JVC VN-V685U, 686U, 686BU MPEG-4 Stream Format Sent Out by VN-V685/686/686B, 20070319161455123UTC

2.5. MPEG-4 Stream Format Sent Out by VN-V685/686/686B

MPEG-4 stream from VN-V685/686/686B is MPEG-4 Part 2(ISO/IEC 14496-2) compliant, level 3 of simple profile. It is a sequence of I-VOPs, or I-VOPs and P-VOPs.

I-VOP: Intra frame compressed data

P-VOP: Inter frame compressed data with previous frame

Ratio of I-VOP and P-VOP depends on I-Frame interval setting. Encode page of Web has the setting.

First VOP can be I-VOP or P-VOP. If client want to decode from I-VOP, please skip P-VOP and wait first I-VOP.

Example of MPEG-4 stream

HTTP Response

P-VOP

P-VOP

P-VOP

VOL

I-VOP

P-VOP

There are VOL, Userdata1, GOV and Userdata2 before each I-VOP. In VN-V686 before v1.02, "Intelligent tarcking status" of Userdata2 is not available.

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-V685U	Product Name
Timestamp	Timestamp =	Year, Month, Day, Hour, Minute, Second,
	20070319161455123UTC	Millisedond, and Time zone
Camera ID	camera = Camera01	Camera ID that user can define

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