NAME

       ppmtoy4m - Convert PPM images to YUV4MPEG2 stream

SYNOPSIS

       ppmtoy4m [options] [ filename ]

DESCRIPTION

       ppmtoy4m  converts  one  or  more  raw PPM images into a YUV4MPEG2 stream ready for further processing by
       other video tools.

       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 PPM image, read from stdin or from the optional filename.  The input may contain
       multiple PPM images concatenated together; ppmtoy4m will read and process them sequentially.  All  images
       must  have  identical  size  and  format.   Input  images can be interpreted as whole progressive frames,
       interleaved fields, or (in pairs) as sequential fields.  The input images must have 8  bits  per  channel
       (i.e. 'maxval' must be 255).

       Input images should be in the usual R'G'B' colorspace.  They are converted to the Y'CbCr colorspace (ITU-
       R BT.601) (and chroma subsampled, if desired) before output.

       ppmtoy4m  and  y4mtoppm  are  inverses  of each other; you can pipe the output of one into the other, and
       vice-versa.  Note that the subsampling and colorspace 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

       ppmtoy4m 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)

       -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

       -B   Interpret data as being BGR rather than RGB.

       -I x Set interlacing mode, used to interpret the  PPM  image(s),  and  also  encoded  in  output  stream.
            (default:  'p')
             p - progressive, non-interlaced
             t - top/upper-field-first interlaced
             b - bottom/lower-field-first interlaced

       -L   For  interlaced streams, treat each PPM image as two interleaved fields.  (Otherwise, two PPM images
            will be read for each frame; one per field.)

       -r   Repeat last input frame until output is complete.  If '-n 0' is also  specified,  last  input  frame
            will be repeated forever.

       -S mode
            Set chroma subsampling mode.  (default:  444)
                   444 - 4:4:4 (no subsampling)
               420jpeg - 4:2:0 JPEG/MPEG-1, interstitial cositing
              420mpeg2 - 4:2:0 MPEG-2, horizontal cositing

            The  subsampled modes use a lousy subsampling filter; better results will be achieved by passing the
            default 4:4:4 output to a scaler which supports subsampling, such as y4mscaler(1).

       -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:

            ppmtoy4m -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 | ppmtoy4m | yuvplay

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), y4mtoppm(1), mjpegtools(1), mpeg2enc(1), y4mscaler(1), yuv2lav(1), yuvplay(1)

MJPEG Tools Team                                  28 April 2004                                      ppmtoy4m(1)