.TH BLIND-DUAL-KEY 1 blind
.SH NAME
blind-dual-key - Apply transparency to a video based on two videos and two key
.SH SYNOPSIS
.B blind-dual-key
.I X
.I Y
.I Z
.I dual-X
.I dual-Y
.I dual-Z
.I dual-stream
.SH DESCRIPTION
.B blind-dual-key
reads a video from stdin and a video
.IR dual-stream .
These two videos should be idential, except
with two different background colours. The
background colour used in the video from
stdin should be specified in the arguments
.IR X ,
.IR Y ,
and
.IR Z ,
using the CIE XYZ colour model. The
background colour used in the video from
.I dual-stream
should be specified in the arguments
.IR dual-X ,
.IR dual-Y ,
and
.IR dual-Z ,
using the CIE XYZ colour model. Using this information,
.B blind-dual-key
reconstruct the alpha channel of the video
and prints the video with its alpha channel to
stdout.
.SH NOTES
.B blind-dual-key
may be changed in the future to use some other colour model,
therefore, it is recommended to also use
.BR blind-colour-ciexyz (1)
if you are specifying the colour in CIE XYZ.
.P
When making a video whose transparancy is recovered with
.BR blind-dual-key ,
select to opposite background colours, for
example black and white or green and magenta.
.SH SEE ALSO
.BR blind (7),
.BR blind-colour-ciexyz (1),
.BR blind-colour-srgb (1),
.BR blind-chroma-key (1),
.BR blind-primary-key (1)
.SH AUTHORS
Mattias Andrée
.RI < maandree@kth.se >