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CMFormatDescriptionGetMediaSubType(_:)

Returns the media subtype of a format description.

Declaration

func CMFormatDescriptionGetMediaSubType(_ desc: CMFormatDescription) -> FourCharCode

Parameters

  • desc:

    The CMFormatDescription to examine.

Return Value

A media type that identifies the subtype of the CMFormatDescription.

Discussion

For audio streams, the media subtype is the asbd.mFormatID. For video streams, the media subtype is the video codec type. For muxed streams, it’s the format of the muxed stream.

For example, the function returns aac for a description of an AAC audio stream, avc1 for a description of an H.264 video stream, and mp2t for a description of an MPEG-2 transport (muxed) stream. If a media stream doesn’t have subtypes, this API may return 0.

See Also

Inspecting Format Descriptions