VCR User Manual

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best with these resolutions.
Video format
The video format used and transmitted by the IP
VCR.
• NTSC
The IP VCR will favor transmitting video
at 30 frames per second, at SIF-like
resolutions.
• PAL
The IP VCR will favor transmitting video
at 25 frames per second, at CIF-like
resolutions.
NTSC is typically used in North America, while PAL
is typically used in the UK and Europe. Setting this
field to match the most common type of endpoint
used with the IP VCR will improve the smoothness
of the video sent by the IP VCR to the endpoints.
Regardless of how this setting is configured, the IP
VCR will accept video from endpoints at either
frame-rate.
Maximum
transmitted
video packet
size
The maximum payload size (in bytes) of the packets
sent by the IP VCR for outgoing video streams
(from the IP VCR to connected video endpoints).
Typically, you only need to set this value to lower
than the default (1400 bytes) if there was a known
packet size restriction in the path between the IP
VCR and potential connected endpoints.
Video streams generally contain packets of different
lengths. This parameter only sets the maximum size
of a transmitted network datagram. The IP VCR
optimally splits the video stream into packets of
this size or smaller. Thus, most transmitted packets
will not reach this maximum size.
Interlaced
video
optimization
Whether the IP VCR restricts video resolutions in
order to reduce the effect of interlacing artifacts.
You should only enable this option if you are seeing
video interlacing artifacts or on the advice of
Codian technical support. Note that all resolution
restrictions imposed by this setting apply only to
video being sent from endpoints to the IP VCR.
Video receive
bit rate
optimization
Enables the IP VCR to send bandwidth control
messages to optimize the video bandwidth being
used.
The IP VCR can send these messages to endpoints
requesting that the bandwidth of the video that they
are sending be decreased or increased, up to the
maximum bandwidth of the channel.
Flow control
on video
errors
Enables the IP VCR to request that the endpoint
send lower speed video if it fails to receive all the
packets which comprise the far end's video stream.
The IP VCR can send these messages to endpoints
requesting that the bandwidth of the video that they
are sending be decreased based on the quality of
video received by the IP VCR.
If there is a bandwidth limitation in the path
between the endpoint and the IP VCR, it is better
for the IP VCR to receive every packet of a lower
rate stream than to miss some packets of a higher
rate stream.
Audio and
video delay
equalization
When selected, audio will be delayed to be
transmitted at the same rate as video.
A setting used only to rectify some types of 'lip
sync' issues sometimes found with certain
endpoints. Leave at default setting, unless advised
to alter it by Codian technical support or a reseller.