User`s manual

Alcorn McBride Digital Video Machine HD User’s Manual Rev 1.0
19
Special Playlist Commands
In addition to regular Digital Video Machine commands listed in the Command
Protocol section, there are a few additional commands for the Playlist Control
interface. These single-character commands further modify the behavior of the
playlists to provide additional features that only apply to the Playlist Control interface
of the DVMHD. These characters and their functions are listed in the following table:
Command Description
U
Uninterruptible. Causes the Digital Video Machine to ignore all
Input/Output Control triggers (with the exception of ‘Stop’) and any
‘Play’ commands. This behavior continues until the playlist
becomes interruptible once again using the ‘I’ command listed
below, or by the playlist ending.
I
Interruptible. Restores normal functionality to the Input/Output
Control interface as well as the ‘Play’ command. In this mode, all
commands can interrupt the playlist or cause it to advance to the
next playlist entry. This is the power-up default.
S
Seamless. Whenever PL commands are located immediately
after one another, the playlist will seamlessly transition between
video clips. Seamless playlist requires the use of the Play File
command. See the Command Protocol section for information
on how to use this command. This is the power-up default.
G
Segmented. In this mode, the playlist will not transition between
clips seamlessly. There will be a brief delay between clips.
W
Wait. Playlist waits until a ‘Resume’ input or a ‘Play’ command
occurs before moving on to the next playlist command. This is
useful for applications where a user decides when the playlist
should move on.
<
Loop. Tells the playlist to loop upon completion. This looping will
continue indefinitely until a Stop condition occurs, or another video
or playlist file is played.
;
Comment. Ignore all characters until the next line.
Commands may be entered into the Playlist in either upper or lower case. All text
following a semicolon (;) is interpreted as comments, until the next line in the file. You
may put anything you want in comments, including the special command characters
normally used in the Playlist.
One thing to be cautious of when making a playlist is creating an unintended endless
loop or uninterruptible wait. For example, if a Playlist contains a ‘U’ followed by a
Loop Play command, it doesn’t matter how many more tracks may occur in it, there is
no way to get to them! When using the ‘U’ command, always include an ‘I’ command
before the next Loop Play or W command, unless this is the desired behavior. Of
course, you can always terminate the loop or wait with a Stop command.