Enum Class StateChange

java.lang.Object
java.lang.Enum<StateChange>
org.freedesktop.gstreamer.gst.StateChange
All Implemented Interfaces:
Serializable, Comparable<StateChange>, Constable, Enumeration
@Generated("org.javagi.JavaGI") public enum StateChange extends Enum<StateChange> implements Enumeration
These are the different state changes an element goes through. State.NULL ⇒ State.PLAYING is called an upwards state change and State.PLAYING ⇒ State.NULL a downwards state change.

  • Enum Constant Details

    • NULL_TO_READY

      public static final StateChange NULL_TO_READY

      state change from NULL to READY.

      • The element must check if the resources it needs are available. Device sinks and -sources typically try to probe the device to constrain their caps.
      • The element opens the device (in case feature need to be probed).

    • READY_TO_PAUSED

      public static final StateChange READY_TO_PAUSED

      state change from READY to PAUSED.

      • The element pads are activated in order to receive data in PAUSED. Streaming threads are started.
      • Some elements might need to return StateChangeReturn.ASYNC and complete the state change when they have enough information. It is a requirement for sinks to return StateChangeReturn.ASYNC and complete the state change when they receive the first buffer or EventType.EOS (preroll). Sinks also block the dataflow when in PAUSED.
      • A pipeline resets the running_time to 0.
      • Live sources return StateChangeReturn.NO_PREROLL and don't generate data.

    • PAUSED_TO_PLAYING

      public static final StateChange PAUSED_TO_PLAYING

      state change from PAUSED to PLAYING.

      • Most elements ignore this state change.
      • The pipeline selects a GstClock and distributes this to all the children before setting them to PLAYING. This means that it is only allowed to synchronize on the GstClock in the PLAYING state.
      • The pipeline uses the GstClock and the running_time to calculate the base_time. The base_time is distributed to all children when performing the state change.
      • Sink elements stop blocking on the preroll buffer or event and start rendering the data.
      • Sinks can post MessageType.EOS in the PLAYING state. It is not allowed to post MessageType.EOS when not in the PLAYING state.
      • While streaming in PAUSED or PLAYING elements can create and remove sometimes pads.
      • Live sources start generating data and return StateChangeReturn.SUCCESS.

    • PLAYING_TO_PAUSED

      public static final StateChange PLAYING_TO_PAUSED

      state change from PLAYING to PAUSED.

      • Most elements ignore this state change.
      • The pipeline calculates the running_time based on the last selected GstClock and the base_time. It stores this information to continue playback when going back to the PLAYING state.
      • Sinks unblock any GstClock wait calls.
      • When a sink does not have a pending buffer to play, it returns GST_STATE_CHANGE_ASYNC from this state change and completes the state change when it receives a new buffer or an EventType.EOS.
      • Any queued MessageType.EOS items are removed since they will be reposted when going back to the PLAYING state. The EOS messages are queued in GstBin containers.
      • Live sources stop generating data and return StateChangeReturn.NO_PREROLL.

    • PAUSED_TO_READY

      public static final StateChange PAUSED_TO_READY

      state change from PAUSED to READY.

      • Sinks unblock any waits in the preroll.
      • Elements unblock any waits on devices
      • Chain or get_range functions return FlowReturn.FLUSHING.
      • The element pads are deactivated so that streaming becomes impossible and all streaming threads are stopped.
      • The sink forgets all negotiated formats
      • Elements remove all sometimes pads

    • READY_TO_NULL

      public static final StateChange READY_TO_NULL

      state change from READY to NULL.

      • Elements close devices
      • Elements reset any internal state.

    • NULL_TO_NULL

      public static final StateChange NULL_TO_NULL
      state change from NULL to NULL. (Since: 1.14)

    • READY_TO_READY

      public static final StateChange READY_TO_READY
      state change from READY to READY, This might happen when going to PAUSED asynchronously failed, in that case elements should make sure they are in a proper, coherent READY state. (Since: 1.14)

    • PAUSED_TO_PAUSED

      public static final StateChange PAUSED_TO_PAUSED
      state change from PAUSED to PAUSED. This might happen when elements were in PLAYING state and 'lost state', they should make sure to go back to real 'PAUSED' state (prerolling for example). (Since: 1.14)

    • PLAYING_TO_PLAYING

      public static final StateChange PLAYING_TO_PLAYING
      state change from PLAYING to PLAYING. (Since: 1.14)

  • Method Details

    • values

      public static StateChange[] values()
      Returns an array containing the constants of this enum class, in the order they are declared.
      Returns:
      an array containing the constants of this enum class, in the order they are declared

    • valueOf

      public static StateChange valueOf(String name)
      Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)
      Parameters:
      name - the name of the enum constant to be returned.
      Returns:
      the enum constant with the specified name
      Throws:
      IllegalArgumentException - if this enum class has no constant with the specified name
      NullPointerException - if the argument is null

    • of

      public static StateChange of(int value)
      Create a new StateChange for the provided value
      Parameters:
      value - the enum value
      Returns:
      the enum for the provided value

    • getValue

      public int getValue()
      Get the numeric value of this enum
      Specified by:
      getValue in interface Enumeration
      Returns:
      the enum value

    • of

      public static StateChange of(MemorySegment address)
      Create a new StateChange for the value in the provided memory address.
      Parameters:
      address - the memory address holding a enum value
      Returns:
      the enum for the value in the provided memory address

    • getType

      public static @Nullable Type getType()
      Get the GType of the StateChange class.
      Returns:
      the GType

    • getName

      public String getName()
      Gets a string representing the given state transition.
      Returns:
      a string with the name of the state result.
      Since:
      1.14