The following procedure uses the Media Control Interface to play a video file.
TO PLAY.AVI IGNORE MCI [open c:\\windows\\clock.avi alias clock] MCI [play clock] WAIT 120 MCI [pause clock] WAIT 120 MCI [resume clock] WAIT 720 MCI [close clock] END
Let's take a closer look at each instruction in the example above.
The procedure first opens "c:\windows\clock.avi" by issuing an
We use the
alias parameter so that we can refer to this media entity as
clock instead of always using the full path to clock.avi.
Unlike most other commands, the
open command outputs a value on success.
Since Logo programs must do something with every value that is output, we simply IGNORE it.
play command is used to start playing from one time to another.
The video plays asynchornously, which means that FMSLogo doesn't wait for the video to finish playing before running the next instruction.
If you wanted to wait until the track was done before moving on to the next instruction, you could add
wait to the end of the MCI instruction, as in:
MCI [play clock wait]
The WAIT instructions just waits for some amount of time. They have nothing to do with MCI, they just gives you some time to see the result of the previous MCI command.
resume commands are used to pause and unpause the video.
close command is used to tell the Media Control Interface that you are done with the video file.
This closes the window in which the video was playing.