Alcorn Mcbride V+ series, Руководство пользователя

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7-6 Application Notes
want flexibility during installation to alter the timing between the two
theatres we will use nine separate DVD Players for the preshow.
The preshow audio is provided by two digital tracks sourced from the
Digital Binloop system.
Video Sync
It is important that the theatre DVD Players run in absolute frame
synchronization to guarantee that the audio program is started on the same
frame as the video program. This frame synchronization is achieved by
using BNC cables to daisy-chain the sync signal between the video players,
ending at the V16+ frame sync input. The sync works best when the V16+
is at the end of the line, with the 75 ohm terminator enabled using the
internal jumper.
When these frame sync signals are connected to multiple players the V16+
can guarantee that a play command issued to multiple players will be
processed by all players simultaneously, assuring that each player and the
Digital Binloop system will reproduce their source material in exact
synchronization.
Even though the Preshow and Theatre players source different video
programs, by keeping them in perfect synchronization we assure that the
Preshow and Theatre programs both begin at the same time. This makes for
a smooth transition between theatres.
In order to avoid audio synchronization problems, we could synchronize the
V16+, DVD Players and Digital Binloop Audio System to SMPTE
timecode by using an Alcorn McBride SMPTE Machine. Each of the
sequences in the V16+ could then be triggered at a preset SMPTE time
code, but for this installation there is no advantage in using this SMPTE
option since the V16+ and the players are always in agreement as to the
current frame time. The SMPTE option would be handy, though, if our
audio source were coming from a Tape Deck or other source that could
induce time variances that would affect show performance.
Let's not forget to distribute sync to the PLC and projector, also. This will
guarantee that the motion playback stays in sync with the projector and
audio tracks.
Houselights
A V16+ output commands the dimmer cabinet to lower the theatre
houselights for film projection. In an emergency situation, as well as at the
end of every show, the houselights are brought back up to their original
levels.
Printer
A serial printer can easily be connected to the show system to log the show
cycle and any errors. In our example, we will use a small thermal printer
(normally used in cash registers) to log system power-up.