diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h
index 9f631cf..8afcc5d 100644
--- a/include/media/AudioTrack.h
+++ b/include/media/AudioTrack.h
@@ -123,6 +123,8 @@
      *  - NO_ERROR: successful operation
      *  - NO_INIT: audio server or audio hardware not initialized
      *  - BAD_VALUE: unsupported configuration
+     * frameCount is guaranteed to be non-zero if status is NO_ERROR,
+     * and is undefined otherwise.
      */
 
     static status_t getMinFrameCount(size_t* frameCount,