Means that all packets for a video on demand (VOD) file being streamed by the client came from an already cached copy of that file.
Means that while the client was streaming a VOD file, it caused the proxy to fetch some as yet uncached part of the VOD file from the online content server (OCS).
Note that, only streaming data activity and not streaming control activity is used to determine hit/miss etc.
Means that the client streaming a VOD file was handled in passthrough mode.
For Windows Media (WM-RTSP, WM-HTTP, MMS), access logging happens for every play spurt, because the player sends a log record for every play spurt. So the above explanation is in the context of every play spurt. In RealMedia, access logging happens only once for a client session, because the client sends only one log record at the end of the session. So this explanation would apply for the entire session.