FOCUS Enhancements 3.2 - Manual (Page 143)

External Control Commands
129
mpgUnblack
This command uncovers MPEG video, reversing the effects of the
mpgBlack command.
To cover the video again, use the mpgBlack command.
Syntax
mpgUnblack 0 channel
Parameters
channel
The channel on the Firefly (0)
Return Values
This command returns ACK if mpgUnblack was started
successfully, or NAK if mpgUnblack could not be started.
Remarks
See mpgBlack on page 128 for more information on “blacking out”
video.