Extron electronics VN-Matrix 325, Руководство пользователя

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Typical bit rates
This section provides estimated bit rates for various video, audio, and error correction
selections and suggested mode (see “Bandwidth Management”, item
Ä
), selections.
The maximum supported bit rate is 300 Mbps, which is the total combined bit rate for
video, audio, and error correction data. The streams information area (figure 32 , item
Ä
)
of the bandwidth management standard controls panel shows the total transport bit rate as
adjustments are made to compression and FEC.
Table 7.
Typical Video Bit Rates
Application
•
Broadcast
contribution
•
Camera panning
•
Sports and nature
•
Lifestyle
•
Broadcast news
media gathering
•
Static camera frame
•
Interviews
•
Static camera frame
•
Surveillance
•
Telepresence
•
Collaboration
•
Video phone
Profile
•
High detail
•
High motion
•
High detail
•
Low motion
•
Low motion
•
No motion
Suggested
Mode (
A
)
PBR-F PBR-F (FD) Peak flow rate
Resolution
SDI 10 to 20 Mbps 3 to 10 Mbps 500 kbps to 3 Mbps
HD-SDI
50 to 90 Mbps 15 to 50 Mbps 2 to 15 Mbps
3G-SDI 100 to 180 Mbps 30 to 100 Mbps 4 to 30 Mbps
The VN-Matrix 325 supports the transport of the audio data that is embedded in the video
transport. Audio is available in blocks of 4 channels, with a bit rate of 2.43Mbps per pair
in stereo mode. Forward error correction, which implements the recommendations defined
by PRO-MPEG COP3, can be added to the audio stream to correct for packet drops on the
network. Be aware, though, that forward error correction can add up to 50-percent to the
bit rate overhead.
Table 8 defines the audio bit rates in Transparent mode.
Table 8 . Typical Embedded Audio Bit Rates in Transparent Mode
1 group
(4 channels)
2 group
(8 Channels)
3 group
(12 channels)
4 group
(16 Channels)
Audio bit rate 16 Mbps 32 Mbps 48 Mbps 64 Mbps
FEC overhead
(Example at 40%) 6 Mbps 12 Mbps 18 Mbps 24 Mbps
Total audio + FEC 22 Mbps 44 Mbps 66 Mbps 88 Mbps
The audio bit rate for Stereo mode is 2.3 Mbps. This can be further reduced with
compression (see “
ANC (Audio) Panel
“) and
item
î
.
Table 9 . Maximum bit rates
Application
•
Broadcast Contribution
•
Camera panning
•
Sports and nature
•
Lifestyle
•
Video Bit
rate
Audio bit rate
(1 group + 40%
[error correction])
Total
(max)
Resolution SD 10-20 Mbps 22 Mbps 42 Mbps
HD 50 to 90 Mbps 112 Mbps
3G 100 to 180 Mbps 202 Mbps
VN-Matrix 325 Serial Digital Over IP CODEC • Operation 46