diff --git a/services/audioflinger/AudioStreamInSource.cpp b/services/audioflinger/AudioStreamInSource.cpp
new file mode 100644
index 0000000..8b4bebf
--- /dev/null
+++ b/services/audioflinger/AudioStreamInSource.cpp
@@ -0,0 +1,83 @@
+/*
+ * 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.
+ */
+
+#define LOG_TAG "AudioStreamInSource"
+//#define LOG_NDEBUG 0
+
+#include <cutils/compiler.h>
+#include <utils/Log.h>
+#include "AudioStreamInSource.h"
+
+namespace android {
+
+AudioStreamInSource::AudioStreamInSource(audio_stream_in *stream) :
+        NBAIO_Source(),
+        mStream(stream),
+        mStreamBufferSizeBytes(0),
+        mFramesOverrun(0),
+        mOverruns(0)
+{
+    ALOG_ASSERT(stream != NULL);
+}
+
+AudioStreamInSource::~AudioStreamInSource()
+{
+}
+
+ssize_t AudioStreamInSource::negotiate(const NBAIO_Format offers[], size_t numOffers,
+                                      NBAIO_Format counterOffers[], size_t& numCounterOffers)
+{
+    if (mFormat == Format_Invalid) {
+        mStreamBufferSizeBytes = mStream->common.get_buffer_size(&mStream->common);
+        audio_format_t streamFormat = mStream->common.get_format(&mStream->common);
+        if (streamFormat == AUDIO_FORMAT_PCM_16_BIT) {
+            uint32_t sampleRate = mStream->common.get_sample_rate(&mStream->common);
+            audio_channel_mask_t channelMask =
+                    (audio_channel_mask_t) mStream->common.get_channels(&mStream->common);
+            mFormat = Format_from_SR_C(sampleRate, popcount(channelMask));
+            mBitShift = Format_frameBitShift(mFormat);
+        }
+    }
+    return NBAIO_Source::negotiate(offers, numOffers, counterOffers, numCounterOffers);
+}
+
+size_t AudioStreamInSource::framesOverrun()
+{
+    uint32_t framesOverrun = mStream->get_input_frames_lost(mStream);
+    if (framesOverrun > 0) {
+        mFramesOverrun += framesOverrun;
+        // FIXME only increment for contiguous ranges
+        ++mOverruns;
+    }
+    return mFramesOverrun;
+}
+
+ssize_t AudioStreamInSource::read(void *buffer, size_t count)
+{
+    if (CC_UNLIKELY(mFormat == Format_Invalid)) {
+        return NEGOTIATE;
+    }
+    ssize_t bytesRead = mStream->read(mStream, buffer, count << mBitShift);
+    if (bytesRead > 0) {
+        size_t framesRead = bytesRead >> mBitShift;
+        mFramesRead += framesRead;
+        return framesRead;
+    } else {
+        return bytesRead;
+    }
+}
+
+}   // namespace android