Documentation of the AdvanceSCAN advpng utility.

1 Synopsis 

advpng [-l, --list] [-z, --recompress] [-0, --shrink-0]
    [-1, --shrink-fast] [-2, --shrink-normal [-3, --shrink-extra]
    [-4, --shrink-insane] [-i, --iter N]
    [-f, --force] [-q, --quiet]
    [-h, --help] [-V, --version] FILES...

2 Description

The main purpose of this utility is to recompress png 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:

3 Options

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