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author | Dorcas Anono Litunya <anonolitunya@gmail.com> | 2024-06-24 12:52:57 +0300 |
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committer | Hans Verkuil <hverkuil-cisco@xs4all.nl> | 2024-06-28 08:00:29 +0200 |
commit | 0bc9574a7a2cac8cf05d1821081cc701e48e75fc (patch) | |
tree | 71265ce9ff7c3fa00f35ba32e6d0381a876b4f6e /Documentation/admin-guide/media | |
parent | 3883822e17f7237d07da4970e642a50de991a76b (diff) |
media: Documentation: vivid.rst: Remove documentation for Capture Overlay
Modifying documentation to remove 'Capture Overlay section' as
destructive capture overlay support was removed.
See commit ccaa9d50ca73 ("media: vivid: drop overlay support")
Signed-off-by: Dorcas Anono Litunya <anonolitunya@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Diffstat (limited to 'Documentation/admin-guide/media')
-rw-r--r-- | Documentation/admin-guide/media/vivid.rst | 68 |
1 files changed, 0 insertions, 68 deletions
diff --git a/Documentation/admin-guide/media/vivid.rst b/Documentation/admin-guide/media/vivid.rst index 917b57225939..31fb86030249 100644 --- a/Documentation/admin-guide/media/vivid.rst +++ b/Documentation/admin-guide/media/vivid.rst @@ -1282,74 +1282,6 @@ data_offset to be non-zero, so this is a useful feature for testing applications Video output will also honor any data_offset that the application set. -Capture Overlay ---------------- - -Note: capture overlay support is implemented primarily to test the existing -V4L2 capture overlay API. In practice few if any GPUs support such overlays -anymore, and neither are they generally needed anymore since modern hardware -is so much more capable. By setting flag 0x10000 in the node_types module -option the vivid driver will create a simple framebuffer device that can be -used for testing this API. Whether this API should be used for new drivers is -questionable. - -This driver has support for a destructive capture overlay with bitmap clipping -and list clipping (up to 16 rectangles) capabilities. Overlays are not -supported for multiplanar formats. It also honors the struct v4l2_window field -setting: if it is set to FIELD_TOP or FIELD_BOTTOM and the capture setting is -FIELD_ALTERNATE, then only the top or bottom fields will be copied to the overlay. - -The overlay only works if you are also capturing at that same time. This is a -vivid limitation since it copies from a buffer to the overlay instead of -filling the overlay directly. And if you are not capturing, then no buffers -are available to fill. - -In addition, the pixelformat of the capture format and that of the framebuffer -must be the same for the overlay to work. Otherwise VIDIOC_OVERLAY will return -an error. - -In order to really see what it going on you will need to create two vivid -instances: the first with a framebuffer enabled. You configure the capture -overlay of the second instance to use the framebuffer of the first, then -you start capturing in the second instance. For the first instance you setup -the output overlay for the video output, turn on video looping and capture -to see the blended framebuffer overlay that's being written to by the second -instance. This setup would require the following commands: - -.. code-block:: none - - $ sudo modprobe vivid n_devs=2 node_types=0x10101,0x1 - $ v4l2-ctl -d1 --find-fb - /dev/fb1 is the framebuffer associated with base address 0x12800000 - $ sudo v4l2-ctl -d2 --set-fbuf fb=1 - $ v4l2-ctl -d1 --set-fbuf fb=1 - $ v4l2-ctl -d0 --set-fmt-video=pixelformat='AR15' - $ v4l2-ctl -d1 --set-fmt-video-out=pixelformat='AR15' - $ v4l2-ctl -d2 --set-fmt-video=pixelformat='AR15' - $ v4l2-ctl -d0 -i2 - $ v4l2-ctl -d2 -i2 - $ v4l2-ctl -d2 -c horizontal_movement=4 - $ v4l2-ctl -d1 --overlay=1 - $ v4l2-ctl -d0 -c loop_video=1 - $ v4l2-ctl -d2 --stream-mmap --overlay=1 - -And from another console: - -.. code-block:: none - - $ v4l2-ctl -d1 --stream-out-mmap - -And yet another console: - -.. code-block:: none - - $ qv4l2 - -and start streaming. - -As you can see, this is not for the faint of heart... - - Output Overlay -------------- |