Quicktime File Format (2012-08-14).pdf

Media Data Atom TypesVideo Media●●●●●“3D Media” (page 249) discusses briefly how QuickTime movies store 3D image data in a base media.“Streaming Media” (page 250) describes how streaming media is stored in a QuickTime file.“Hint Media” (page 251) describes the additions to the QuickTime file format for streaming QuickTimemovies over the Internet.“VR Media” (page 267) describes the QuickTime VR world and node information atom containers, as wellas cubic panoramas, which are new to QuickTime VR 3.0.“Movie Media” (page 310) discusses movie media which is used to encapsulate embedded movies withinQuickTime movies.Video MediaVideo media is used to store compressed and uncompressed image data in QuickTime movies. It has a mediatype of 'vide'.Video Sample DescriptionThe video sample description contains information that defines how to interpret video media data. A videosample description begins with the four fields described in “General Structure of a Sample Description” (page100).Note Some video sample descriptions contain an optional 4-byte terminator with all bytes set to0, following all other sample description and sample description extension data. If this optionalterminator is present, the sample description size value will include it. It is important to check thesample description size when parsing: more than or fewer than these four optional bytes, if presentin the size value, indicates a malformed sample description.The data format field of a video sample description indicates the type of compression that was used to compressthe image data, or the color space representation of uncompressed video data. Table 4-1 (page 155) showssome of the formats supported. The list is not exhaustive, and is subject to addition.Table 4-1Some image compression formatsCompression type'cvid''jpeg''smc 'DescriptionCinepakJPEGGraphics2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.155