Effects 

Kdenlive uses MLT for all video/audio effects. Effects in Kdenlive are now built using 
xml files describing the effect and its parameters.

Here is a sample effect file:

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

1  <!DOCTYPE kpartgui>
2  <effect tag="motion_est">
3	<name>Auto Mask</name>
4	<properties id="autotrack_rectangle" tag="autotrack_rectangle" />
5	<parameter type="geometry" name="geometry" default="100,100:100x100">
6		<name>Geometry</name>
7	</parameter>
8	<parameter type="bool" name="debug" default="1">
9		<name>Debug</name>
10	</parameter>
11	<parameter type="bool" name="obscure" default="0">
12		<name>Obscure</name>
13	</parameter>
14 </effect>

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Line 1 is required to have the effect and parameter names added to the translation files
In line 2, the "tag" is the name of the mlt filter
Line 3 is the name of the effect that will appear to the user
Line 4 holds several effect parameters:
	id is an internal kdenlive id, can be anything, but must be unique for each effect
	tag is the "mlt_service" name of the effect
	type defines if the effect is "audio" or "video". If omitted, effect is considered as video

Then, you have the parameter definitions.
The parameter entry has the following attributes:
	type is used by Kdenlive to build the UI for this effect.
		allowed types are: 
		- constant = a number, represented by a slider
		- bool = boolean value, represented as a checkbox
		- color = a color value, represented by a selectable color button
		- list = a combobox listing different strings
		- geometry = 4 different sliders for x, y, width and height values that will end up as x,y:wxh
		- position = a frame number that can be obtained from current cursor position
		- double = a number with keyframes
		- complex = only used in obscure effect, has x, y, width, height and pixellation values

		The integer values can have max, min and default values defined, see effect files in this folder for more examples
	the "name" parameter is the name that will be passed to MLT

The "name" tag gives the parameter name as it will appear to the user

Kdenlive parses the effect folder at each startup, so that if you have an xml file describing a new effect, just copy it in your ~/.kde/share/apps/kdenlive/effects/ folder and restart Kdenlive to enable the new effect