Ubuntu Manpage: pnmtoy4m - Convert PNM/PAM images to YUV4MPEG2 stream

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Provided by: mjpegtools_2.1.0+debian-4_amd64

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 interpreted 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/