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Utility Classes

There are three classes belonging to this group: QTCompressionOptions, QTFormatDescription, and QTSampleBuffer. These are best characterized as utility classes, in that they perform tasks related to representing, for example, the compressions for particular media, or describing the formats of various media samples.

You can use QTCompressionOptions to describe compression options for all kinds of different media, using the compressionOptionsIdentifiersForMediaType: and mediaType methods. Compression options are created from presets keyed by a named identifier. These preset identifiers are listed in the QuickTime Kit Framework Reference in the chapter describing this class.

Using QTSampleBuffer objects, you can get information about sample buffer data that you may need to output or process the media samples in the buffer.

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