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

Media Data Atom TypesVideo MediaReservedUnpredictable; should be set to 0.TagThe data type; this field must be set to 'mjpg'.Field sizeThe actual size of the image data for this field, in bytes.Padded field sizeThe size of the image data, including pad bytes. Some video hardware may append pad bytes to theimage data; this field, along with the field size field, allows you to compute how many pad bytes wereadded.Offset to next fieldThe offset, in bytes, from the start of the field data to the start of the next field in the bitstream. This fieldshould be set to 0 in the second field’s header data.Quantization table offsetThe offset, in bytes, from the start of the field data to the quantization table. If this field is set to 0, checkthe image description for a default quantization table.Huffman table offsetThe offset, in bytes, from the start of the field data to the Huffman table. If this field is set to 0, check theimage description for a default Huffman table.Start of frame offsetThe offset from the start of the field data to the field’s image data. This field should never be set to 0.Start of scan offsetThe offset, in bytes, from the start of the field data to the start of scan data.Start of data offsetThe offset, in bytes, from the start of the field data to the start of the data stream. Typically, this immediatelyfollows the start of scan data.Note The last two fields were “reserved, must be set to zero” in the original Motion-JPEG specification.The Motion-JPEG format B header must be a multiple of 16 in size. When you add pad bytes to the header, setthem to 0.Because Motion-JPEG format B does not support markers, the JPEG bitstream does not have NULL bytes (0x00)inserted after data bytes that are set to 0xFF.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.175