Programming With QuickTime VR

Memory Management

QuickTime VR can require large amounts of memory to store its internal representation of the uncorrected image associated with a panoramic node, which is stored in the back buffer. To provide flexibility when operating with limited amounts of memory, a movie's author can include several different resolutions of an image, in different video tracks in the movie file. By default, QuickTime VR selects the highest resolution image available. When memory is limited, however, QuickTime VR selects the image with the highest resolution that fits into the memory it can allocate for its back buffer.

The QuickTime VR Manager provides functions that you can use to determine what resolutions are available and to get and set the current resolution of a panoramic node. You can also use QuickTime VR Manager functions to override the default behavior for loading data into the back buffer. By default, if enough memory is available, QuickTime VR allocates a back buffer that is large enough to hold the entire uncorrected panoramic image.