y4mtoppm(1) [debian man page]

y4mtoppm(1)							MJPEG tools manual						       y4mtoppm(1)

NAME

       y4mtoppm - Convert YUV4MPEG2 stream to PPM images

SYNOPSIS

       y4mtoppm [options]

DESCRIPTION

       y4mtoppm converts a YUV4MPEG2 stream into a sequence of raw PPM images.

       Output is to stdout (but feel free to have the shell redirect to a file).

       Input  is read from stdin, like all other YUV4MPEG2 filters and tools.  YUV4MPEG2 streams contain frames using the Y'CbCr colorspace (ITU-R
       BT.601).  y4mtoppm will convert each pixel to the usual R'G'B' colorspace used for computer graphics.

       YUV4MPEG2 streams may (often!) have subsampled chroma planes.  y4mtoppm can upsample "4:2:0 JPEG" streams using a simple, lousy	algorithm.
       Better results will be obtained using a filters such as y4mscaler(1) which are capable of general-purpose subsampling operations.  y4mtoppm
       will fail on streams which have chroma subsampling modes other than 4:4:4 or 4:2:0-JPEG.

       For interlaced streams, these operations are performed on each field individually.  Fields can be output as separate PPM  images  in  time-
       order (default), or interleaved into full-frame images.

       If  multiple  PPM images are generated, they are simply output one after another.  If you want to turn such a "multi-image" PPM stream/file
       into individual files, use pnmsplit.  (Some PNM filters can process multi-image files/streams; however, many written before June 2000  will
       only process the first image.)

       y4mtoppm  and ppmtoy4m are inverses of each other; you can pipe the output of one into the other, and vice-versa.  Note that the colorspace
       (and subsampling) operations are lossy in both directions.  And, when converting to PPM, information on interlacing and sample aspect ratio
       is lost (but can be reconstructed by supplying command-line arguments to ppmtoy4m).

OPTIONS

       y4mtoppm accepts the following options:

       -L   For  interlaced streams, output a single PPM image for each frame, containing two interleaved fields.  (Otherwise, two PPM images will
	    be generated for each frame; one per field.)

       -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 turn the first 15 frames of an (MJPEG or DV) AVI file into individual PPM files:

	    lav2yuv -f 15 your-video.avi | y4mtoppm | pnmsplit - "your-video-%d.ppm"

AUTHOR

       This man 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

       ppm(5), pnm(5), ppmtoy4m(1), mjpegtools(1), mpeg2enc(1), lav2yuv(1), pnmsplit(1), y4mscaler(1)

MJPEG Linux Square						   28 April 2004						       y4mtoppm(1)

Check Out this Related Man Page

jpeg2yuv(1)							MJPEG tools manual						       jpeg2yuv(1)

NAME

       jpeg2yuv - Convert jpeg images to the yuv format.

SYNOPSIS

       jpeg2yuv [-b num] [-f num] [-I num] [-A ratio] [-L num] [-n num] [-l num] [-j filename]

DESCRIPTION

       jpeg2yuv decompresses a sequence of JPEG files and pipes the image data to stdout as a YUV4MPEG2 stream.  Any JPEG format supported by lib-
       jpeg can be read.  stdout will be filled with the YUV4MPEG2 movie data stream, so be prepared to pipe it on to mpeg2enc or to write it into
       a file.

OPTIONS

       jpeg2yuv accepts the following options:

       -b num
	    Frame offset:  skip output of the first 'num' frames.  (default: 0)

       -f num
	    Set the frame rate of stream accepts the same numbers.  No default, this option has to be specified.

       -A ratio
	    Sample aspect ratio.  Default is square pixels (1:1)

       -I num
	    interlacing mode: p = none / progressive
	    t = top field first
	    b = bottom field first
	    No default, this option has to be specified.

       -L num
	    0 = non-interlaced (two successive fields per JPEG file)
	    1 = interlaced fields

       -l num
	    Specifies the number of loops (default: 0 loops )
	    When  this	option	is  not used the given range of images is only processed once. If you use this option with num of -1 jpeg2yuv will
	    loop forever writing the image to stdout. When you use n > 0 it will loop n-times till it finishes.

       -n num
	    Specifies the number of frames to process. (default: all = -1)

       -j {1}%{2}d{3}
	    Read JPEG frames with the name components as follows:
	     {1} JPEG filename prefix (e g: picture_ )
	     {2} Counting placeholder (like in C, printf, eg 06 ))
	     {3} File extension. Something like this: .jpg A correct description of the files could look like this: picture_%06d.jpg

	    If this option is omited, the filenames are read from stdin. For example:
	     $ls *jpg | jpeg2yuv -f 25 -I p > result.yuv

       -R 1 or 0
	    rescale YUV color values from 0-255 to 16-235 (default: 1)

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

BUGS

       The frame rate description seems not to be up to date. The NTSC integer ratios seem not to be supported. As a workaround specify a PAL (25)
       or FILM (24) and set the right frame rate in mpeg2enc with the -F option.

AUTHOR

       This man page was written by Bernhard Praschinger.
       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), mpeg2enc(1), ppmtoy4m(1), yuv2lav(1), yuvdenoise(1), yuvmedianfilter(1), yuvscaler(1)

MJPEG Linux Square						  8 December 2001						       jpeg2yuv(1)

Linux and UNIX Man Pages

y4mtoppm(1) [debian man page]

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