# AndThen Engine

The `AndThen` engine is the same as the And engine, except for the following differences:

- Records in an input track must start after the record in the preceding input track. In other words, the `AndThen` engine enforces an additional TimestampCondition (in addition to any conditions that you specify):

  `start0 <= start1 <= start2 <= start3` (and so on).

- This engine is available only for processing video. It is not supported with images and documents.

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