output stream path
+        return Camera3OutputStream::returnBufferCheckedLocked(buffer,
+                                                              timestamp,
+                                                              output,
+                                                              releaseFenceOut);
     }
 
+    /**
+     * Input stream path
+     */
     bool bufferFound = false;
     sp<PinnedBufferItem> bufferItem;
     {
@@ -583,7 +213,7 @@
                 bufferFound = true;
                 bufferItem = tmp;
                 mBuffersInFlight.erase(it);
-                mDequeuedBufferCount--;
+                break;
             }
         }
     }
@@ -616,12 +246,19 @@
     bufferItem->getBufferItem().mFence = releaseFence;
     bufferItem.clear(); // dropping last reference unpins buffer
 
-    mCombinedFence = Fence::merge(mName, mCombinedFence, releaseFence);
-
-    mBufferReturnedSignal.signal();
+    *releaseFenceOut = releaseFence;
 
     return OK;
+}
 
+status_t Camera3ZslStream::returnInputBufferLocked(
+        const camera3_stream_buffer &buffer) {
+    ATRACE_CALL();
+
+    status_t res = returnAnyBufferLocked(buffer, /*timestamp*/0,
+                                         /*output*/false);
+
+    return res;
 }
 
 void Camera3ZslStream::dump(int fd, const Vector<String16> &args) const {
@@ -629,16 +266,11 @@
 
     String8 lines;
     lines.appendFormat("    Stream[%d]: ZSL\n", mId);
-    lines.appendFormat("      State: %d\n", mState);
-    lines.appendFormat("      Dims: %d x %d, format 0x%x\n",
-            camera3_stream::width, camera3_stream::height,
-            camera3_stream::format);
-    lines.appendFormat("      Usage: %d, max HAL buffers: %d\n",
-            camera3_stream::usage, camera3_stream::max_buffers);
-    lines.appendFormat("      Frames produced: %d, last timestamp: %lld ns\n",
-            mFrameCount, mLastTimestamp);
-    lines.appendFormat("      Total buffers: %d, currently dequeued: %d\n",
-            mTotalBufferCount, mDequeuedBufferCount);
+    write(fd, lines.string(), lines.size());
+
+    Camera3IOStreamBase::dump(fd, args);
+
+    lines = String8();
     lines.appendFormat("      Input buffers pending: %d, in flight %d\n",
             mInputBufferQueue.size(), mBuffersInFlight.size());
     write(fd, lines.string(), lines.size());
diff --git a/services/camera/libcameraservice/camera3/Camera3ZslStream.h b/services/camera/libcameraservice/camera3/Camera3ZslStream.h
index b863e7f..c7f4490 100644
--- a/services/camera/libcameraservice/camera3/Camera3ZslStream.h
+++ b/services/camera/libcameraservice/camera3/Camera3ZslStream.h
@@ -21,8 +21,7 @@
 #include <gui/Surface.h>
 #include <gui/RingBufferConsumer.h>
 
-#include "Camera3Stream.h"
-#include "Camera3OutputStreamInterface.h"
+#include "Camera3OutputStream.h"
 
 namespace android {
 
@@ -35,8 +34,7 @@
  * processing.
  */
 class Camera3ZslStream :
-        public Camera3Stream,
-        public Camera3OutputStreamInterface {
+        public Camera3OutputStream {
   public:
     /**
      * Set up a ZSL stream of a given resolution. Depth is the number of buffers
@@ -45,7 +43,6 @@
     Camera3ZslStream(int id, uint32_t width, uint32_t height, int depth);
     ~Camera3ZslStream();
 
-    virtual status_t waitUntilIdle(nsecs_t timeout);
     virtual void     dump(int fd, const Vector<String16> &args) const;
 
     enum { NO_BUFFER_AVAILABLE = BufferQueue::NO_BUFFER_AVAILABLE };
@@ -65,6 +62,8 @@
      */
     status_t clearInputRingBuffer();
 
+  protected:
+
     /**
      * Camera3OutputStreamInterface implementation
      */
@@ -76,41 +75,27 @@
     // Input buffers pending to be queued into HAL
     List<sp<RingBufferConsumer::PinnedBufferItem> > mInputBufferQueue;
     sp<RingBufferConsumer>                          mProducer;
-    sp<ANativeWindow>                               mConsumer;
 
     // Input buffers in flight to HAL
     Vector<sp<RingBufferConsumer::PinnedBufferItem> > mBuffersInFlight;
-    size_t                                          mTotalBufferCount;
-    // sum of input and output buffers that are currently acquired by HAL
-    size_t                                          mDequeuedBufferCount;
-    Condition                                       mBufferReturnedSignal;
-    uint32_t                                        mFrameCount;
-    // Last received output buffer's timestamp
-    nsecs_t                                         mLastTimestamp;
-
-    // The merged release fence for all returned buffers
-    sp<Fence>                                       mCombinedFence;
 
     /**
      * Camera3Stream interface
      */
 
-    // getBuffer/returnBuffer operate the output stream side of the ZslStream.
-    virtual status_t getBufferLocked(camera3_stream_buffer *buffer);
-    virtual status_t returnBufferLocked(const camera3_stream_buffer &buffer,
-            nsecs_t timestamp);
     // getInputBuffer/returnInputBuffer operate the input stream side of the
     // ZslStream.
     virtual status_t getInputBufferLocked(camera3_stream_buffer *buffer);
     virtual status_t returnInputBufferLocked(
             const camera3_stream_buffer &buffer);
 
-    virtual bool     hasOutstandingBuffersLocked() const;
-    virtual status_t disconnectLocked();
-
-    virtual status_t configureQueueLocked();
-    virtual size_t   getBufferCountLocked();
-
+    // Actual body to return either input or output buffers
+    virtual status_t returnBufferCheckedLocked(
+            const camera3_stream_buffer &buffer,
+            nsecs_t timestamp,
+            bool output,
+            /*out*/
+            sp<Fence> *releaseFenceOut);
 }; // class Camera3ZslStream
 
 }; // namespace camera3