4. Operating
Barco – TransForm A - X Terminal – DOC-3265-2 – user's manual – Revision 09 – September-2006
_____________________________________________________
4-12
4.6
Displaying video and RGB signals
Video and RGB signals can be displayed on an Barco
display wall with the optional input cards Q
UAD
A
NALOG
V
IDEO
C
ARD
, S
TREAMING
V
IDEO
C
ARD
,
Q
UAD
SDI
V
IDEO
C
ARD
and D
UAL
RGB
I
NPUT
C
ARD
. Based on an extension library of the
X server the Barco video client
xvideo
allows the convenient handling of analog video, streaming video and
RGB signals.
Simultaneous operation
Multiple input cards can be operated simultaneously. In this case, the corresponding video windows may freely
overlap. For larger display walls a system with multiple O
MNI
B
US
devices may be required. Large systems with
freely movable video and RGB windows require the usage of a distributed system.
OmniScaler
Due to the dual color mode capability of the O
MNI
S
CALER
, T
RANS
F
ORM
A can display video and RGB signals in their
native color mode e.g. YUV4:2:2 and 16 bit RGB TrueColor while the X Server operates in 8 bit PseudoColor mode
with 256 colors. Please, refer to section
for more details.
One O
MNI
S
CALER
provides the capability to process up to 128 video and RGB inputs simultaneously. Video and RGB
data is triple buffered. Therefore only entire frames are displayed in sync with the graphical data to avoid frame
tearing.
Backend scaling
The O
MNI
S
CALER
is able to do backend scaling. Scaling the video data at the backend of data transfer chain (Input
card -> PCI-Bus -> O
MNI
S
CALER
) has its big advantage in a reduced need of PCI Bus bandwidth. Furthermore the
O
MNI
S
CALER
provides up-scaling capabilities until full-screen resolution and far beyond.
The backend scaling uses linear interpolation for calculating new pixels.
In standard configuration the X server, depending on the size of the video window and the type of the input card
automatically controls the usage of backend scaling.
Dependant on the scaling factor either the O
MNI
S
CALER
or the input card scales data. As soon as the size of the
video or RGB window is larger than 1:1 the O
MNI
S
CALER
scales data up to the displayed size. If the video is dis-
played in a lower resolution than 1:1, then the input card itself performs a downscaling, to reduce the need of
bandwidth for the data transfer.
Module video
The Q
UAD
A
NALOG
V
IDEO
C
ARD
, S
TREAMING
V
IDEO
C
ARD
, Q
UAD
SDI
V
IDEO
C
ARD
and the D
UAL
RGB
I
NPUT
C
ARD
also display
videos and RGB signals respectively without borders and fitted to complete projection modules (1 to n×n, de-
pending on configuration). The display is always »on top«, other applications are »behind« and can not be ma-
nipulated by accident. If the display is removed from the desktop (quit or iconified) all covered applications show
up again immediately.
In a distributed system the display wall is controlled by multiple rendering machines. If a
video shall be displayed on the display areas of multiple rendering machines, all concerned
rendering machines must be supplied with the video signal.
