Multiplexer preset options control how After Effects and Adobe Premiere Pro merge MPEG video and audio data into a single stream. The exact options available depend on the MPEG format you choose.

When you choose the MPEG‑2 format, all Multiplexer options provided by the MPEG standard are available for manual control. In most cases, it’s better to select an MPEG format specifically targeted to your output medium (such as MPEG‑2 DVD).

For more information on the options available, see the official web site of the MPEG organization at www.chiariglione.org/mpeg/.