External Control Commands
mpgBlack
This command covers MPEG video on a channel, causing the corresponding video displays to go “black.” Note: This black may not be recognized by all displays as a true video signal.
To cover the video again, use the mpgUnblack command.
Syntax
mpgBlack 0 channel
Parameters
channel
The channel on the Firefly (0)
Return Values
This command returns ACK if mpgBlack was started successfully, or NAK if mpgBlack could not be started.
Remarks
Video playback is completely independent of whether the video is muted with mpgBlack. Videos will play “underneath” the black normally, audio will be unaltered and callbacks will be sent normally.
If a playlist is played with one of the commands, such as playlistPlay, unused channels (channels with no video files) will be set to the blackened state. Therefore, you must call mpgUnblack on those channels if you intend to play video on them with commands such as mpgLoad/mgpPlay.
See mpgUnblack for more information on “unblacking” video.
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