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

Media Data Atom TypesVideo MediaTable 4-6Index0123–5678–65535Table of matrix index and valuesVideo StandardReservedRecommendation ITU-R BT.709-2 (1125/60/2:1 only), SMPTE 274M-1995, 296M-1997 Seebelow for matrix values.Coefficient values are unknownReservedRecommendation ITU-R BT.601-4 and BT.470-4 System B and G, SMPTE 170M-1994,293M-1996 See below for matrix valuesSMPTE 240M-1995, 274M-1995 See below for matrix valuesReservedFigure 4-8 Matrix values for index code 1Figure 4-9 Matrix values for index code 6Figure 4-10 Matrix values for index code 7Clean Aperture ('clap')The clean aperture extension defines the relationship between the pixels in a stored image and a canonicalrectangular region of a video system from which it was captured or to which it will be displayed. This can beused to correlate pixel locations in two or more images—possibly recorded using different systems—foraccurate compositing. This is necessary because different video digitizer devices can digitize different regionsof the incoming video signal, causing pixel misalignment between images. In particular, a stored image maycontain “edge” data outside the canonical display area for a given system.The clean aperture is either coincident with the stored image or a subset of the stored image; if it is a subset,it may be centered on the stored image, or it may be offset positively or negatively from the stored imagecenter.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.167