URI: 
       blind-set-alpha.1 - blind - suckless command-line video editing utility
  HTML git clone git://git.suckless.org/blind
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       blind-set-alpha.1 (1064B)
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            1 .TH BLIND-SET-ALPHA 1 blind
            2 .SH NAME
            3 blind-set-alpha - Multiply the alpha channel of a video
            4 .SH SYNOPSIS
            5 .B blind-set-alpha
            6 [-i]
            7 .I alpha-stream
            8 .SH DESCRIPTION
            9 .B blind-set-alpha
           10 reads a video from stdin and a mask video from
           11 .IR alpha-stream .
           12 The video is printed to stdout, with each alpha value
           13 multiplied by the product of the luminosity and the
           14 alpha value of the corresponding pixel and frame in
           15 the mask video.
           16 .P
           17 If stdin is longer than
           18 .IR alpha-stream ,
           19 the remainder of stdin is printed without any changes.
           20 If stdin is shorter than
           21 .IR alpha-stream ,
           22 the remainder of
           23 .I alpha-stream
           24 is ignored but may be partially read.
           25 .SH OPTIONS
           26 .TP
           27 .B -i
           28 Use the inverse luminosity of the mask video instead
           29 of the luminosity. It is still multiplied by the
           30 alpha value.
           31 .SH SEE ALSO
           32 .BR blind (7),
           33 .BR blind-single-colour (1),
           34 .BR blind-dissolve (1),
           35 .BR blind-transition (1),
           36 .BR blind-arithm (1),
           37 .BR blind-set-luma (1),
           38 .BR blind-invert-luma (1),
           39 .BR blind-set-saturation (1),
           40 .BR blind-extract-alpha (1)
           41 .SH AUTHORS
           42 Mattias Andrée
           43 .RI < maandree@kth.se >