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

Media Data Atom TypesCubic PanoramaskQTVRVerticalCylinder ('vcyl'). For compatibility with older QuickTime VR files, when the panoTypefield is nil, then a cylinder is assumed, with the low order bit of the flags field set to 1 to indicate if the cylinderis horizontal and 0 if the cylinder is vertical.One consequence of reorienting the panorama horizontally is that, when the panorama is divided into separatetiles, the order of the samples in the file is now the reverse of what it was for vertical cylinders. Since verticalcylinders were rotated 90 degrees counterclockwise, the first tile added to the image track was the rightmosttile in the panorama. For unrotated horizontal cylinders, the first tile added to the image track is the left-mosttile in the panorama.Cubic PanoramasNote VR Media is deprecated in the QuickTime file format. The information that follows is intendedto document existing content containing VR Media and should not be used for new development.A new type of panorama was introduced in the current version of QuickTime: the cubic panorama. This panoramain its simplest form is represented by six faces of a cube, thus enabling the viewer to see all the way up andall the way down. The file format and the cubic rendering engine actually allow for more complicatedrepresentations, such as special types of cubes with elongated sides or cube faces made up of separate tiles.Atoms that describe the orientation of each face allow for these nonstandard representations. If these atomsare not present, then the simplest representation is assumed. The following describes this simplestrepresentation: a cube with six square sides.Tracks in a cubic movie are laid out as they are for cylindrical panoramas. This includes a QTVR track, a panoramatrack, and an image track. Optionally, there may also be a hot spot track and a fast-start preview track. Theimage, hot spot, and preview tracks are all standard QuickTime video tracks.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.296