Configuration and Tuning GPFS for Digital Media ... - IBM Redbooks

Table 1-1 shows the profile for CCTV environments.
Table 1-1 Close-Circuit Television (CCTV) profile
Close-Circuit Television
Streaming rate 0.384 / 1,5 Mbit/s
Access behavior Sequential for writing: random for reading
Block size used (application) Variable, depends on the application
Number of concurrent occurrences Small 1 - 10
Medium 10 - 50
Large 50 - ...
Read/write ratio 40/60%
Remarks Mostly write in parallel; read on-demand:
reverse/fast forward seeking->random
access
1.3.2 Video on demand (VoD)
Video-on-Demand’s goal is to enable individuals to select the video streams from
a central server for viewing on an end-user device, like television, computer
screen, or any other device capable of video streaming. VoD can be used for
entertainment, education, and video conferences. VoD requires a network
infrastructure that can handle the (large) amounts of data required for all
concurrent video streams. This contains the VoD infrastructure at the service
provider, as well as the network to reach the end user.
There are two different standards used (defined by the Society of Motion Pictures
Television Engineers - SMPTE):
► SDTV: Standard Definition TeleVision
SDTV provides a quality, which can be compared to a Digital Versatile Disk
(DVD). The vertical resolution of SD-TV is 480 lines, and has an aspect ratio
of 4:3 on screen.
► HDTV: High Definition TeleVision
HDTV provides a higher quality compared to SDTV. The vertical resolution
scales from 720 to 1080 lines and higher. The aspect ratio (width to height) is
defined as 16:9 (42 :32 ).
Table 1-2 on page 8 shows the profile for Video on demand (VoD) environments.
Chapter 1. Introduction to digital media 7