How do I automatically stop a composition at a specified length of time?

A composition can be run for a specified length of time via the use of a custom property that specifies the amount of time to run it before composition stop is issued.
  1. Open the composition, click the Properties tab in the lower panel, and select the Composition node in the Properties list.

  2. Once Composition is selected, click the Custom Properties tab.

  3. Click the green Plus (+) icon in the Custom Properties panel. The property form appears with the default name.

  1. Enter the custom property name "AutoStopTime" (no spaces in the name, and with that exact capitalization).

  2. Define the value for this Custom Property to be an integer number greater than or equal to 1000. This is an amount of time in milliseconds. So, for example, entering 60000 as the value will perform Stop at the one minute mark, while entering 3600000 will stop the composition at the one hour mark (and so forth). Naturally, the composition must be of a complexity to run at least as long as is specified in this property for that property to take effect.

When the specified time arrives, the following message will appear in the Composition’s Event Log:

Additionally, the Status Log widget will indicate the Stop request. The remainder of the displays and behavior will be the same as if the stop button had been pressed at the specified time. (This is not an abort). For more about this distinction, refer to Stopping a Composition.