
Transport Protocols Used for Streaming
The source data from a VN-Matrix encoder can be distributed to multiple displays/decoders
(one-to-many) or to a single display/decoder (point-to-point). A previously recorded stream
can be distributed in the same way and may be thought of as an encoder in this context.
A stream can be transported from the source (encoder, recorded stream) to the display
(decoder) using one of three methods:
•
Multicast Real-time Transport Protocol (RTP)
•
Unicast Real-time Transport Protocol (RTP)
•
Unicast Transmission Control Protocol (TCP)
These transport protocols are summarized in this section. For information on how to change
the transport protocol used by the VNM EC 200 (see
Multicast RTP — An Overview
Multicast Real-time Tranport Protocol (RTP) allows a source to be viewed on multiple
displays. This method uses a real-time variation of UDP (User Datagram Protocol).
SOURCE
DISPLAYS
RTP
RTP
RTP
RTP
RTP
RTP
Encoder sends data using RTP
to a multicast group.
Multiple decoders can be
part of the multicast group.
Network
VN-MATRIX 225 SERIES
RGB/DVI OVER IP
LAN-1
LAN-2
STATUS
VN-MATRIX 225 SERIES
RGB/DVI OVER IP
LAN-1
LAN-2
STATUS
VN-MATRIX 225 SERIES
RGB/DVI OVER IP
LAN-1
LAN-2
STATUS
VN-MATRIX 225 SERIES
RGB/DVI OVER IP
LAN-1
LAN-2
STATUS
VN-MATRIX 225 SERIES
RGB/DVI OVER IP
LAN-1
LAN-2
STATUS
Figure 3.
Multicast RTP Streaming
The source encoder uses RTP to send data to a multicast group. The source does not need
to know the IP address of the decoders that are using the source.
RTP provides very low latency which is important for video streaming. Unlike other
protocols, RTP packets include a time stamp. If packets are received in the wrong
order, they are sorted into the correct order for display or discarded if the time stamp is
out-of-date.
However, because RTP is a connectionless protocol, data delivery is not guaranteed. When
data packets are lost (for example, due to excessive network traffic) the VN-Matrix devices
carefully manage the data stream to minimize image disruption.
VNM EC 200 • Introduction
4
Summary of Contents for VNM EC 200
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