Klasse Context

Alle implementierten Schnittstellen:
PointerInterface

public class Context extends Record
#GstContext is a container object used to store contexts like a device
context, a display server connection and similar concepts that should
be shared between multiple elements.

Applications can set a context on a complete pipeline by using
gst_element_set_context(), which will then be propagated to all
child elements. Elements can handle these in #GstElementClass::set_context
and merge them with the context information they already have.

When an element needs a context it will do the following actions in this
order until one step succeeds:

1. Check if the element already has a context
2. Query downstream with %GST_QUERY_CONTEXT for the context
3. Query upstream with %GST_QUERY_CONTEXT for the context
4. Post a %GST_MESSAGE_NEED_CONTEXT message on the bus with the required
context types and afterwards check if a usable context was set now
5. Create a context by itself and post a %GST_MESSAGE_HAVE_CONTEXT message
on the bus.

Bins will catch %GST_MESSAGE_NEED_CONTEXT messages and will set any previously
known context on the element that asks for it if possible. Otherwise the
application should provide one if it can.

#GstContext can be persistent.
A persistent #GstContext is kept in elements when they reach
%GST_STATE_NULL, non-persistent ones will be removed.
Also, a non-persistent context won't override a previous persistent
context set to an element.

https://gstreamer.freedesktop.org/documentation/gstreamer/gi-index.html

  • Konstruktordetails

    • Context

      public Context(PointerContainer pointer)
    • Context

      public Context(@Nonnull Str context_type, boolean persistent)
      Creates a new context.
      Parameter:
      context_type - Context type
      persistent - Persistent context
    • Context

      public Context(String context_type, boolean persistent)
      Creates a new context.
      Parameter:
      context_type - Context type
      persistent - Persistent context
  • Methodendetails

    • getClassHandler

      public static ClassHandler getClassHandler()
    • getContextType

      public Str getContextType()
      Gets the type of @context.
      Gibt zurück:
      The type of the context.
    • getStructure

      public Structure getStructure()
      Accesses the structure of the context.
      Gibt zurück:
      The structure of the context. The structure is still owned by the context, which means that you should not modify it, free it and that the pointer becomes invalid when you free the context.
    • hasContextType

      public boolean hasContextType(@Nonnull Str context_type)
      Checks if @context has @context_type.
      Parameter:
      context_type - Context type to check.
      Gibt zurück:
      %TRUE if @context has @context_type.
    • hasContextType

      public boolean hasContextType(String context_type)
      Checks if @context has @context_type.
      Parameter:
      context_type - Context type to check.
      Gibt zurück:
      %TRUE if @context has @context_type.
    • isPersistent

      public boolean isPersistent()
      Checks if @context is persistent.
      Gibt zurück:
      %TRUE if the context is persistent.
    • writableStructure

      public Structure writableStructure()
      Gets a writable version of the structure.
      Gibt zurück:
      The structure of the context. The structure is still owned by the context, which means that you should not free it and that the pointer becomes invalid when you free the context. This function checks if @context is writable.
    • getTypeID

      public static long getTypeID()
    • getParentTypeID

      public static long getParentTypeID()
    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()
    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()
    • getInstanceSize

      public static int getInstanceSize()