                      ===================================
                      AdvanceCOMP MNG Compression Utility
                      ===================================


1 SYNOPSIS
==========

advmng [-l, --list] [-z, --recompress]
	[-x, --extract] [-a, --add RATE MNG_FILE PNG_FILES...]
	[-0, --shrink-store] [-1, --shrink-fast] [-2, --shrink-normal]
	[-3, --shrink-extra] [-4, --shrink-insane] [-i, --iter N]
	[-s, --scroll HxV] [-S, --scroll-square]
	[-e, --expand] [-r, --reduce]
	[-c, --lc] [-C, --vlc] [-f, --force] [-q, --quiet] [-v, --verbose]
	[-h, --help] [-V, --version] FILES...


2 DESCRIPTION
=============

The main purpose of this utility is to recompress MNG
files to get the smallest possible size.

Please note that this utility is not able to read
a generic file. It's granted to be able to read only
the files generated by the AdvanceMAME emulator.

To compress the files this utility uses the following
strategies:

* Remove all ancillary chunks.
* Use the MNG Delta feature to compress video clips with
  only small changes between frames.
* Use the MNG Move feature to compress video clips with
  a scrolling background (option -s).
* Reduce the color depth to 8 bit (option -r).
* Use the 7zip Deflate implementation.


3 COMMANDS
==========

    -l, --list FILES...
        List the content of the specified files.

    -z, --recompress FILES...
        Recompress the specified files. If the -1, -2, -3
        options are specified, it's used the smallest file
        choice from the previous compressed data and the
        new compression. If the -0 option is specified the
        file is always rewritten without any compression.

    -x, --extract FILES...
        Extract all the .png frames in the .mng clips.
        You can use the --shrink options to control the
        compression ratio of the .png files. The extracted
        images are always 24 bit images with alpha channel.
        You can remove the alpha channel with the -n option.

    -a, --add RATE MNG_FILE PNG_FILES...
        Compress all the .png files on the command line
        as a .mng file. All the .png files must have the
        same size and the same bit depth. You must also
        specify an integer frame rate to use in the
        .mng file.


4 OPTIONS
=========

    -0, --shrink-store
        Disable the compression. The file is
        only stored and not compressed. The file is always
        rewritten also if it's bigger.

    -1, --shrink-fast
        Set the compression level to "fast" using the zlib
        compressor.

    -2, --shrink-normal
        Set the compression level to "normal" using the libdeflate
        compressor.
        This is the default level of compression.

    -3, --shrink-extra
        Set the compression level to "extra" using the 7z
        compressor.
        You can define the compressor iterations with
        the -i, --iter option.

    -4, --shrink-insane
        Set the compression level to "insane" using the zopfli
        compressor.
        You can define the compressor iterations with
        the -i, --iter option.

    -i, --iter N
        Define an additional numer of iterations for the 7z and zopfli
        compressors for modes -3 and -4.
        More iterations usually give a better compression, but may
        require a lot more time.
        Try for example with 10, 15, 20, and so on.

    -s, --scroll HxV
        The "-s HxV" option specifies the size of the pattern
        (H width x V height) used to check for a
        scrolling background. The size is expressed in
        pixels and it must be bigger or equal than the
        scrolling speed of the background. For example
        take the game 1942 that scrolls vertically by 1
        pixel every frame. If you recorded with an interleave
        factor of 2 the vertical scrolling speed is
        1*2 = 2. In this case the minimum pattern is "-s 0x2".
        Generally you can use "-s 8x8" and use bigger
        values only for games scrolling faster. If the
        game scrolls only horizontally or vertically you can
        speed up a lot the compression with monodirectional
        patterns like "-s 16x0" or "-s 0x16".

    -S, --scroll-square N
        This option is like the option "-s NxN" but excludes
        big movement on both directions reducing the computation
        time. Specifically the check done is X+Y<=N.

    -r, --reduce
        Force the color reduction to 8 bit. The reduction is
        really done only if any frame have less than 256 colors
        and if no alpha channel is present. To force the reduction
        also if an alpha channel is present use the -n option.

    -e, --expand
        Force the color expansion to 24 bit.

    -n, --noalpha
        Remove the alpha channel if present.

    -c, --lc
        Force the use of the MNG LC (Low Complexity)
        specifications. It disables the delta compression.
        The file is always rewritten also if it's bigger.

    -C, --vlc
        Force the use of the MNG VLC (Very Low Complexity)
        specifications. It disables the delta compression
        and the precise timing. Warning! you may lose the
        correct timing information because the VLC format
        only supports integer frequency. The file is always
        rewritten also if it's bigger.

    -f, --force
        Force the use of the new file also if it's bigger.

    -q, --quiet
        Don't print the filenames.

    -v, --verbose
        Print more information on the compression process.


5 EXAMPLES
==========

A good tradeoff of recompression and time is the command :

    advmng -z -r -S 16 *.mng

To create a .mng file from a series of .png files use the
command :

    advmng -a 30 video.mng video*.png

To extract all the images in a .mng file use the command :

    advmng -x video.mng


6 COPYRIGHT
===========

This file is Copyright (C) 2003 Andrea Mazzoleni, Filipe Estima


7 SEE ALSO
==========

advzip(1), advpng(1), advdef(1)
