In 1.8 you'll be able to see notifications when a file start being played and when it's stopped. I think I also made it INFO in the log, so it should be easier to track back.
Petr Serviio developer / site admin Do not send me PM for support as the solution can't be shared with others.
Zip, is this what you were talking about [PlaybackEventsManager] Playback of media item 387742 has started at 0% on Identifier=192.168.0.224, Profile=Roku Media Player, Name=Roku Media Player