To upload a media file as an audio it must meet the following requirements.

Duration

The duration of the media file must not exceed 5 minutes.

Voice activity

The platform must detect at least 1 second of speech.

Format and codec

The format and codec of the media file must be decodable by FFmpeg.

You may click on the cards bellow to go to the appropriate sections of their website, where the supported formats and codecs are listed.