Cobalt Digital COMPASS 9822 Downconverter - Manual (Page 56)

3
9822 Function Submenu List and Descriptions
3-24 9822 PRODUCT MANUAL 9822-OM (V4.1)
(continued)
• Minimum Latency Control
Minimum Latency Frames Control
When Framesync is enabled, specifies the smallest amount of latency
allowed by the frame sync (latency measurement in output video frames).
The frame sync will not output a frame unless the specified number of
frames are captured in the buffer. The operational latency of the frame
sync is always between the specified minimum latency and
minimum latency plus one frame (not one field).
(Maximum range is 0 to 32.)
Note: Due to card memory limits, the maximum available Minimum
Latency Frames is related to the output video format selected.
For example, with a 525i59.94 output, the practical maximum limit
is 13.
When using this control, be sure to check the Framesync Status
display as follows:
• Latency frames selection within limits.
• Latency frames selection exceeds limits.
• Audio Hard Resync Threshold Control Sets threshold at which hard resync is applied if audio-video offset
exceeds threshold (see below). Hard resync provides fastest snyc-up
suitable for off-air manipulation. Conversely, a threshold setting high
enough to accommodate normal on-air offsets allows on-air resync that is
glitch-free.
(Range is 1.5 to 13.0 frames in 0.1 frame increments)
Table 3-2 9822 Function Submenu List — continued
Video:
40 msec
In this example, initial offset of 200 msec (appr. 6 frames) is
below 9 frame threshold and results in soft resync being
progressively applied.
t
Audio:
240 msec
With offset less than selected hard resync threshold, resync is progressively applied in many small
steps to provide a seamless, glitch-free retiming. After the successive steps, the audio is synchronized
with the video (in this example, 40 msec). (Progressive correction is applied at 1 msec/sec appr. rate.)
Video:
40 msec
t
Audio:
440 msec
With offset greater than selected hard resync
threshold, resync is immediately applied.
9 6
9
12
In this example, initial offset of 400 msec (appr. 12 frames) is
above 9 frame threshold and results in immediate hard resync.