diff --git a/services/audioflinger/AudioStreamOutSink.h b/services/audioflinger/AudioStreamOutSink.h
new file mode 100644
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--- /dev/null
+++ b/services/audioflinger/AudioStreamOutSink.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2012 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_AUDIO_STREAM_OUT_SINK_H
+#define ANDROID_AUDIO_STREAM_OUT_SINK_H
+
+#include <hardware/audio.h>
+#include "NBAIO.h"
+
+namespace android {
+
+// not multi-thread safe
+class AudioStreamOutSink : public NBAIO_Sink {
+
+public:
+    AudioStreamOutSink(audio_stream_out *stream);
+    virtual ~AudioStreamOutSink();
+
+    // NBAIO_Port interface
+
+    virtual ssize_t negotiate(const NBAIO_Format offers[], size_t numOffers,
+                              NBAIO_Format counterOffers[], size_t& numCounterOffers);
+    //virtual NBAIO_Format format();
+
+    // NBAIO_Sink interface
+
+    //virtual size_t framesWritten() const;
+    //virtual size_t framesUnderrun() const;
+    //virtual size_t underruns() const;
+
+    // This is an over-estimate, and could dupe the caller into making a blocking write()
+    // FIXME Use an audio HAL API to query the buffer emptying status when it's available.
+    virtual ssize_t availableToWrite() const { return mStreamBufferSizeBytes >> mBitShift; }
+
+    virtual ssize_t write(const void *buffer, size_t count);
+
+    // NBAIO_Sink end
+
+#if 0   // until necessary
+    audio_stream_out *stream() const { return mStream; }
+#endif
+
+private:
+    audio_stream_out * const mStream;
+    size_t              mStreamBufferSizeBytes; // as reported by get_buffer_size()
+};
+
+}   // namespace android
+
+#endif  // ANDROID_AUDIO_STREAM_OUT_SINK_H