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

Media Data Atom TypesVideo MediaNote The last two fields have been added since the original Motion-JPEG specification, and so theymay be missing from some Motion-JPEG A files. You should check the length of the APP1 markerbefore using the start of scan offset and start of data offset fields.Motion-JPEG format B does not support markers. In place of the marker, therefore, QuickTime inserts a headerat the beginning of the bitstream. Again, all of the fields are 32-bit integers.Figure 4-12Motion-JPEG B dual-field sample dataFirst field in sampleMotion-JPEG marker (no header)Reserved, set to zeroMotion-JPEG tag 'mjpg'00 00 00 006D 6A 70 67ByteoffsetsfromstartoffieldField sizePadded field sizeOffset to next fieldQuantization table offsetHuffman table offsetStart of Frame offsetStart of Scan offset (or zero)Start of data offset (or zero)Padding with zeros to 16-byte boundary 00 00Quantization table data 00 84Optional padding with zeros 00 00 .. ..Huffman table dataStart of Frame dataStart of Scan dataJPEG entropy-coded data a (not byte-stuffed)Padding with zeros to 16-byte boundary01 A2 .. ..00 11 .. ..00 0C .. .... .. .. ..00 00 00Second field in sampleMotion JPEG markerOffset to next field, zero 00 00 00 002012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.174