blind

suckless command-line video editing utility
git clone git://git.suckless.org/blind
Log | Files | Refs | README | LICENSE

blind-spectrum.1 (2266B)

      1 .TH BLIND-SPECTRUM 1 blind
      2 .SH NAME
      3 blind-spectrum - Transform a gradient into a spectrum
      4 .SH SYNOPSIS
      5 .B blind-spectrum
      6 [-y]
      7 [-z
      8 .IR depth ]
      9 .I spectrum-stream
     10 .SH DESCRIPTION
     11 .B blind-spectrum
     12 reads a video from stdin, transforms it according
     13 to a colour table and prints the resulting video
     14 to stdout. The values of the colours, excluding
     15 the alpha channel, in stdin, are truncated to
     16 fit [0, 1]. The resulting values for each pixel
     17 is used to look up a colour in
     18 .I spectrum-stream
     19 for the same frame, with linear interpolation.
     20 That colour is used as the pixel's colour. The
     21 alpha values of the looked up colour and the
     22 pixel's original colour are multiplied, and the
     23 product is used as the pixel's alpha value.
     24 .P
     25 When looking up colours in
     26 .IR spectrum-stream ,
     27 the value of the first channel (the X channel)
     28 is multiplied by the width of the video in
     29 .I spectrum-stream
     30 less 1,
     31 the product is the column in
     32 .I spectrum-stream
     33 that will be used (using interpolation for
     34 none integer products), and the value of the first
     35 channel (the Y channel) is multiplied by the height
     36 of the video in
     37 .I spectrum-stream
     38 less 1, the product is the row in
     39 .I spectrum-stream
     40 that will be used.
     41 .SH OPTIONS
     42 .TP
     43 .B -y
     44 Rather than using the values of the three
     45 colour channels to look up a colour in a
     46 multidimensional table, the luma is used to
     47 look up a value in a singledimensional table.
     48 Which dimension is used does not matter; the
     49 result is unspecified if the colour table
     50 is multidimensional.
     51 .TP
     52 .BR -z \ \fIdepth\fP
     53 For each frame in stdin,
     54 .I depth
     55 frames are read from
     56 .IR spectrum-stream .
     57 When looking up colours in
     58 .IR spectrum-stream ,
     59 the value of the third channel (the > channel)
     60 is multiplied by
     61 .I depth
     62 less 1, the product is the frame
     63 in this set of
     64 .I depth
     65 frames from
     66 .I spectrum-stream
     67 that will be used.
     68 .SH SEE ALSO
     69 .BR blind (7),
     70 .BR blind-from-text (1),
     71 .BR blind-arithm (1),
     72 .BR blind-double-spectrum (1),
     73 .BR blind-round-wave (1),
     74 .BR blind-sawtooth-wave (1),
     75 .BR blind-sine-wave (1)
     76 .BR blind-sinc-wave (1),
     77 .BR blind-triangular-wave (1),
     78 .BR blind-cone-gradient (1),
     79 .BR blind-linear-gradient (1),
     80 .BR blind-radial-gradient (1),
     81 .BR blind-spiral-gradient (1),
     82 .BR blind-square-gradient (1)
     83 .SH AUTHORS
     84 Mattias Andrée
     85 .RI < maandree@kth.se >