Class VideoOverlayComposition

java.lang.Object
org.javagi.base.ProxyInstance
org.freedesktop.gstreamer.video.VideoOverlayComposition
All Implemented Interfaces:
Proxy
@Generated("org.javagi.JavaGI") public class VideoOverlayComposition extends ProxyInstance

Functions to create and handle overlay compositions on video buffers.

An overlay composition describes one or more overlay rectangles to be blended on top of a video buffer.

This API serves two main purposes:

  • it can be used to attach overlay information (subtitles or logos) to non-raw video buffers such as GL/VAAPI/VDPAU surfaces. The actual blending of the overlay can then be done by e.g. the video sink that processes these non-raw buffers.

  • it can also be used to blend overlay rectangles on top of raw video buffers, thus consolidating blending functionality for raw video in one place.

Together, this allows existing overlay elements to easily handle raw and non-raw video as input in without major changes (once the overlays have been put into a GstVideoOverlayComposition object anyway) - for raw video the overlay can just use the blending function to blend the data on top of the video, and for surface buffers it can just attach them to the buffer and let the sink render the overlays.

  • Constructor Details

    • VideoOverlayComposition

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

    • VideoOverlayComposition

      public VideoOverlayComposition(@Nullable VideoOverlayRectangle rectangle)

      Creates a new video overlay composition object to hold one or more overlay rectangles.

      Note that since 1.20 this allows to pass null for rectangle.

      Parameters:
      rectangle - a GstVideoOverlayRectangle to add to the composition

  • Method Details

    • getType

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

    • getMemoryLayout

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

    • addRectangle

      public void addRectangle(VideoOverlayRectangle rectangle)
      Adds an overlay rectangle to an existing overlay composition object. This must be done right after creating the overlay composition.
      Parameters:
      rectangle - a GstVideoOverlayRectangle to add to the composition

    • blend

      public boolean blend(VideoFrame videoBuf)

      Blends the overlay rectangles in this VideoOverlayComposition on top of the raw video data contained in videoBuf. The data in videoBuf must be writable and mapped appropriately.

      Since videoBuf data is read and will be modified, it ought be mapped with flag GST_MAP_READWRITE.

      Parameters:
      videoBuf - a GstVideoFrame containing raw video data in a supported format. It should be mapped using GST_MAP_READWRITE

    • copy

      public VideoOverlayComposition copy()
      Makes a copy of this VideoOverlayComposition and all contained rectangles, so that it is possible to modify the composition and contained rectangles (e.g. add additional rectangles or change the render co-ordinates or render dimension). The actual overlay pixel data buffers contained in the rectangles are not copied.
      Returns:
      a new GstVideoOverlayComposition equivalent to comp.

    • getRectangle

      public @Nullable VideoOverlayRectangle getRectangle(int n)
      Returns the nTh GstVideoOverlayRectangle contained in comp.
      Parameters:
      n - number of the rectangle to get
      Returns:
      the nTh rectangle, or NULL if n is out of bounds. Will not return a new reference, the caller will need to obtain her own reference using gst_video_overlay_rectangle_ref() if needed.

    • getSeqnum

      public int getSeqnum()
      Returns the sequence number of this composition. Sequence numbers are monotonically increasing and unique for overlay compositions and rectangles (meaning there will never be a rectangle with the same sequence number as a composition).
      Returns:
      the sequence number of this VideoOverlayComposition

    • makeWritable

      public VideoOverlayComposition makeWritable()
      Takes ownership of this VideoOverlayComposition and returns a version of this VideoOverlayComposition that is writable (i.e. can be modified). Will either return this VideoOverlayComposition right away, or create a new writable copy of this VideoOverlayComposition and unref this VideoOverlayComposition itself. All the contained rectangles will also be copied, but the actual overlay pixel data buffers contained in the rectangles are not copied.
      Returns:
      a writable GstVideoOverlayComposition equivalent to comp.

    • nRectangles

      public int nRectangles()
      Returns the number of GstVideoOverlayRectangles contained in comp.
      Returns:
      the number of rectangles