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10.5.
H.264 stream with motion/time SEI data
IQinVision has added additional information into H.264 streams as a User Data Unregistered Supplemental
Enhancement Information (SEI) messages. For additional information on SEI messages, refer to Annex D of
ITU-T H.264.
Note: IQinVision defined SEI messages are disabled by default and must be enabled by setting
oid 1.17.2.15 to 1.
The SEI
’
s are found in the first RTP packet of each frame and have the following format.
nal_length [2 bytes]
nal_code [1 byte]
sei_payload_type [1 byte if type is less than 256 bytes]
sei_payload_length [1 byte if length is less than 256 bytes]
uuid [16 bytes]
user_data [user_data_len]
rbsp_trailing_bits [1 byte]
The user data may contain multiple messages concatenated together. Each message has a type, length and
associated data bytes with the following format.
msg_type [1 byte]
msg_length [2 bytes]
msg_data [msg_length bytes]
For example, a frame with no motion would have an SEI with the format.
nal_length = 0x<nnnn> (length depends on data)
nal_code = 0x06 (SEI)
sei_payload_type = 0x05 (User data)
sei_payload_length = 0x37
uuid = 0x<nnnn> (16 bytes, camera specific)
msg_type = 0x01 (Pragma trigger message)
msg_length = 0x0014
msg_data = "Pragma: trigger=none"
msg_type = 0x02 (Timestamp message)
msg_length = 0x000d
msg_data = "1285697899672" (milliseconds since epoch)
rbsp_trailer = 0x80
