GStreamer Plugin Writer's Guide (0.8.3.2) | ||
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Sometimes object properties are not powerful enough to control the parameters that affect the behaviour of your element. When this is the case you can expose these parameters as Dynamic Parameters which can be manipulated by any Dynamic Parameters aware application.
Throughout this section, the term dparams will be used as an abbreviation for "Dynamic Parameters".
Your first exposure to dparams may be to convert an existing element from using object properties to using dparams. The following table gives an overview of the difference between these approaches. The significance of these differences should become apparent later on.
Object Properties | Dynamic Parameters | |
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Parameter definition | Class level at compile time | Any level at run time |
Getting and setting | Implemented by element subclass as functions | Handled entirely by dparams subsystem |
Extra objects required | None - all functionality is derived from base GObject | Element needs to create and store a GstDParamManager at object creation |
Frequency and resolution of updates | Object properties will only be updated between calls to _get, _chain or _loop | dparams can be updated at any rate independant of calls to _get, _chain or _loop up to sample-level accuracy |
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