Universal features
Features that you include in any file that includes a profile atom.
Overview
A feature consists of four fields: a reserved field, which is set to zero; a part-ID, which specifies which brand the feature belongs to; a feature code, which identifies the feature; and a value field, which holds the feature value).
The part-ID can be either universal or brand-specific. Universal features have a part-ID of four ASCII spaces (0x20202020). Brand-specific features have a part-ID for a particular brand, which is taken from the Compatible_brands field of the file type atom. Brand-specific features of QuickTime files have a part-ID of 'qt '. All features listed in this section are universal features; that is, they can be used in any file that includes a profile atom.
It is permissible to use the feature code of 0x00000000 as a placeholder, paired with a feature value of 0x00000000 for one or more features. Readers should simply ignore features having a feature code of zero.
No feature will exist to describe the unit of other features, such as bit rate. The device should consider the magnitude and tailor its display appropriately.
This specification describes only how features are stored in files. It does not require that the values of features be reported (for example, in a user interface) in the same manner as they are stored, or require that they be reported at all.
Topics
Setting features
Table of featuresMaximum video bit rateAverage video bit rateMaximum audio bit rateAverage audio bit rateQuickTime video codec typeQuickTime audio codec typeMPEG-4 video profileMPEG-4 video codecMPEG-4 video object typeMPEG-4 audio codecMaximum video size in a movieMaximum video size in a trackMaximum video frame rate in a single trackAverage video frame rate in a single trackVideo variable frame rate indicationAudio sample rate for a sample entryAudio variable bit rate indicationAudio channel count