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

Media Data Atom TypesVideo MediaThere are two flavors of Motion-JPEG currently in use. These two formats differ based on their use of markers.Motion-JPEG format A supports markers; Motion-JPEG format B does not. The following paragraphs describehow QuickTime stores Motion-JPEG sample data. Figure 4-11 (page 172) shows an example of Motion-JPEG Adual-field sample data. Figure 4-12 (page 174) shows an example of Motion- JPEG B dual-field sample data.Figure 4-11Motion-JPEG A dual-field sample dataFirst fieldin sampleJPEG Start Of Image marker(Other markers, for example JFIF )Motion-JPEG APP 1 markerMarker content lengthReserved, set to zeroFF D8FF E100 2A00 00 00 00ByteoffsetsfromstartoffieldMotion-JPEG tag 'mjpg'Field sizePadded field sizeOffset to next fieldQuantization table offsetHuffman table offsetStart of Frame offsetStart of Scan offset (or zero)Start of data offset (or zero)Other markersJPEG DQT markerJPEG DHT markerJPEG SOF markerJPEG SOS markerJPEG entropy-coded dataJPEG EOI markerOptional padding with FFs6D 6A 70 67FF DB 00 84 .. ..FF C4 01 A2 .. ..FF C0 00 11 .. ..FF DA 00 0C.. .. .. ..FF D9FF FF FFNot in originalMotion-JPEGA specificationSecond fieldin sampleJPEG Start of image markerFF D8Motion-JPEG APP 1 markerOffset to next field, zero00 00 00 00Each field of Motion-JPEG format A fully complies with the ISO JPEG specification, and therefore supportsapplication markers. QuickTime uses the APP1 marker to store control information, as follows (all of the fieldsare 32-bit integers):2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.172