USB Picture Transfer Protocol (PTP) and Media Transfer Protocol (MTP)
Note: not to be confused with Precise Time Protocol -- All references in the code and filters are disambiguated as "USB-PTP" instead.
These are protocols used to communicate to digital cameras and media players.
A new dissector was created by Max Baker in the 1.9.1 timeframe. See https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=8431 and http://nikonhacker.com/viewtopic.php?t=708&f=2