wlr export DMA-BUF

a protocol for low overhead screen content capturing

An interface to capture surfaces in an efficient way by exporting DMA-BUFs.

Warning! The protocol described in this file is experimental and backward incompatible changes may be made. Backward compatible changes may be added together with the corresponding interface version bump. Backward incompatible changes are done by bumping the version number in the protocol and interface names and resetting the interface version. Once the protocol is to be declared stable, the 'z' prefix and the version number in the protocol and interface names are removed and the interface version number is reset.

zwlr_export_dmabuf_manager_v1

version 1

manager to inform clients and begin capturing

This object is a manager with which to start capturing from sources.

zwlr_export_dmabuf_manager_v1::capture_output

capture_output(frame: new_id<zwlr_export_dmabuf_frame_v1>, overlay_cursor: int, output: object<wl_output>)

Argument	Type	Description
frame	new_id<zwlr_export_dmabuf_frame_v1>
overlay_cursor	int	include custom client hardware cursor on top of the frame
output	object<wl_output>

capture a frame from an output

Capture the next frame of an entire output.

zwlr_export_dmabuf_manager_v1::destroy

Type: destructor

destroy()

destroy the manager

All objects created by the manager will still remain valid, until their appropriate destroy request has been called.

zwlr_export_dmabuf_frame_v1

version 1

a DMA-BUF frame

This object represents a single DMA-BUF frame.

If the capture is successful, the compositor will first send a "frame" event, followed by one or several "object". When the frame is available for readout, the "ready" event is sent.

If the capture failed, the "cancel" event is sent. This can happen anytime before the "ready" event.

Once either a "ready" or a "cancel" event is received, the client should destroy the frame. Once an "object" event is received, the client is responsible for closing the associated file descriptor.

All frames are read-only and may not be written into or altered.

zwlr_export_dmabuf_frame_v1::destroy

Type: destructor

destroy()

delete this object, used or not

Unreferences the frame. This request must be called as soon as its no longer used.

It can be called at any time by the client. The client will still have to close any FDs it has been given.

zwlr_export_dmabuf_frame_v1::frame

frame(width: uint, height: uint, offset_x: uint, offset_y: uint, buffer_flags: uint, flags: uint<zwlr_export_dmabuf_frame_v1.flags>, format: uint, mod_high: uint, mod_low: uint, num_objects: uint)

Argument	Type	Description
width	uint	frame width in pixels
height	uint	frame height in pixels
offset_x	uint	crop offset for the x axis
offset_y	uint	crop offset for the y axis
buffer_flags	uint	flags which indicate properties (invert, interlacing), has the same values as zwp_linux_buffer_params_v1:flags
flags	uint<zwlr_export_dmabuf_frame_v1.flags>	indicates special frame features
format	uint	format of the frame (DRM_FORMAT_*)
mod_high	uint	drm format modifier, high
mod_low	uint	drm format modifier, low
num_objects	uint	indicates how many objects (FDs) the frame has (max 4)

a frame description

Main event supplying the client with information about the frame. If the capture didn't fail, this event is always emitted first before any other events.

This event is followed by a number of "object" as specified by the "num_objects" argument.

zwlr_export_dmabuf_frame_v1::object

object(index: uint, fd: fd, size: uint, offset: uint, stride: uint, plane_index: uint)

Argument	Type	Description
index	uint	index of the current object
fd	fd	fd of the current object
size	uint	size in bytes for the current object
offset	uint	starting point for the data in the object's fd
stride	uint	line size in bytes
plane_index	uint	index of the plane the data in the object applies to

an object description

Event which serves to supply the client with the file descriptors containing the data for each object.

After receiving this event, the client must always close the file descriptor as soon as they're done with it and even if the frame fails.

zwlr_export_dmabuf_frame_v1::ready

ready(tv_sec_hi: uint, tv_sec_lo: uint, tv_nsec: uint)

Argument	Type	Description
tv_sec_hi	uint	high 32 bits of the seconds part of the timestamp
tv_sec_lo	uint	low 32 bits of the seconds part of the timestamp
tv_nsec	uint	nanoseconds part of the timestamp

indicates frame is available for reading

This event is sent as soon as the frame is presented, indicating it is available for reading. This event includes the time at which presentation happened at.

The timestamp is expressed as tv_sec_hi, tv_sec_lo, tv_nsec triples, each component being an unsigned 32-bit value. Whole seconds are in tv_sec which is a 64-bit value combined from tv_sec_hi and tv_sec_lo, and the additional fractional part in tv_nsec as nanoseconds. Hence, for valid timestamps tv_nsec must be in [0, 999999999]. The seconds part may have an arbitrary offset at start.

After receiving this event, the client should destroy this object.

zwlr_export_dmabuf_frame_v1::cancel

cancel(reason: uint<zwlr_export_dmabuf_frame_v1.cancel_reason>)

Argument	Type	Description
reason	uint<zwlr_export_dmabuf_frame_v1.cancel_reason>	indicates a reason for cancelling this frame capture

indicates the frame is no longer valid

If the capture failed or if the frame is no longer valid after the "frame" event has been emitted, this event will be used to inform the client to scrap the frame.

If the failure is temporary, the client may capture again the same source. If the failure is permanent, any further attempts to capture the same source will fail again.

After receiving this event, the client should destroy this object.

zwlr_export_dmabuf_frame_v1::flags

flags { transient }

Argument	Value	Description
transient	0x1	clients should copy frame before processing

frame flags

Special flags that should be respected by the client.

zwlr_export_dmabuf_frame_v1::cancel_reason

cancel_reason { temporary, permanent, resizing }

Argument	Value	Description
temporary	0	temporary error, source will produce more frames
permanent	1	fatal error, source will not produce frames
resizing	2	temporary error, source will produce more frames

cancel reason

Indicates reason for cancelling the frame.

Compositor Support

	Mutter 46	KWin 6.2	Sway 1.9	COSMIC 1.0.0	Hyprland 0.42.0	niri 0.1.8	Weston 13	Mir 2.18	GameScope 3.15.14	Jay 1.7.0
zwlr_export_dmabuf_manager_v1	x	x	1	x	x	x	x	x	x	x

Copyright

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice (including the next paragraph) shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.