IBM SG24-4817-00 Configuring the Video Distribution Module, Feature, + P Frame, IPB Frame

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Table 4. Video Distribution Module Comparison of MPEG-2 and Motion-JPEG

Feature	MPEG-2		M-JPEG
System Layer	Provides audio and video		No system layer, that is,
	synchronization.		no standard
			synchronization method.
Record on Servers	Yes		Must record video and
			audio separately, leading
			to synchronization
			problems.
Motion Compression	Yes		No
Standard Auto	Yes		No
Compression
Compression Algorithm	DCT		DCT
MPEG-1 Compatibility	System layer can carry		No
	MPEG-1. MPEG-2
	equipment downward
	compatible with MPEG-1.
Private Data for Closed	Yes		No
Captioning
Bandwidth Requirements	I-Frame	Less	20 Mbps
for High Quality Video		than 18
		Mbps.
	I + P Frame	Less
		than 12
		Mbps.
	IPB Frame	Less
		than
		6-8
		Mbps.
ATM Compatibility	MPEG-2 Transport		Requires circuit-switched,
	Streams can be carried		constant bit rate (AAL1)
	over AAL5 and can take		services for accurate
	advantage of variable bit		voice and video
	rate services.		synchronization.
Standardization	MPEG-2 video and		Video conferencing and
	MPEG-1 audio encoding		transmission using
	are standard.	H.310	M-JPEG is not
	encompasses MPEG-2		standardized.
	and defines operational		Proprietary
	specifications for MPEG-2		implementations cause
	over ATM video		interoperability problems.
	conferencing.

4.6.2 Configuring the Video Distribution Module

The Video Distribution Module is a relatively simple module to configure since it is merely a target for an ATM stream from another source. The process is as follows:

•Enable the VDM port as a UNI interface: In the following example:

−The second port of the VDM for our video output is set.

52ATM Workgroup Solutions: Implementing the 8285 ATM Switch