Encapsulates an Audio.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v25/resources/media_file.proto)

| Fields ||
|---|---|
| ## `ad_duration_millis` | `int64` Output only. The duration of the Audio in milliseconds. |