Feature entries
A list of feature entries.
Overview
Each feature entry consists of:
reservedA 32-bit field that must be set to zero.
part-IDEither a brand identifier that occurs in the file-type atom of the same file, indicating a feature that is specific to this brand, or the value
0x20202020(four ASCII spaces) indicating a universal feature that can be found in any file type that allows the profile atom. The value 0 is reserved for an empty slot.feature-codeA four-character code either documented here (universal features), or in the specification identified by the brand. The value of
0is reserved for an empty slot with no meaningful feature-value.feature-valueEither a value from an enumerated set (for example,
1or0fortrueorfalse, or an MPEG-4 profile-level ID) or a value that can compared (for example, bit rate as an integer or dimensions as a 32-bit packed structure).
The following table shows the layout of a typical feature.
Data field | Bytes |
|---|---|
Reserved = | 4 |
Part ID = ’ ’ ( | 4 |
Feature code = | 4 |
Value = | 4 |