NAME

       yuvmedianfilter - A filter for yuv images produced by the mjpeg tools

SYNOPSIS

       yuvmedianfilter [-r num] [-R num] [-t num] [-T num] [-I num] [-f] [-w num] [-s num] [-v num] [-h]

DESCRIPTION

       yuvmedianfilter is designed to enhance/filter images.  It takes the input from STDIN and writes output to
       STDOUT.
       This  filter  looks  around  the  current  point  for a radius and averages the values that fall inside a
       threshold.  So the image is softened and the edges become more sharp. If the input material is noisy  (it
       is  always noisy but you do not always see it) the output images are improved and the encoder spends less
       bandwidth encoding noise.  The more sophisticated version of image filtering is yuvdenoise. But  you  can
       use  both  programs  in  the  encoding procces.  It cannot process a recorded file and write the improved
       version to another file.

OPTIONS

       yuvmedianfilter accepts the following options:

       -r num
            Radius for luma median (default: 2 pixels)

       -R num
            Radius for chroma median (default: 2 pixels)

       -t num
            Trigger threshold for luma (default: 2 [0=disable])

       -T num
            Trigger threshold for chroma (default: 2 [0=disable])

       -I num
            Interlacing type (0=no, 1=yes, default: taken from yuv stream)

       -f   Fast mode, i.e. the threshold is ignored, and a simple mean of the surrounding values is calculated.

       -w num
            In fast mode, the weight given to the current value versus the surrounding values.  Default is 8.
            Note that certain combinations of radii and weights have been optimized to be even faster --  radius
            1 and weight 2.667, radius 1 and weight 8, and radius 2 and weight 8.

       -c num
            In  slow  mode,  more  than  this fraction of the pixels must be within the threshold; otherwise the
            pixel is simply the weighted mean of pixels within a radius of 1.  Default is 0.33333.

       -s num
            Number of beginning frames to skip.  The first num frames are written to stdout unfiltered.  This is
            useful for resuming an interrupted job without having to duplicate work.

       -v num
            Verbosity level (0, 1 or 2)

       -h   Print out a help message

BUGS

       It is slow.  Using a radius greater than the default of 2 is painfully slow.

AUTHOR

       This man page was written by Bernhard Praschinger.
       The yuvmedianfilter program was written by Mike Bernson, and  adapted  to  the  yuv4mpeg2  stream  header
       format by Steven M. Schultz.

       If  you  have  questions,  remarks, problems or you just want to contact the developers, the main mailing
       list for the MJPEG-tools is:
         mjpeg-users@lists.sourceforge.net

       For more info, see our website at
              http://mjpeg.sourceforge.net

SEE ALSO

       mjpegtools(1), jpeg2yuv(1), lav2yuv(1), mpeg2enc(1), ppmtoy4m(1), yuv2lav(1), yuvdenoise(1), yuvscaler(1)

y4mutils                                        24 February 2003                              yuvmedianfilter(1)