Documentation:Modules/bluescreen

Module: bluescreen
Type	Video filter
First VLC version	0.9.0
Last VLC version	-
Operating system(s)	all
Description	Change the video's alpha channel
Shortcut(s)	bluescreen

This filter can be used in the mosaic framework to set a video's alpha channel (or transparency) based on a pixel's color. This is also known as green screen or chroma key blending and can be used to create effects like on most weather channels.

Options

• bluescreen-u <integer [0 .. 255]> : U chroma component. default value: 120
• bluescreen-v <integer [0 .. 255]> : V chroma component. default value: 90
• bluescreen-ut <integer [0 .. 255]> : Tolerance of the bluescreen blender on color variations for the U plane. A value between 10 and 20 seems sensible. default value: 17
• bluescreen-vt <integer [0 .. 255]> : Tolerance of the bluescreen blender on color variations for the V plane. A value between 10 and 20 seems sensible. default value: 17

Example

% vlc -vvv --vlm-conf mosaic.vlm --mosaic-keep-picture --sub-filter mosaic

And the vlm config:

new channel0 broadcast enabled
setup channel0 input rushfondvert.avi
setup channel0 output #duplicate{dst=mosaic-bridge{chroma=YUVA,vfilter=bluescreen},select=video}
 
new background broadcast enabled
setup background input redefined-nintendo.mpg
control background play
 
control channel0 play

Have a look at people.videolan.org/~dionoea/bluescreen2.mpg (archived) for an example of the VLC bluescreen filter. The overlay video is rushfondvert.avi (archived) and features someone with a mask in front of a green background. The bluescreen module's default values are adjusted to remove the background from this video. For other videos you should use your favorite color editing tool to find out the appropriate U and V values.

Another example

Tested with VLC 2.0.0

new channel0 broadcast enabled
setup channel0 input rushfondvert.avi
setup channel0 output #duplicate{dst=mosaic-bridge{height=270,width=360,chroma=YUVA,vfilter=bluescreen},select=video}:display

new background broadcast enabled
setup background input file:///mire.jpg

control background play
control channel0 play

Source code

• modules/video_filter/bluescreen.c

See also

• YUV

This page is part of official VLC media player Documentation (User Guide • Streaming HowTo • Hacker Guide • Modules)
Please read the Documentation Editing Guidelines before you edit the documentation

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.