Subtract - Revision history

Raffriff42: add link

2016-02-27T14:33:56Z

add link

Raffriff42: one more touch-up

2016-02-14T04:50:11Z

one more touch-up

Raffriff42: formatting, links, phrasing

2016-02-14T04:48:16Z

formatting, links, phrasing

Raffriff42: added category

2015-11-08T14:52:19Z

added category

Raffriff42: added category:Debugging/Diagnostic_filters

2015-06-03T22:11:03Z

added category:Debugging/Diagnostic_filters

Admin: 1 revision

2013-05-09T15:02:27Z

1 revision

Wilbert: synced with offline docs

2007-02-24T23:10:53Z

synced with offline docs

New page

{{Template:FuncDef|Subtract(clip1 ''clip'', clip2 ''clip'')}}

Subtract produces an output clip in which every pixel is set according to the difference between the corresponding pixels in clip1 and clip2. More specifically, it sets each pixel to (50% grey) + (clip1 pixel) - (clip2 pixel). You can use [[Levels]] afterwards if you want to increase the contrast.

'''Examples:'''

# make the differences between clip1 and clip2 blatantly obvious:
Subtract(clip1, clip2).Levels(127, 1, 129, 0, 255)

If you want to see the deltas between adjacent frames in a single clip, you can do it like this:

Subtract(clip.Trim(1, 0), clip)

'''About offset of luma range:'''

For YUV formats the valid Y range is from 16 to 235 inclusive and subtract takes this into account. This means that the following script

Subtract(any_clip, any_clip)

will result in a grey clip with luma = 126. For those that require a subtract function for pc_range YUV data use [[Overlay]]:

# Overlay(any_clip, any_clip, mode="difference", pc_range=true) # grey clip with luma = 128
Overlay(clip1, clip2, mode="difference", pc_range=true)

[[Category:Internal filters]]

← Older revision		Revision as of 14:33, 27 February 2016
Line 1:		Line 1:
−	Show the difference between two clips. Where the clips are equal, the output is 50% grey.	+	Show the difference between two clips. Where the clips are equal, the output is 50% grey.<br>
		+	See [[filters with multiple input clips]] for the resulting [[Clip_properties\|clip properties]].

	==== Syntax ====		==== Syntax ====

@@ Line 1: / Line 1: @@
 Show the difference between two clips. Where the clips are equal, the output is 50% grey.
-== Syntax ==
+==== Syntax ====
 {{Template:FuncDef|Subtract(clip ''clip1'', clip ''clip2'')}}

← Older revision		Revision as of 14:52, 8 November 2015
Line 26:		Line 26:
	[[Category:Internal filters]]		[[Category:Internal filters]]
	[[Category:Debugging/Diagnostic_filters]]		[[Category:Debugging/Diagnostic_filters]]
		+	[[Category:Layering]]

← Older revision		Revision as of 22:11, 3 June 2015
Line 25:		Line 25:

	[[Category:Internal filters]]		[[Category:Internal filters]]
		+	[[Category:Debugging/Diagnostic_filters]]

@@ Line 1: / Line 1: @@
-{{Template:FuncDef|Subtract(clip1 ''clip'', clip2 ''clip'')}}
+Show the difference between two clips. Where the clips are equal, the output is 50% grey.
-Subtract produces an output clip in which every pixel is set according to the difference between the corresponding pixels in clip1 and clip2. More specifically, it sets each pixel to (50% grey) + (clip1 pixel) - (clip2 pixel). You can use [[Levels]] afterwards if you want to increase the contrast.
+== Syntax ==
-'''Examples:'''
+==== Examples ====
- # make the differences between clip1 and clip2 blatantly obvious:
+Show the difference between adjacent frames:
-  Subtract(clip1, clip2).Levels(127, 1, 129, 0, 255)
+<div {{BoxWidthIndent|46|2}} >
-If you want to see the deltas between adjacent frames in a single clip, you can do it like this:
+==== About offset of luma range ====
-  Subtract(clip.Trim(1, 0), clip)
+For YUV formats the valid ''Y'' range is 16-235, and '''Subtract''' takes this into account. This means that the following script
-'''About offset of luma range:'''
+If you require a mathematically correct ''subtract'' function for 0-255 RGB or YUV data, use [[Overlay]]:
+<div {{BoxWidthIndent|46|2}} >
-For YUV formats the valid Y range is from 16 to 235 inclusive and subtract takes this into account. This means that the following script
+  Overlay(A, B, mode="difference", pc_range=false)
+</div>
- Subtract(any_clip, any_clip)
+...which results in a "50% grey" clip with luma=128.
-−
-will result in a grey clip with luma = 126. For those that require a subtract function for pc_range YUV data use [[Overlay]]:
-−
-  # Overlay(any_clip, any_clip, mode="difference", pc_range=true) # grey clip with luma = 128
- Overlay(clip1, clip2, mode="difference", pc_range=true)