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 ccaa9d50 ("media: vivid: drop overlay support")
Signed-off-by: Dorcas Anono Litunya <anonolitunya@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

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
 --------------