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)