Class Pipeline

java.lang.Object
org.javagi.base.ProxyInstance
org.gnome.gobject.TypeInstance
org.gnome.gobject.GObject
org.gnome.gobject.InitiallyUnowned
org.freedesktop.gstreamer.gst.GstObject
org.freedesktop.gstreamer.gst.Element
org.freedesktop.gstreamer.gst.Bin
org.freedesktop.gstreamer.gst.Pipeline
All Implemented Interfaces:
ChildProxy, Proxy
@Generated("org.javagi.JavaGI") public class Pipeline extends Bin implements ChildProxy

A GstPipeline is a special GstBin used as the toplevel container for the filter graph. The GstPipeline will manage the selection and distribution of a global GstClock as well as provide a GstBus to the application.

gst_pipeline_new() is used to create a pipeline. when you are done with the pipeline, use gst_object_unref() to free its resources including all added GstElement objects (if not otherwise referenced).

Elements are added and removed from the pipeline using the GstBin methods like gst_bin_add() and gst_bin_remove() (see GstBin).

Before changing the state of the GstPipeline (see GstElement) a GstBus should be retrieved with gst_pipeline_get_bus(). This GstBus should then be used to receive GstMessage from the elements in the pipeline. Listening to the GstBus is necessary for retrieving error messages from the GstPipeline and otherwise the GstPipeline might stop without any indication, why. Furthermore, the GstPipeline posts messages even if nobody listens on the GstBus, which will pile up and use up memory.

By default, a GstPipeline will automatically flush the pending GstBus messages when going to the NULL state to ensure that no circular references exist when no messages are read from the GstBus. This behaviour can be changed with gst_pipeline_set_auto_flush_bus().

When the GstPipeline performs the PAUSED to PLAYING state change it will select a clock for the elements. The clock selection algorithm will by default select a clock provided by an element that is most upstream (closest to the source). For live pipelines (ones that return GST_STATE_CHANGE_NO_PREROLL from the gst_element_set_state() call) this will select the clock provided by the live source. For normal pipelines this will select a clock provided by the sinks (most likely the audio sink). If no element provides a clock, a default GstSystemClock is used.

The clock selection can be controlled with the gst_pipeline_use_clock() method, which will enforce a given clock on the pipeline. With gst_pipeline_auto_clock() the default clock selection algorithm can be restored.

A GstPipeline maintains a running time for the elements. The running time is defined as the difference between the current clock time and the base time. When the pipeline goes to READY or a flushing seek is performed on it, the running time is reset to 0. When the pipeline is set from PLAYING to PAUSED, the current clock time is sampled and used to configure the base time for the elements when the pipeline is set to PLAYING again. The effect is that the running time (as the difference between the clock time and the base time) will count how much time was spent in the PLAYING state. This default behaviour can be changed with the gst_element_set_start_time() method.

  • Constructor Details

    • Pipeline

      public Pipeline(MemorySegment address)
      Create a Pipeline instance for the provided memory address.
      Parameters:
      address - the memory address of the native object

    • Pipeline

      public Pipeline(@Nullable String name)
      Create a new pipeline with the given name.
      Parameters:
      name - name of new pipeline

    • Pipeline

      public Pipeline()
      Create a new Pipeline.

  • Method Details

    • getType

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

    • getMemoryLayout

      public static MemoryLayout getMemoryLayout()
      The memory layout of the native struct.
      Returns:
      the memory layout

    • asParent

      protected Pipeline asParent()
      Return this instance as if it were its parent type. Comparable to the Java super keyword, but ensures the parent typeclass is also used in native code.
      Overrides:
      asParent in class Bin
      Returns:
      the instance as if it were its parent type

    • autoClock

      public void autoClock()

      Let this Pipeline select a clock automatically. This is the default behaviour.

      Use this function if you previous forced a fixed clock with gst_pipeline_use_clock() and want to restore the default pipeline clock selection algorithm.

      MT safe.

    • getAutoFlushBus

      public boolean getAutoFlushBus()
      Check if this Pipeline will automatically flush messages when going to the NULL state.
      Returns:

      whether the pipeline will automatically flush its bus when going from READY to NULL state or not.

      MT safe.

    • getBus

      public Bus getBus()
      Gets the GstBus of pipeline. The bus allows applications to receive GstMessage packets.
      Overrides:
      getBus in class Element
      Returns:

      a GstBus, unref after usage.

      MT safe.

    • getClock

      public Clock getClock()

      Gets the current clock used by pipeline. Users of object oriented languages should use gst_pipeline_get_pipeline_clock() to avoid confusion with gst_element_get_clock() which has a different behavior.

      Unlike gst_element_get_clock(), this function will always return a clock, even if the pipeline is not in the PLAYING state.

      Overrides:
      getClock in class Element
      Returns:
      a GstClock, unref after usage.

    • getConfiguredLatency

      public ClockTime getConfiguredLatency()
      Return the configured latency on pipeline.
      Returns:

      this Pipeline configured latency, or GST_CLOCK_TIME_NONE if none has been configured because this Pipeline did not reach the PLAYING state yet.

      MT safe.

      Since:
      1.24

    • getDelay

      public ClockTime getDelay()
      Get the configured delay (see gst_pipeline_set_delay()).
      Returns:

      The configured delay.

      MT safe.

    • getLatency

      public ClockTime getLatency()
      Gets the latency that should be configured on the pipeline. See gst_pipeline_set_latency().
      Returns:
      Latency to configure on the pipeline or GST_CLOCK_TIME_NONE
      Since:
      1.6

    • getPipelineClock

      public Clock getPipelineClock()

      Gets the current clock used by pipeline.

      Unlike gst_element_get_clock(), this function will always return a clock, even if the pipeline is not in the PLAYING state.

      Returns:
      a GstClock, unref after usage.
      Since:
      1.6

    • isLive

      public boolean isLive()
      Check if this Pipeline is live.
      Returns:

      true if this Pipeline is live, false if not or if it did not reach the PAUSED state yet.

      MT safe.

      Since:
      1.24

    • setAutoFlushBus

      public void setAutoFlushBus(boolean autoFlush)

      Usually, when a pipeline goes from READY to NULL state, it automatically flushes all pending messages on the bus, which is done for refcounting purposes, to break circular references.

      This means that applications that update state using (async) bus messages (e.g. do certain things when a pipeline goes from PAUSED to READY) might not get to see messages when the pipeline is shut down, because they might be flushed before they can be dispatched in the main thread. This behaviour can be disabled using this function.

      It is important that all messages on the bus are handled when the automatic flushing is disabled else memory leaks will be introduced.

      MT safe.

      Parameters:
      autoFlush - whether or not to automatically flush the bus when the pipeline goes from READY to NULL state

    • setClock

      public boolean setClock(@Nullable Clock clock)
      Set the clock for pipeline. The clock will be distributed to all the elements managed by the pipeline.
      Overrides:
      setClock in class Element
      Parameters:
      clock - the clock to set
      Returns:

      true if the clock could be set on the pipeline. false if some element did not accept the clock.

      MT safe.

    • setDelay

      public void setDelay(ClockTime delay)

      Set the expected delay needed for all elements to perform the PAUSED to PLAYING state change. delay will be added to the base time of the elements so that they wait an additional delay amount of time before starting to process buffers and cannot be GST_CLOCK_TIME_NONE.

      This option is used for tuning purposes and should normally not be used.

      MT safe.

      Parameters:
      delay - the delay

    • setLatency

      public void setLatency(ClockTime latency)

      Sets the latency that should be configured on the pipeline. Setting GST_CLOCK_TIME_NONE will restore the default behaviour of using the minimum latency from the LATENCY query. Setting this is usually not required and the pipeline will figure out an appropriate latency automatically.

      Setting a too low latency, especially lower than the minimum latency from the LATENCY query, will most likely cause the pipeline to fail.

      Parameters:
      latency - latency to configure
      Since:
      1.6

    • useClock

      public void useClock(@Nullable Clock clock)

      Force this Pipeline to use the given clock. The pipeline will always use the given clock even if new clock providers are added to this pipeline.

      If clock is null all clocking will be disabled which will make the pipeline run as fast as possible.

      MT safe.

      Parameters:
      clock - the clock to use

    • builder

      public static Pipeline.Builder<? extends Pipeline.Builder> builder()
      A Pipeline.Builder object constructs a Pipeline with the specified properties. Use the various set...() methods to set properties, and finish construction with Pipeline.Builder.build().
      Returns:
      the builder object