EVS XT2 - Choices of Bitrates When Using Avid Dnxhd or Apple Prores 422 with EVS XT[2] Servers

XT Series DISK RECORDER – Version 9 - Hardware Technical ReferenceIssue 5.00
EVS Broadcast Equipment SA – April 2008
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Apple ProRes 422 on EVS XT[2] servers is only available at these
bitrates.
1.5.7.3 CHOICES OF BITRATES WHEN USING AVID DNxHD® OR
APPLE PRORES 422 WITH EVS XT[2] SERVERS
H
OW TO READ THE FOLLOWING TABLES ?
1. Video Bitrate: value set by the user in the advanced parameters window
of the XT[2] server
2. Fields/Block: number of video fields that can be stored in one disk
block of 8MB, taking into account 8 audio tracks.
3. Actual Bandwidth: this is the actual disk/network bandwidth that is
required for the real time record or real time playback of one video
stream and its associated audio tracks.
4. Max. RT Channels: this is the maximum number of video channels (real
time record or real time playback) that one XT[2] server can support for
a given frame rate and bitrate. Since an XT[2] server can have a
maximum of 6 local video channels, any value higher than 6 means that
these additional real time access can be used over the XNet[2] SDTI
network.
For mixed configuration with standard and super motion channels on the
same server, the following rule must be used to ensure that the settings
do not exceed the maximum bandwidth of the server : (nbr of standard
channels x their actual bandwidth) + (nbr of super motion channels x
their actual bandwidth) must be lower or equal to 150 MB/s.
Example: Can I run an XT[2] server with 2 records (1 super motion + 1
standard) + 2 play (1 super motion + 1 standard) in Avid DNxHD® with a
video bitrate of 100Mbps in “PAL” ?
Calculation: 1 standard rec/play at 100Mbps uses 13.3 MB/s ; 1 super
motion record/play at 100Mbps uses 40.0 MB/s; 2 x 13.3 + 2 x 40.0 =
126.6 MB/s.
Conclusion: this configuration is supported.
5. Network transfers: the maximum bandwidth over the XNet[2] SDTI
network is approximately 110 MB/s. To determine the number of real
time transfers that can occur simultaneously over the network, this
number must be divided by the actual bandwidth given in the table for a
selected bitrate.
Example: How many real time transfers can I do over an XNet[2] SDTI
network (set at 1485Mbps) if I work with Apple ProRes 422 at 145Mbps
in “NTSC” ?