gstvideo.video_overlay_composition
Module for [VideoOverlayComposition] class
Types 1
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.
VideoOverlayComposition self()Returns `this`, for use in `with` statements.void addRectangle(gstvideo.video_overlay_rectangle.VideoOverlayRectangle rectangle)Adds an overlay rectangle to an existing overlay composition object. This must be done right after creating the overlay composition.bool blend(gstvideo.video_frame.VideoFrame videoBuf)Blends the overlay rectangles in comp on top of the raw video data contained in videobuf. The data in videobuf must be writable and mapped appropriately.gstvideo.video_overlay_composition.VideoOverlayComposition copy()Makes a copy of comp 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 ren...gstvideo.video_overlay_rectangle.VideoOverlayRectangle getRectangle(uint n)Returns the `n`-th #GstVideoOverlayRectangle contained in comp.uint 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 s...gstvideo.video_overlay_composition.VideoOverlayComposition makeWritable()Takes ownership of comp and returns a version of comp that is writable (i.e. can be modified). Will either return comp right away, or create a new writable copy of comp and unref comp itself. All t...uint nRectangles()Returns the number of #GstVideoOverlayRectangle<!-- -->s contained in comp. Returns: the number of rectanglesthis(gstvideo.video_overlay_rectangle.VideoOverlayRectangle rectangle = null)Creates a new video overlay composition object to hold one or more overlay rectangles.