CV(1) CV(1)
14 June 1993
NAME
cv - Color image sequence X viewer
SYNOPSIS
cv -a StartFrame -b EndFrame [-iw ImageWidth] [-ih ImageHeight]
[-BW] [-yg Gamma] [-rg Red_Gamma] [-gg Green_Gamma] [-bg Blue_Gamma]
[-d Dither_Scale] [-nr] [-C] [-SF] Filename
DESCRIPTION
cv is an X viewer of image sequences stored as raster-scanned files.
OPTIONS
-a Specifies the start frame for an image sequence.
-b Specifies the end frame (inclusive) for an image sequence.
-iw Specifies the image width for the luminance component.
-ih Specifies the image height for the luminance component.
-BW Specifies black and white mode. This means that only the
luminance file is loaded. Only the luminance gamma is used -yg
if this mode is chosen.
-yg Specifies luminance (or overall) gamma correction used. This can
be used to increase contrast and compensate for individual screen
luminosity.
-rg Specifies red gamma correction used. This can be used to
compensate for screen color.
-gg Specifies green gamma correction used. This can be used to
compensate for screen color.
-bg Specifies blue gamma correction used. This can be used to
compensate for screen color.
-d Specifies factor to scale (the multiplicative factor) the 2x2
dithering matrix. This may correct some annoying dithering
problems.
-C Use CCIR Recommmendation 601 YCbCr->RGB conversion which has
deeper contrast and colors. The default mode is the JFIF YCbCr-
>RGB conversion.
-FC The color range in YCbCr space has been restricted slightly, FC
brings it to full color range. Can be used in conjunction with
-C.
-nr Do not add uniform random noise less than the dithering matrix
stepsize. This is useful for finely quantized frames.
- 1 - Formatted: October 25, 2025
CV(1) CV(1)
14 June 1993
-SF Single frame mode. This enables just one frame to be loaded in.
This option is useful for PVRG-JPEG decoded files.
EXAMPLES
The YCbCr files are also known as digital YUV files, where U is the
same as Cb and V is the same as Cr. To display a single image of
dimensions 400x300 where the YUV files are in foo.3, foo.8, foo.10,
respectively, the command is
cv -iw 400 -ih 300 foo -SF
The numeric suffix is resolved automatically; the same command would
work for foo.0, foo.1, foo.2, or foo.Y, foo.U, foo.V.
To display an image sequence of dimensions 160x128 where the YUV files
are bar.0.Y, bar.0.U, bar.0.V, bar.1.Y, bar.1.U, bar.1.V, ...,
bar.10.Y, bar.10.U, bar.10.V, with a red gamma correction of 1.5, type
cv -iw 160 -ih 128 -a 0 -b 10 bar. -rg 1.5
Note that we use bar. as the filename; if we use bar then the input
files would be bar0.Y, ... etc. The image sequence essentially calls
the single frame display routine iteratively, so anything valid for
the single frame is valid for each frame of the image sequence.
Please see the accompanying documentation in doc.ps for more details.
FTP
cv is available by anonymous ftp from
havefun.stanford.edu:pub/cv/CVv1.2.1.tar.Z.
BUGS
Some bugs are probably lurking around. Please inform the author at
achung@cs.stanford.edu if any bugs are found.
AUTHOR
Andy Hung
- 2 - Formatted: October 25, 2025
