Extron Electronics VN-Matrix 200 Series - Manual (Page 76)

• CBR-F – The compression settings are dynamically modified to maintain the
transmit bandwidth at the specified rate. Additional refresh is added to maintain the
bandwidth as required. Filter averages bit rate over a period of one second.
• PBR-F – The compression settings are dynamically modified to limit the transmit
bandwidth to the specified rate or below. The specified compression setting is used as
the minimum compression value. Filter averages bit rate over a period of one second.
• CBR-DFM – Same as CBR-F except frames are dropped when a larger reduction than
can be achieved with just compression settings, is required.
• PBR-DFM – Same as PBR-F except frames are dropped when a larger reduction than
can be achieved with just compression settings, is required.
Flowrate control modes limit the instantaneous traffic on the network and are useful
where the network pipe between source and display has limited bandwidth and
drops traffic when this rate is exceeded. Non-flowrate control modes limit the average
bandwidth, but the instantaneous bandwidth can be high. Non-flowrate control modes
are best used on a LAN where the user does not wish the VNC 200 to consume excess
bandwidth.
NOTE: The actual bandwidth usage for Unicast transports will be multiplied by the
number of data stream destinations. For example, if the encoder has two
Unicast RTP connections plus a TCP connection, it will be sending three data
streams across the network.
Audio Compression
The S/PDIF digital data bus can carry two types of data:
• 2-channel (stereo) uncompressed audio, or
• Encoded digital data (typically AC-3 (Dolby Digital) format).
The VNC 200 supports limited compression of S/PDIF audio sources. This is controlled by
the
Compression setting on the Configure (audioPort) page. The following compression
options are available:
Compression 2 Channel Audio Source AC-3 Audio Source
No compression 24 bit native data
(2975 kBps)
24 bit native data
(2975 kBps)
Compress 1 16 bit data, full sample rate
(1517 kBps) 16 bit data, zeros run length encoded
(430 kBps)
Compress 2 16 bit data, 1/2 sample rate
(784 kBps) 16 bit data, zeros run length encoded
(430 kBps)
Compress 4 16 bit data, 1/4 sample rate
(418 kBps) 16 bit data, zeros run length encoded
(430 kBps)
NOTE: The native uncompressed setting passes the full 24 bit payload plus the
four S/PDIF control bits updating on a continuous frame basis. Other modes
only transmit 16 bit data and reduce the S/PDIF control bits update rate to
once per second.
VN-Matrix 200 Series • Advanced Setup Procedures 71