64e4954619
The conversion script added some comments at the end. They point to the original DocBook files, with will be removed after the manual fixes. So, they'll be pointing to nowere. So, remove those comments. They'll be forever stored at the Kernel tree. So, if someone wants the references, it is just a matter of looking at the backlog. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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1.3 KiB
ReStructuredText
29 lines
1.3 KiB
ReStructuredText
.. -*- coding: utf-8; mode: rst -*-
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************
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Introduction
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************
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Some video capture devices can sample a subsection of a picture and
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shrink or enlarge it to an image of arbitrary size. Next, the devices
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can insert the image into larger one. Some video output devices can crop
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part of an input image, scale it up or down and insert it at an
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arbitrary scan line and horizontal offset into a video signal. We call
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these abilities cropping, scaling and composing.
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On a video *capture* device the source is a video signal, and the
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cropping target determine the area actually sampled. The sink is an
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image stored in a memory buffer. The composing area specifies which part
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of the buffer is actually written to by the hardware.
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On a video *output* device the source is an image in a memory buffer,
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and the cropping target is a part of an image to be shown on a display.
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The sink is the display or the graphics screen. The application may
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select the part of display where the image should be displayed. The size
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and position of such a window is controlled by the compose target.
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Rectangles for all cropping and composing targets are defined even if
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the device does supports neither cropping nor composing. Their size and
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position will be fixed in such a case. If the device does not support
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scaling then the cropping and composing rectangles have the same size.
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