Table of Contents
Advertisement
Intelligent Disaster Recovery. An IDR frame is a special kind of I frame used in
IDR
encoding. IDR frames can be used to create Advanced Video Coding (AVC) streams, which can be
easily edited. See also
A lamp that allows an electric current to pass through a thin filament, heating it and causing it to emit
incandescent lamp
light.
Initialization frames
Initialization frames (IDRs or GDRs) are sent to endpoints that switch to a new source. This new source
sends the initialization frame to that endpoint, and to any endpoint that may already have been viewing
that source. These initialization frames are of lower quality than the P-frames that are used at all other
times. Because of this, endpoints that were already viewing that source will perceive a brief quality
flicker from that source.
IDRs are normally large, and would be unreasonably large if one was sent which matched the quality
of the normal P-frame. These unreasonably large IDRs are not generated because they would violate
the bandwidth provisioning for that video channel. GDRs (gradual decoder refresh frames) are now
used in place of IDRs to increase the quality of the switching picture at the expense of a slower refresh.
But, the quality of the GDR is still unable to reach that of the normal P-frame.
A device identifier on a TCP/IP network.
IP address
J
Variation in packet transit delay caused by queuing, contention, and serialization effects on the path
jitter
through the network. In general, higher levels of jitter are more likely to occur on either slow or heavily
jitter call
congested links.
jitter period
Jitter call is the average jitter measurement per call. Shown in the Jitter/Call output field as part of Per
Call Jitter and Packet Loss Reporting.
Jitter period is the interval between two times of maximum effect (or minimum effect) of a signal
characteristic that varies regularly with time. Jitter frequency, the more commonly quoted figure, is its
inverse.
The CTS measures jitter every 10 seconds. The Jitter/Period field reports the jitter measurement for the
last 10-second period.
The CTS calculates jitter as the sum of the maximum deviation (both late and early) from the expected
arrival time as given by the frame period. CMA computes frame jitter based on the arrival time of the
last packet of a frame.
L
Liquid crystal display. A projector for displaying video, images or computer data on a screen or other
LCD
flat surface.
Light-emitting diode. Indicators on the CTS that determine whether the user is sitting within camera
LED
range.
OL-13676-05
GDR
and
Initialization
frames.
Cisco TelePresence System Release 1.6 Administration Guide
Glossary
MPEG-4 AVC
GL-3
Advertisement
Table of Contents
Troubleshooting
