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