update dvr comments

@@ -49,13 +49,13 @@ public:
     virtual ~SrsDvr();
 public:
     /**
-    * publish stream event, continue to write the m3u8,
-    * for the muxer object not destroyed.
+    * publish stream event, 
+    * when encoder start to publish RTMP stream.
     */
     virtual int on_publish(SrsRequest* req);
     /**
-    * the unpublish event, only close the muxer, donot destroy the 
-    * muxer, for when we continue to publish, the m3u8 will continue.
+    * the unpublish event.,
+    * when encoder stop(unpublish) to publish RTMP stream.
     */
     virtual void on_unpublish();
     /**
@@ -63,11 +63,11 @@ public:
     */
     virtual int on_meta_data(SrsAmf0Object* metadata);
     /**
-    * mux the audio packets to ts.
+    * mux the audio packets to dvr.
     */
     virtual int on_audio(SrsSharedPtrMessage* audio);
     /**
-    * mux the video packets to ts.
+    * mux the video packets to dvr.
     */
     virtual int on_video(SrsSharedPtrMessage* video);
 };