EVS XT2+, Техническое руководство по аппаратному обеспечению

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Issue
10.05.A
XT2+ Series DISK RECORDER – Version 10.05 - Hardware Technical Reference
EVS Broadcast Equipment SA – July 2011
24
I
MPORTANT
R
ECOMMENDATIONS
• For 6-channel configuration, maximum bitrates for Avid DNxHD® or Apple
ProRes 422 should be 220Mbps (NTSC) or 185Mbps (PAL).
• “Super 1 Cam” configuration (i.e. 1 Super Motion REC + 1 Std REC +
1 Super Motion PLAY + 1 Std PLAY): maximum bitrates for Avid DNxHD® or
Apple ProRes 422 should be 145Mbps (NTSC) or 185Mbps (PAL).
• When using the Avid DNxHD® codec, we advise to work at 100Mbps if the
picture quality is satisfactory

the XT2+ can sustain 6 local ch 5
network transfers.
• The 4ch configurations with 3D, 1080p or 3D SLSM 3x are only possible with
Avid DNxHD® 100 Mbps or Apple ProRes 422 LT.
1.8.8 R
AID LEVEL
: 3
The Video Raid uses striping process across 5 or 6 disk drives. The video and
audio data is striped over the first 4 or 5 drives while the parity information is
saved on the fifth or sixth drive. If one drive is damaged, the Video Raid can use
the parity information to recover the missing information, so that operation can
continue seamlessly without bandwidth loss.
For more information on online rebuild, refer to the section dedicated to this
subject in the XT2+ Software Technical Reference manual.
1.8.9 I
NTERPOLATION
The playing back of smooth slow motion pictures carries specific issues: since
some fields must be repeated at regular interval to provide the video at the
playback speed required by the operator, parity violation appears regularly on the
output video signal. This issue is specific to interlaced formats (525i, 625i and
1080i) and does not concern progressive formats (720p and 1080p).
If
O
and
E
represent respectively the odd and even fields of a standard video
signal (50/60 Hz), we have:
The original video signal:
O E O E O E O E O E O E O E O E
The output video signal at 50% speed:
O O E E O O E E O O E E O O E E
The output video signal at 33% speed:
O O O E E E O O O E E E O O O E
The output video signal at 25% speed :
O O O O E E E E O O O O E E E E
Fields with parity violation are shown in bold, underlined letters. As it appears
from the above table, whatever the playback speed (with the exception of the
normal 100% playback speed), a number of fields violate the normal parity of the
output signal. This parity violation induces a 1-line shift of the field, resulting in a
vertical jitter of the picture. The jitter frequency depends upon the chosen
playback speed.