Update comments

Change-Id: I37d3c4ce22b74fe8581a886fe5a7f9fef8266dad
diff --git a/include/private/media/AudioTrackShared.h b/include/private/media/AudioTrackShared.h
index 7143f1a..5644428 100644
--- a/include/private/media/AudioTrackShared.h
+++ b/include/private/media/AudioTrackShared.h
@@ -53,8 +53,8 @@
 struct AudioTrackSharedStreaming {
     // similar to NBAIO MonoPipe
     // in continuously incrementing frame units, take modulo buffer size, which must be a power of 2
-    volatile int32_t mFront;    // read by server
-    volatile int32_t mRear;     // write by client
+    volatile int32_t mFront;    // read by consumer (output: server, input: client)
+    volatile int32_t mRear;     // written by producer (output: client, input: server)
     volatile int32_t mFlush;    // incremented by client to indicate a request to flush;
                                 // server notices and discards all data between mFront and mRear
     volatile uint32_t mUnderrunFrames;  // server increments for each unavailable but desired frame