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.TH BLIND-CROP 1 blind
.SH NAME
blind-crop - Extract subframes for all frames
.SH SYNOPSIS
.B blind-crop
[-s | -S | -t]
.I width
.I height
.I left
.I top
.SH DESCRIPTION
.B blind-crop
reads a video from stdin and prints a cropped
version of the video to stdout. The new video
with have the specified
.I width
and
.IR height ,
and will have the same length as the input video.
The left-most pixels of the subvideo will be
.I left
pixels rightward of the left-most pixels of the
input video. The top-most pixels of the subvideo
will be
.I top
pixels downward of the top-most pixels of the
input video.
.P
The selected subvideo may not extend beyond the
input video.
.SH OPTIONS
.TP
.B -s
Instead of resizing the video, set alpha (and
all colour parameters) to 0 on each pixel outside
the selected region.
.TP
.B -S
Instead of resizing the video, set alpha (and
all colour parameters) to 0 on each pixel inside
the selected region.
.TP
.B -t
Instead of changing the width and height of
the output video, put the subvideo side-by-side.
The subvideo's left-most pixel will be positioned
.I left
pixels rightward of the output video's left-most pixel,
and the subvideo's top-most pixel will be positioned
.I top
pixels downward of the output video's left-most pixel.
.SH REQUIREMENTS
.B blind-crop
requires enough free memory to load two full frames into
memory, one of the size of the source video's frames,
and one of the size of the target video's frames. However,
if
.B -s
or
.B -S
is used, only memory for one full frame, of the size of
the source video's frames, are required. A frame requires
32 bytes per pixel it contains.
.B blind-crop
has not been optimised for memory usage, but instead
for code simplicity.
.SH SEE ALSO
.BR blind (7),
.BR blind-extend (1),
.BR blind-translate (1)
.SH AUTHORS
Mattias Andrée
.RI < maandree@kth.se >
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