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Compact color space definitions.#169

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HansBusch merged 4 commits into
21.12from
video/colorspace
Dec 7, 2021
Merged

Compact color space definitions.#169
HansBusch merged 4 commits into
21.12from
video/colorspace

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@HansBusch

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The default color space is defined as YCbCr. Any implementations using e.g. RGB need to add a full URL like http://www.onvif.org/ver10/colorspace/RGB to each color definition which bloats the metadata stream.

This proposal allows to define a frame wide default.

Backward compatibility consideration:

  • Without this definition all defaults stay as is.
  • With definition older clients may not understand the default and misinterpret the color value.
    Since color isn't widely used - partly due to prohibit bad encoding this change seems to be acceptable.

@svefredrik

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I think we should mention this attribute in the spec as well somewhere under Color descriptor section

<title>Color descriptor</title>

@sujithhanwha

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The default color space is defined as YCbCr. Any implementations using e.g. RGB need to add a full URL like http://www.onvif.org/ver10/colorspace/RGB to each color definition which bloats the metadata stream.

This proposal allows to define a frame wide default.

Backward compatibility consideration:

  • Without this definition all defaults stay as is.
  • With definition older clients may not understand the default and misinterpret the color value.
    Since color isn't widely used - partly due to prohibit bad encoding this change seems to be acceptable.

Does this mean, individual objects can override this colorspace definition? or it should be same as this ?

…readability without content change.

Add color space column to table and mention that it can be set on frame and object level.
@HansBusch

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I don't think that someone would like to define both, but for maximum backward compatibility I suggest that the object colorspace overrides any frame definition. The idea is that the frame definition just changes the default.

@svefredrik

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Great!
Maybe we should also update this line:
https://github.com/onvif/specs/blob/21.12/wsdl/ver10/schema/common.xsd#L182

@sujithhanwha sujithhanwha left a comment

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Minor typo errors marked.

Comment thread doc/Analytics.xml Outdated
range [0 .. 1]. Color covariance describes the variation of color values around the
representative color value in color space thus representative color denotes a region in
color space.</para>
<para>Nate that the color descriptor does not specify, how color clusters are created.

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Typo error Nate --> Note

Comment thread doc/Analytics.xml Outdated
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="http://www.onvif.org/ver10/colorspace/YCbCr"/>. Alternate color spaces as
defined in <xref linkend="_colorspaces"/> can be defined on frame level and individually
for earch object.</para>

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typo earch--> each

@HansBusch HansBusch merged commit 58db7bf into 21.12 Dec 7, 2021
@HansBusch HansBusch deleted the video/colorspace branch December 7, 2021 08:32
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3 participants