Grass Valley iTX System v.2.6 - Manual (Page 256)

Working with iTX services on an Output Server machine
When this synchronisation occurs, the SDI video card drops or repeats frames from the video
input signal.
1.
Do one of the following to set the horizontal output timing.
• In the Horizontal box, enter the output timing value.
• Move the Horizontal slider to select the output timing value.
2. Do one of the following to set the vertical output timing.
• In the Vertical box, enter the output timing value.
• Move the Vertical slider to select the output timing value.
3. Click Save.
Specify a number of frames for the output buffer on the Output Server SDI video
card
To ensure it delivers a smooth output, iTX temporarily stores processed frames in an output
buffer on the SDI video card before playing them out. This gives it time to process successive
frames of video before they are needed for playout.
The default size of the buffer is normally 10 frames; this satisfies most playout requirements.
Sometimes, such as when iTX has to do a lot of complex video processing, it may be necessary
to set a different value. You can do this on the Number of Output Buffers panel.
1.
Do one of the following to set the size of the output buffer.
• In the Output Buffer box, enter the required number of frames.
• Drag the Output Buffer slider to select the required number of frames.
2. Click Save.
Important:
• Before changing the buffer size, you should contact iTX Support and discuss the effects
of the change on system performance.
Adjust the timing of the internal video processing
Use of the output buffer on the SDI video card introduces a small delay in the timing of the
output. For instance, any particular video frame may play out a few frames after its actual
scheduled time. Although it is possible to adjust the internal video processing to remove this
delay, in most playout situations it is not necessary to do so.
The output timing is of more importance for transitions, such as when switching the output of a
master channel into and out of regional sub-channels. For accurate transitions, the internal
processing may need adjusting to take account of the throughput time of a live source.
You can cause iTX to process video earlier or later by up to 30 frames by using the controls on
the Frames Delay For Time Sync panel.
1.
Do one of the following to adjust the timing of the internal processing.
• In the number box, enter the required number of frames (between -30 and 30).
• Drag the slider to select the required number of frames.
2. Click Save.
March 2015 System Administrator Guide Page 256 of 404