This soft copy for use by IBM employees only.
4.6 Video Distribution Module
The Video Distribution Module is a double-slot video concentrator module that
can be used to provide low-cost, high-quality, video distribution to standard TV
monitors. It has the following characteristics:
•Eight independently addressable MPEG-2 decoder ports. Each port can
support an MPEG-2 video stream encoded at data rates of 1.5-15 Mbps
simultaneously.
•Eight separate audio and video output connections:
−Video: composite baseband NTSC (EIA Standard RS-170A) or PAL (in
Release 1.1):
- Video Resolutions:
•SIF: 352x240 pixels (NTSC)
•HHR or Half-D1: 352x480 pixels (NTSC)
•CCIR-601 or Broadcast: 704x480 pixels (NTSC)
•Comparable PAL resolutions
−Audio: stereo, balanced or unbalanced
•Supports MPEG-2 Main Level, Main Profile (4:2:0) video and MPEG-1 audio.
•Supports MPEG-2 Elementary Stream or MPEG-1 Elementary Stream
encapsulated in an MPEG-2 Transport Stream at speeds of up to 15 Mbps.
•Supports a Single Program Transport Stream (that is, one video and one
audio program).
•Supports Closed Caption data and Extended Data Services information in
accordance with

EIA 608: Recommended Practice for Line 21

.
•Supports ATM for PVC and SVC Connections using UNI 3.1.
•Can receive video input from any ATM device that can access the 8285
switch via the the ATM network.
•Supports frame synchronization using GENLOCK inputs.
•Functions as an H.310 AAL-5 Receive-Only Terminal (ROT). H.310 is an ITU
standard for broadcast-quality audiovisual communication over broadband
networks using MPEG-2 video over high-speed ATM networks. The standard
includes subparts such as:
−H.262 (MPEG-2 video standard)
−H.222.0 (MPEG-2 Program and Transport Stream)
−H.222.1 (MPEG-2 streams over ATM)
−Various audio compression standards
•Can be monitored, but not configured via the 8285 ATM Control Point.
4.6.1 MPEG Fundamentals
MPEG-2 is an International Telecommunication Union (ITU) standard for
digitizing, compressing, and multiplexing video and audio information. The
predecessor to MPEG-2 is MPEG-1, which is widely used in low-end video and
PC software-based encoding and decoding environments. MPEG-1 is a desktop
48 ATM Workgroup Solutions: Implementing the 8285 ATM Switch