diff --git a/media/libaudiohal/impl/StreamHalHidl.cpp b/media/libaudiohal/impl/StreamHalHidl.cpp
index c08dddb..2726e36 100644
--- a/media/libaudiohal/impl/StreamHalHidl.cpp
+++ b/media/libaudiohal/impl/StreamHalHidl.cpp
@@ -299,10 +299,17 @@
         if (mCallback.unsafe_get()) {
             processReturn("clearCallback", mStream->clearCallback());
         }
+#if MAJOR_VERSION >= 6
+        if (mEventCallback.unsafe_get() != nullptr) {
+            processReturn("setEventCallback",
+                    mStream->setEventCallback(nullptr));
+        }
+#endif
         processReturn("close", mStream->close());
         mStream.clear();
     }
     mCallback.clear();
+    mEventCallback.clear();
     hardware::IPCThreadState::self()->flushCommands();
     if (mEfGroup) {
         EventFlag::deleteEventFlag(&mEfGroup);
@@ -614,6 +621,50 @@
 }
 #endif
 
+#if MAJOR_VERSION < 6
+status_t StreamOutHalHidl::setEventCallback(
+        const sp<StreamOutHalInterfaceEventCallback>& callback __unused) {
+    // Codec format callback is supported starting from audio HAL V6.0
+    return INVALID_OPERATION;
+}
+#else
+
+#include PATH(android/hardware/audio/FILE_VERSION/IStreamOutEventCallback.h)
+
+namespace {
+
+struct StreamOutEventCallback : public IStreamOutEventCallback {
+    StreamOutEventCallback(const wp<StreamOutHalHidl>& stream) : mStream(stream) {}
+
+    // IStreamOutEventCallback implementation
+    Return<void> onCodecFormatChanged(
+            const android::hardware::hidl_vec<uint8_t>& audioMetadata)  override {
+        sp<StreamOutHalHidl> stream = mStream.promote();
+        if (stream != nullptr) {
+            std::basic_string<uint8_t> metadataBs(audioMetadata.begin(), audioMetadata.end());
+            stream->onCodecFormatChanged(metadataBs);
+        }
+        return Void();
+    }
+
+  private:
+    wp<StreamOutHalHidl> mStream;
+};
+
+}  // namespace
+
+status_t StreamOutHalHidl::setEventCallback(
+        const sp<StreamOutHalInterfaceEventCallback>& callback) {
+    if (mStream == nullptr) return NO_INIT;
+    mEventCallback = callback;
+    status_t status = processReturn(
+            "setEventCallback",
+            mStream->setEventCallback(
+                    callback.get() == nullptr ? nullptr : new StreamOutEventCallback(this)));
+    return status;
+}
+#endif
+
 void StreamOutHalHidl::onWriteReady() {
     sp<StreamOutHalInterfaceCallback> callback = mCallback.promote();
     if (callback == 0) return;
@@ -635,6 +686,13 @@
     callback->onError();
 }
 
+void StreamOutHalHidl::onCodecFormatChanged(const std::basic_string<uint8_t>& metadataBs) {
+    sp<StreamOutHalInterfaceEventCallback> callback = mEventCallback.promote();
+    if (callback == nullptr) return;
+    ALOGV("asyncCodecFormatCallback %s", __func__);
+    callback->onCodecFormatChanged(metadataBs);
+}
+
 
 StreamInHalHidl::StreamInHalHidl(const sp<IStreamIn>& stream)
         : StreamHalHidl(stream.get()), mStream(stream), mReaderClient(0), mEfGroup(nullptr) {
diff --git a/media/libaudiohal/impl/StreamHalHidl.h b/media/libaudiohal/impl/StreamHalHidl.h
index f587889..88f8587 100644
--- a/media/libaudiohal/impl/StreamHalHidl.h
+++ b/media/libaudiohal/impl/StreamHalHidl.h
@@ -173,6 +173,11 @@
     void onDrainReady();
     void onError();
 
+    status_t setEventCallback(const sp<StreamOutHalInterfaceEventCallback>& callback) override;
+
+    // Methods used by StreamCodecFormatCallback (HIDL).
+    void onCodecFormatChanged(const std::basic_string<uint8_t>& metadataBs);
+
   private:
     friend class DeviceHalHidl;
     typedef MessageQueue<WriteCommand, hardware::kSynchronizedReadWrite> CommandMQ;
@@ -180,6 +185,7 @@
     typedef MessageQueue<WriteStatus, hardware::kSynchronizedReadWrite> StatusMQ;
 
     wp<StreamOutHalInterfaceCallback> mCallback;
+    wp<StreamOutHalInterfaceEventCallback> mEventCallback;
     sp<IStreamOut> mStream;
     std::unique_ptr<CommandMQ> mCommandMQ;
     std::unique_ptr<DataMQ> mDataMQ;
diff --git a/media/libaudiohal/impl/StreamHalLocal.cpp b/media/libaudiohal/impl/StreamHalLocal.cpp
index 4818fd8..69be303 100644
--- a/media/libaudiohal/impl/StreamHalLocal.cpp
+++ b/media/libaudiohal/impl/StreamHalLocal.cpp
@@ -275,6 +275,43 @@
     return mStream->get_mmap_position(mStream, position);
 }
 
+status_t StreamOutHalLocal::setEventCallback(
+        const sp<StreamOutHalInterfaceEventCallback>& callback) {
+    if (mStream->set_event_callback == nullptr) {
+        return INVALID_OPERATION;
+    }
+    stream_event_callback_t asyncCallback =
+            callback == nullptr ? nullptr : StreamOutHalLocal::asyncEventCallback;
+    status_t result = mStream->set_event_callback(mStream, asyncCallback, this);
+    if (result == OK) {
+        mEventCallback = callback;
+    }
+    return result;
+}
+
+// static
+int StreamOutHalLocal::asyncEventCallback(
+        stream_event_callback_type_t event, void *param, void *cookie) {
+    // We act as if we gave a wp<StreamOutHalLocal> to HAL. This way we should handle
+    // correctly the case when the callback is invoked while StreamOutHalLocal's destructor is
+    // already running, because the destructor is invoked after the refcount has been atomically
+    // decremented.
+    wp<StreamOutHalLocal> weakSelf(static_cast<StreamOutHalLocal*>(cookie));
+    sp<StreamOutHalLocal> self = weakSelf.promote();
+    if (self == nullptr) return 0;
+    sp<StreamOutHalInterfaceEventCallback> callback = self->mEventCallback.promote();
+    if (callback.get() == nullptr) return 0;
+    switch (event) {
+        case STREAM_EVENT_CBK_TYPE_CODEC_FORMAT_CHANGED:
+            callback->onCodecFormatChanged(std::basic_string<uint8_t>((uint8_t*)param));
+            break;
+        default:
+            ALOGW("%s unknown event %d", __func__, event);
+            break;
+    }
+    return 0;
+}
+
 StreamInHalLocal::StreamInHalLocal(audio_stream_in_t *stream, sp<DeviceHalLocal> device)
         : StreamHalLocal(&stream->common, device), mStream(stream) {
 }
diff --git a/media/libaudiohal/impl/StreamHalLocal.h b/media/libaudiohal/impl/StreamHalLocal.h
index 34f2bd8..d17f9f3 100644
--- a/media/libaudiohal/impl/StreamHalLocal.h
+++ b/media/libaudiohal/impl/StreamHalLocal.h
@@ -156,9 +156,12 @@
     // Called when the metadata of the stream's source has been changed.
     status_t updateSourceMetadata(const SourceMetadata& sourceMetadata) override;
 
+    status_t setEventCallback(const sp<StreamOutHalInterfaceEventCallback>& callback) override;
+
   private:
     audio_stream_out_t *mStream;
     wp<StreamOutHalInterfaceCallback> mCallback;
+    wp<StreamOutHalInterfaceEventCallback> mEventCallback;
 
     friend class DeviceHalLocal;
 
@@ -168,6 +171,8 @@
     virtual ~StreamOutHalLocal();
 
     static int asyncCallback(stream_callback_event_t event, void *param, void *cookie);
+
+    static int asyncEventCallback(stream_event_callback_type_t event, void *param, void *cookie);
 };
 
 class StreamInHalLocal : public StreamInHalInterface, public StreamHalLocal {