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.
a #GstVideoOverlayRectangle to add to the composition
Adds an overlay rectangle to an existing overlay composition object. This must be done right after creating the overlay composition.
a #GstVideoOverlayRectangle to add to the composition
Blends the overlay rectangles in comp on top of the raw video data
contained in video_buf. The data in video_buf must be writable and
mapped appropriately.
Since video_buf data is read and will be modified, it ought be
mapped with flag GST_MAP_READWRITE.
a #GstVideoFrame containing raw video data in a supported format. It should be mapped using GST_MAP_READWRITE
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 render dimension). The
actual overlay pixel data buffers contained in the rectangles are not
copied.
Returns the n-th #GstVideoOverlayRectangle contained in comp.
number of the rectangle to get
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).
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 the contained
rectangles will also be copied, but the actual overlay pixel data buffers
contained in the rectangles are not copied.
Returns the number of #GstVideoOverlayRectangles contained in comp.
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.
a #GstVideoOverlayRectangle to add to the composition
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.