Returns the media subtype of a
- iOS 4.0+
- macOS 10.7+
- UIKit for Mac 13.0+Beta
- tvOS 9.0+
- watchOS 6.0+Beta
- Core Media
Four-character code identifying the media subtype of the
The media subtype is defined in a media-specific way. For audio streams, the media subtype is the
asbd. For video streams, the media subtype is the video codec type. For muxed streams, it is the format of the muxed stream.
For example, 'aac ' is returned for a description of an AAC audio stream, 'avc1' is returned for a description of an H.264 video stream, and 'mp2t' is returned for a description of an MPEG-2 transport (muxed) stream. If a particular type of media stream does not have subtypes, this API may return 0.