There are VOL, Userdata1, GOV and Userdata2 before each I-VOP.
　Data Structure before I-VOP
Item Note
VOL VOL of MPEG-4 Video
Userdata1 Reserved
GOV GOV of MPEG-4 Video
Userdata2 Userdata
　　Data Structure of Userdata2
Item Example Note
Start Code 0x000001B2 Start code of userdata in MPEG-4 Video
Product Name type = VN-V686U Product Name
Timestamp Timestamp =
20070319161455123UTC
Year, Month, Day, Hour, Minute, Second,
Millisedond, and Time zone
Camera ID camera = Camera01 Camera ID that user can define
Preset Position
Number
position = 0 Indicates preset position number after moving to
preset position. In other cases, position = NA.
Fan status fan = 0 Indicates status of fan. 1 means error.
Intelligent tracking
status
track_status = 0 Indicates status of Intelligent tracking. 0 means
completed, 1 means waiting for specifying target, 2 means
tracking, and 3 means losing.
3. API to Search VN-V686
VN-V686 in LAN can be searched by broadcast packet that includes this API.

Search VN-V686 in LAN

Protocol Send udp packet with following text in UDP payload to destination port number 80. Source port number
can be any value.
system.id<CRLF>
Response VN-V686 that received this packet sends udp packet to the source port number of the search packet.
UDP payload of response packet has model name, IP address, and subnet mask. VN-V686 waits 0-0.7 second before
sending response to avoid too many responses are sent in short period from many VN-V686s.
14
I-VOP
P-VOP
VOL