.. _net.sf.cimg.CImgChromaBlur:

ChromaBlur node
===============

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*This documentation is for version 4.0 of ChromaBlur.*

Description
-----------

Blur the chrominance of an input stream. Smoothing is done on the x and y components in the CIE xyY color space. Used to prep strongly compressed and chroma subsampled footage for keying.

The blur filter can be a quasi-Gaussian, a Gaussian, a box, a triangle or a quadratic filter.

Uses the ‘vanvliet’ and ‘deriche’ functions from the CImg library.

CImg is a free, open-source library distributed under the CeCILL-C (close to the GNU LGPL) or CeCILL (compatible with the GNU GPL) licenses. It can be used in commercial applications (see http://cimg.eu).

Inputs
------

+--------+-------------+----------+
| Input  | Description | Optional |
+========+=============+==========+
| Source |             | No       |
+--------+-------------+----------+
| Mask   |             | Yes      |
+--------+-------------+----------+

Controls
--------

.. tabularcolumns:: |>{\raggedright}p{0.2\columnwidth}|>{\raggedright}p{0.06\columnwidth}|>{\raggedright}p{0.07\columnwidth}|p{0.63\columnwidth}|

.. cssclass:: longtable

+------------------------------+---------+-----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Parameter / script name      | Type    | Default   | Function                                                                                                                                                                           |
+==============================+=========+===========+====================================================================================================================================================================================+
| Size / ``size``              | Double  | x: 0 y: 0 | Size (diameter) of the filter kernel, in pixel units (>=0). The standard deviation of the corresponding Gaussian is size/2.4. No filter is applied if size < 1.2.                  |
+------------------------------+---------+-----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Uniform / ``uniform``        | Boolean | Off       | Apply the same amount of blur on X and Y.                                                                                                                                          |
+------------------------------+---------+-----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Colorspace / ``colorspace``  | Choice  | Rec. 709  | | Formula used to compute chrominance from RGB values.                                                                                                                             |
|                              |         |           | | **Rec. 709 (rec709)**: Use Rec. 709 with D65 illuminant.                                                                                                                         |
|                              |         |           | | **Rec. 2020 (rec2020)**: Use Rec. 2020 with D65 illuminant.                                                                                                                      |
|                              |         |           | | **ACES AP0 (acesap0)**: Use ACES AP0 with ACES (approx. D60) illuminant.                                                                                                         |
|                              |         |           | | **ACES AP1 (acesap1)**: Use ACES AP1 with ACES (approx. D60) illuminant.                                                                                                         |
+------------------------------+---------+-----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Filter / ``filter``          | Choice  | Gaussian  | | Bluring filter. The quasi-Gaussian filter should be appropriate in most cases. The Gaussian filter is more isotropic (its impulse response has rotational symmetry), but slower. |
|                              |         |           | | **Quasi-Gaussian (quasigaussian)**: Quasi-Gaussian filter (0-order recursive Deriche filter, faster) - IIR (infinite support / impulsional response).                            |
|                              |         |           | | **Gaussian (gaussian)**: Gaussian filter (Van Vliet recursive Gaussian filter, more isotropic, slower) - IIR (infinite support / impulsional response).                          |
|                              |         |           | | **Box (box)**: Box filter - FIR (finite support / impulsional response).                                                                                                         |
|                              |         |           | | **Triangle (triangle)**: Triangle/tent filter - FIR (finite support / impulsional response).                                                                                     |
|                              |         |           | | **Quadratic (quadratic)**: Quadratic filter - FIR (finite support / impulsional response).                                                                                       |
+------------------------------+---------+-----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| (Un)premult / ``premult``    | Boolean | Off       | Divide the image by the alpha channel before processing, and re-multiply it afterwards. Use if the input images are premultiplied.                                                 |
+------------------------------+---------+-----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Invert Mask / ``maskInvert`` | Boolean | Off       | When checked, the effect is fully applied where the mask is 0.                                                                                                                     |
+------------------------------+---------+-----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Mix / ``mix``                | Double  | 1         | Mix factor between the original and the transformed image.                                                                                                                         |
+------------------------------+---------+-----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

.. |pluginIcon| image:: net.sf.cimg.CImgChromaBlur.png
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