Road Map to QuickTime 3

Data Handler Components

Data handler components read and write movie data to specific devices, such as HFS disk files or computer memory. These are extremely low-level pieces of software, and are normally transparent to applications. Applications use data handler components indirectly, by making calls to the Movie Toolbox or to a sequence grabber component. Applications can call some data handler component functions directly, however, for more complete control of data retrieval and storage.

Apple provides data handler components for most device types. If you need to read or write data to a new or unsupported device type, you may need to create a data handler component. Data handler components were introduced as part of QuickTime 2.0.

You need to read this chapter if you plan to create a data handler component, a media handler, or a sequence grabber component. Sequence grabber components and media handlers need to be able to select and use data handler components. Applications programmers who think they may need to call data handler components directly should read the section " Using Data Handler Components ." The section " About Data Handler Components " may also be of general interest to QuickTime developers.

QuickTime 3.0 Reference describes what data handler components are, what they do, and how they work. Diagrams are included which illustrate their different use during movie playback and movie capture.

• Movie Playback
• Movie Capture
• Processing data
• Identifying Containers With Data References

QuickTime 3.0 Reference describes how to use a data handler component. Developers writing sequence grabber components or media handlers will use the interfaces described in this section. Developers writing data handler components will need to support these interfaces.

• Selecting a Data Handler
• Selecting by Component Type Value
• Interrogating a Data Handler's Capabilities
• Managing Data References
• Retrieving Movie Data
• Storing Movie Data
• Managing the Data Handler

QuickTime 3.0 Reference describes how to create a new data handler component. The component type, subtype, and relevant selector flags are defined.

• General Information

QuickTime 3.0 Reference defines all of the functions that a data handler component may support. Many of these functions are optional, as they are only relevant to certain types of data or devices.

• Selecting a Data Handler
• DataHGetVolumeList
• DataHCanUseDataRef
• DataHGetDeviceIndex
• Working With Data References
• DataHSetDataRef
• DataHGetDataRef
• DataHCompareDataRef
• DataHResolveDataRef
• DataHSetOSFileRef
• DataHGetOSFileRef
• Reading Movie Data
• DataHOpenForRead
• DataHCloseForRead
• DataHGetData
• DataHScheduleData
• DataHFinishData
• DataHGetScheduleAheadTime
• Writing Movie Data
• DataHOpenForWrite
• DataHCloseForWrite
• DataHPutData
• DataHWrite
• DataHSetFileSize
• DataHGetFileSize
• DataHCreateFile
• DataHGetPreferredBlockSize
• DataHGetFreeSpace
• DataHPreextend
• Managing Data Handler Components
• DataHTask
• DataHFlushCache
• DataHFlushData
• DataHPlaybackHints
• Completion Function
• Data handler Completion Function