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Failing to accomplish optimal adjustment of the Picture noise level will result in either:
•
A large number of false alarms, or
•
Lack of alarm condition when the video is frozen
The Picture noise level and Picture freeze duration controls have been designed with the ability to detect
short-term "digital" freezes such as MPEG or motion JPEG server artifacts. When these devices have a
significant problem with the content that they are de-compressing, they will typically start to produce a
"blocky" effect. If the problem is severe enough, they will freeze a frame of video and play it out for a
number of frames. With the Picture noise level set to 1 (i.e. only detect exact, or nearly exact pictures)
and the Picture freeze duration set to minimum, the 7735AVC-LB can detect these quick "digital freezes."
The user cannot, however, detect both this type of freeze and a freeze from a link that has added noise to
the picture.
7.7.11. Detecting Picture Black Duration
Fault definitions
Picture black duration
4 to 900 frames
88 frames
7.8.
UTILITIES
7.8.1. Accessing Information About this Module and its Firmware
Utilities
About...
7.8.2. Data Logging
The RS-232 port on the Audio and Aux I/O connector is used for control and data logging of the status and
fault conditions. Control and data logging needs to be done with custom software that communicates with
the 7735AVC-LB card using the AVC Control/Status Protocol. For more information about configuring the
data logging output see section 7.8.2.
accompanies them from incoming VITC or from an internal clock.
There are 2 data logging options which can be enabled separately or at the same time:
•
Periodically output card status
•
Output fault data on a fault status change
7735AVC-LB Video Composite Encoder and Audio DAC with SoftSwitch
This control sets duration, in frames, of active picture content below 7
IRE that is considered a fault.
A fault is generated when the video level within the active picture area
falls below the preset black level (7 IRE) and remains for the specified
duration.
This menu item lists the particulars of this module and the firmware
residing within it. It gives quick access to information about revisions
that can be used to determine when upgrades are required.
When faults are logged on the serial port a time stamp
Revision 1.6
7700 MultiFrame Manual
7735AVC-LB - 33
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