y4munsharp(1) [suse man page]
y4munsharp(1) MJPEG tools manual y4munsharp(1) NAME
y4munsharp - Unsharp filter for YUV4MPEG2 streams SYNOPSIS
y4munsharp [options] DESCRIPTION
y4munsharp is an implementation of the GIMP unsharp filter for YUV4MPEG2 streams. The usual 3 parameters for unshap mask processing (radius, amount and threshold) are specified on the command line. By default only the Y' (luma) component is processed although processing of the CbCr (chroma) may be requested by a commandline option. Output must be either to a pipe or a file, leaving stdout as a terminal will elicit an error and the program will exit. OPTIONS
y4munsharp accepts the following options: -v num Set verbosity level (0 = quiet, 1 = normal, 2 = debug) (default: 1) -h Print a suage summary and exit -L radius,amount,threshold Y' (luma) unsharp parameters. The radius and amount" arguments are floating point numbers. The threshold argument is an integer. (default: 3.0,0.3,4) -C radius,amount,threshold CbCr (chroma) unsharp parameters. The chroma is not processed unless this option is given. Arguments are the same type as for the -L option above. (default: none) -N Filtering can produce output outside the 16 to 240 range for Y' and 16 to 235 for CbCr. By default values outside the legal range are clipped/cored (values over 240 for Y' are set to 240 for example). Using -N the limits 0 and 255 are used instead. EXAMPLES
A mild setting: y4munsharp -L 2.0,0.3,0 An aggressive setting: y4munsharp -L 5.0,0.5,0 NOTES
The radius, amount, threshold parameters have the same meaning as the GIMP's unsharp plugin. This means you can use the GIMP on selected frame still images to determine suitable settings for y4munsharp. The key thing to remember is to be subtle - you just barely want to notice the sharpening effect. If the effect is obvious ("jumps out at you") then the parameters are set too aggressively. The chroma is not processed for a several reasons: 1) The eye is much more sensitive to changes in brightness, 2) the chroma is usually subsampled and doesn't contribute much to the perceived sharpness of an image - so not processing the chroma provides a boost in speed of processing the image, and 3) possible artifacting - changes in Y' just make an image brighter/darker but changes in Cb or Cr can change colors and possibly lead to shifts in hue. Use the -C option to enable processing of the chroma planes. BUGS
Only the 3 plane YUV4MPEG2 formats are supported. Only progressive, top field first or bottom field first interlaced streams are handled. The mixed interlaced stream format is not sup- ported. MJPEG Linux Square 11 November 2004 y4munsharp(1)
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pnmtoy4m(1) MJPEG tools manual pnmtoy4m(1) NAME
pnmtoy4m - Convert PNM/PAM images to YUV4MPEG2 stream SYNOPSIS
pnmtoy4m [options] [ filename ] DESCRIPTION
pnmtoy4m converts one or more raw PPM, PGM, PBM, or PAM images into a YUV4MPEG2 stream ready for further processing by other video tools. These three (or four) image formats are collectively referred to as "PNM images". Output is to stdout to facilitate piping to other MJPEG tools. The size of the output frame(s) is determined from the (first) input image. Input is a 'raw' format PNM image, read from stdin or from the optional filename. The input may contain multiple PNM images concatenated together; pnmtoy4m will read and process them sequentially. All images must have identical size and format. Input images can be inter- preted as whole progressive frames, pairs of interleaved fields, or as sequential fields (read in pairs of images) to be output as either interlaced or progressive frames. PPM and PGM images must have 8 bits per channel (i.e. 'maxval' must be 255). PPM input images should be in the usual R'G'B' colorspace. They are converted to the Y'CbCr colorspace (ITU-R BT.601) before being output to a "4:4:4" (non-subsampled) YUV4MPEG2 stream. If chroma subsampling is required (e.g. to 4:2:0 for MPEG), the output should be further piped through a program such as y4mscaler. PGM images should be in the standard full-range ([0,255]) grayscale colorspace. PGM and PBM images will be converted to BT.601 luma and output as "MONO" (luma-only) YUV4MPEG2 streams. The PAM format is a newer superset of the PNM formats; the precise contents of a PAM image is defined by the TUPLTYPE header tag. pnmtoy4m handles TUPLTYPE "GRAYSCALE" as PGM, "RGB" as PPM, and "RGB_ALPHA" as PPM with an 8-bit alpha channel. (The alpha channel is converted to BT.601 luma as is appropriate for YUV4MPEG2 streams.) pnmtoy4m and y4mtopnm are inverses of each other; you can pipe the output of one into the other, and vice-versa. Note that the colorspace operations are lossy in both directions. And, when converting to PNM, information on interlacing and sample aspect ratio is lost (but can be reconstructed by supplying command-line arguments to pnmtoy4m). OPTIONS
pnmtoy4m accepts the following options: -o num Frame offset: skip output of the first 'num' frames. (default: 0) -n num Output a total of 'num' output frames. Use '0' to specify all frames. (default: 0) -B Interpret data as being BGR rather than RGB. -r Repeat last input frame until output is complete. If '-n 0' is also specified, last input frame will be repeated forever. -D x Treat each PNM image as a single (de-interleaved) field instead of a full frame. The argument specifies the interpretation: t - the first image is a top-field b - the first image is a bottom-field With this option, two input images will be required per output frame. Be careful: mismatched "-I" and "-D" options can invert the temporal or spatial order of the fields (or both). -F n:d Set framerate encoded in output stream, as an exact integer ratio. (default: 30000:1001) Common rates are: 24000:1001 - NTSC 3:2 pulldown converted film 24:1 - native film 25:1 - PAL/SECAM 30000:1001 - NTSC video 50:1 - PAL field rate 60000:1001 - NTSC field rate -A n:d Set pixel aspect ratio encoded in output stream, as an exact integer ratio. (default: 1:1) Common ratios are: 1:1 - square pixels (computer graphics) 10:11 - CCIR-601 NTSC 59:54 - CCIR-601 PAL -I x Set the output interlacing mode, encoded in the output stream. (Default is to match "-D" if given, or 'p' if not.) p - progressive, non-interlaced t - top/upper-field-first interlaced b - bottom/lower-field-first interlaced -v [0,1,2] Set verbosity level. 0 = warnings and errors only. 1 = add informative messages, too. 2 = add chatty debugging message, too. EXAMPLES
To convert a file containing a single PPM file into a stream of 15 (identical) frames: pnmtoy4m -n 15 -r some-image.ppm To convert a series of Targa format images (in the current directory) to a YUV4MPEG2 stream displayed by yuvplay: ls *.tga | xargs -n1 tgatoppm | pnmtoy4m | yuvplay AUTHOR
This manual page was written by Matt Marjanovic. 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
pam(5), pbm(5), pgm(5), pnm(5), ppm(5), y4mtopnm(1), mjpegtools(1), mpeg2enc(1), y4mscaler(1), yuv2lav(1), yuvplay(1) MJPEG Linux Square 28 April 2004 pnmtoy4m(1)