Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
yuvmedianfilter(1)	      MJPEG tools manual	    yuvmedianfilter(1)

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

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

       yuvmedianfilter is designed to enhance/filter images.  It takes the in-
       put 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 al-
       ways noisy but you do not always	see it)	the output images are improved
       and the encoder spends less bandwidth encoding noise.  The more sophis-
       ticated 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.

       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  op-
	    timized  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 in-
	    terrupted job without having to duplicate work.

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

       -h   Print out a	help message

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

       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:

       For more	info, see our website at

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

y4mutils		       24 February 2003		    yuvmedianfilter(1)


Want to link to this manual page? Use this URL:

home | help