xenial (1) y4mtoppm.1.gz

Provided by: mjpegtools_2.1.0+debian-4_amd64 bug

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)