diff --git a/media/libnblog/Timeline.cpp b/media/libnblog/Timeline.cpp
new file mode 100644
index 0000000..c09b03b
--- /dev/null
+++ b/media/libnblog/Timeline.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+#include <stddef.h>
+
+#include <audio_utils/roundup.h>
+#include <media/nblog/Timeline.h>
+
+namespace android {
+namespace NBLog {
+
+#if 0   // FIXME see note in Timeline.h
+NBLog::Timeline::Timeline(size_t size, void *shared)
+    : mSize(roundup(size)), mOwn(shared == NULL),
+      mShared((Shared *) (mOwn ? new char[sharedSize(size)] : shared))
+{
+    new (mShared) Shared;
+}
+
+NBLog::Timeline::~Timeline()
+{
+    mShared->~Shared();
+    if (mOwn) {
+        delete[] (char *) mShared;
+    }
+}
+#endif
+
+/*static*/
+size_t Timeline::sharedSize(size_t size)
+{
+    // TODO fifo now supports non-power-of-2 buffer sizes, so could remove the roundup
+    return sizeof(Shared) + roundup(size);
+}
+
+}   // namespace NBLog
+}   // namespace android