Modes

You can specify a fixed amount of time (in HH:MM:SS format), which will be counted from the time you start the timer.

You can directly specify the time at which the countdown should end.

You can specify how many tracks iTunes should play before the countdown stops. This prevents that the end of playback falls into the middle of a track. The number of tracks you set up doesn't include the currently playing track, so if you set up "1 track" it'll stop after the next track.

You can specify that the countdown should end when the DVD has finished playing.

You can specify that the countdown should end when the Quicktime movie has finished playing.