| Copyright | Will Thompson and Iñaki García Etxebarria |
|---|---|
| License | LGPL-2.1 |
| Maintainer | Iñaki García Etxebarria |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
GI.GstVideo.Structs.VideoOverlayComposition
Description
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 VideoOverlayComposition 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.
Synopsis
- newtype VideoOverlayComposition = VideoOverlayComposition (ManagedPtr VideoOverlayComposition)
- videoOverlayCompositionAddRectangle :: (HasCallStack, MonadIO m) => VideoOverlayComposition -> VideoOverlayRectangle -> m ()
- videoOverlayCompositionBlend :: (HasCallStack, MonadIO m) => VideoOverlayComposition -> VideoFrame -> m Bool
- videoOverlayCompositionCopy :: (HasCallStack, MonadIO m) => VideoOverlayComposition -> m VideoOverlayComposition
- videoOverlayCompositionGetRectangle :: (HasCallStack, MonadIO m) => VideoOverlayComposition -> Word32 -> m (Maybe VideoOverlayRectangle)
- videoOverlayCompositionGetSeqnum :: (HasCallStack, MonadIO m) => VideoOverlayComposition -> m Word32
- videoOverlayCompositionMakeWritable :: (HasCallStack, MonadIO m) => VideoOverlayComposition -> m VideoOverlayComposition
- videoOverlayCompositionNRectangles :: (HasCallStack, MonadIO m) => VideoOverlayComposition -> m Word32
- videoOverlayCompositionNew :: (HasCallStack, MonadIO m) => Maybe VideoOverlayRectangle -> m VideoOverlayComposition
Exported types
newtype VideoOverlayComposition Source #
Memory-managed wrapper type.
Constructors
| VideoOverlayComposition (ManagedPtr VideoOverlayComposition) |
Instances
Methods
Click to display all available methods, including inherited ones
addRectangle
videoOverlayCompositionAddRectangle Source #
Arguments
| :: (HasCallStack, MonadIO m) | |
| => VideoOverlayComposition |
|
| -> VideoOverlayRectangle |
|
| -> m () |
Adds an overlay rectangle to an existing overlay composition object. This must be done right after creating the overlay composition.
blend
videoOverlayCompositionBlend Source #
Arguments
| :: (HasCallStack, MonadIO m) | |
| => VideoOverlayComposition |
|
| -> VideoFrame |
|
| -> m Bool |
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.
Since videoBuf data is read and will be modified, it ought be
mapped with flag GST_MAP_READWRITE.
copy
videoOverlayCompositionCopy Source #
Arguments
| :: (HasCallStack, MonadIO m) | |
| => VideoOverlayComposition |
|
| -> m VideoOverlayComposition | Returns: a new |
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.
getRectangle
videoOverlayCompositionGetRectangle Source #
Arguments
| :: (HasCallStack, MonadIO m) | |
| => VideoOverlayComposition |
|
| -> Word32 |
|
| -> m (Maybe VideoOverlayRectangle) | Returns: the |
Returns the n-th VideoOverlayRectangle contained in comp.
getSeqnum
videoOverlayCompositionGetSeqnum Source #
Arguments
| :: (HasCallStack, MonadIO m) | |
| => VideoOverlayComposition |
|
| -> m Word32 | Returns: the sequence number of |
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).
makeWritable
videoOverlayCompositionMakeWritable Source #
Arguments
| :: (HasCallStack, MonadIO m) | |
| => VideoOverlayComposition |
|
| -> m VideoOverlayComposition | Returns: a writable |
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.
nRectangles
videoOverlayCompositionNRectangles Source #
Arguments
| :: (HasCallStack, MonadIO m) | |
| => VideoOverlayComposition |
|
| -> m Word32 | Returns: the number of rectangles |
Returns the number of VideoOverlayRectangles contained in comp.
new
videoOverlayCompositionNew Source #
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Maybe VideoOverlayRectangle |
|
| -> m VideoOverlayComposition | Returns: a new |
Creates a new video overlay composition object to hold one or more overlay rectangles.
Note that since 1.20 this allows to pass Nothing for rectangle.