packARC v0.7RC18 (12/17/2014)


packARC is an archiver program specially designed for lossless further 
compression of media files in the JPEG, MP3, BMP and PNM formats. It 
contains all of my latest developments, the packJPG, packMP3, packPNM 
and packARI algorithms with an easy to use command line interface. 
Typical further compression for JPEG is ~20%, for MP3 it is ~16% and for 
PNM, BMP and other file types it is highly dependent on the contents of 
the file. 

packARC creates .pja archives, which may contain several files of 
arbitrary file type. In general packARC is not as efficient as ZIP, RAR, 
or 7z when compressing generic files, but it performs very good for JPG, 
MP3, BMP and PNM-files. 

Besides the archiver program, packARC, this package also contains the 
source code for packJPG, packMP3, packPNM, and packARI. packJPG, 
packMP3, packPNM and packARI do not create archives, but compress JPG, 
MP3, PNM or, in the case of packARI, generic files on a file by file 
basis. 


LGPL v3 license and special permissions

All programs in this package are free software; you can redistribute them and/or modify them under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

The package is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details at http://www.gnu.org/copyleft/lgpl.html.

If the LGPL v3 license is not compatible with your software project you might contact us and ask for a special permission to use packARC or the packANY library under different conditions. In any case, usage of the packARC algorithm under the LGPL v3 or above is highly advised and special permissions will only be given where necessary on a case by case basis. This offer is aimed mainly at closed source freeware developers seeking to add packARC support to their software projects.

Compression algorithms and file types


packARC contains four unique compression algorithms, packJPG, packMP3, 
packPNM and packARI in one easy to use command line interface. Files 
will be compressed into either the regular PJA (packJPG Archive) or SFX 
(self extracting archive) formats. SFX archives are executable files 
that extract their own contents upon execution. 

packARC will handle any type of file. Folders specified as file name are 
recursed and all contained files added to the archive while preserving 
relative folder structure. For regular files, the compression algorithm 
to use is decided on a per file base, automatically analyzing each file 
before adding it to the archive. 

The packJPG algorithm handles image files in the JPEG file format. 
Basically all types of JPEG files, baseline, extended sequential, 
progressive, CMYK and YCbCr are supported by packJPG. 

The packMP3 algorithm handles audio files in the MPEG-1 Audio Layer III 
format. Files in MPEG-2/2.5 Audio Layer III format are not supported. 
You may distinguish these from MPEG-1 Audio Layer III by their sample 
rates. Only MPEG-1 Audio Layer III supports sample rates of 32kHz and 
above. 

The packPNM algorithm handles image files in the BMP format and the PPM 
8bit/16bit, PGM 8bit/16bit and PBM binary formats (the respective ASCII 
based formats are not supported). Unless the image file has structural 
errors it will always be compressed using the packPNM algorithm.

All other and unrecognized files are handled by the packARI algorithm, 
which consists of arithmetic coding with a simple variable order 
statistical model. 


Usage of packARC
~~~~~~~~~~~~~~~~

The following paragraphs explain the general usage of packARC. In these 
praragraphs, [] is used for required paramters, <> is used for optional 
parameters. 

You may create a new PJA archive or add files to an existing archive 
using this command: 

 "packARC a <switches> [name_of_archive] [file(s)_to_add]"

When extracting, specifying files to extract is optional as indicated by 
the <>. If you leave it blank, all files inside the archive are 
extracted. To extract files from an existing archive use this command: 

 "packARC x <switches> [name_of_archive] <file(s)_to_extract>"
 
packARC can extract archive contents to memory and compare extracted 
CRC32s with original CRCs, making sure that all files inside the archive 
are ok. To test archive integrity, use this command: 

 "packARC t [name_of_archive]"
 
To convert an existing regular archive to SFX (self extracting archive) 
format or to convert an SFX archive to regular archive format use the 
following command. packARC will automatically choose the direction of 
the conversion based on the format of the input archive. 

 "packARC c [name_of_archive]"
 
You may delete unwanted files from an archive using the delete command. 
Use this syntax: 

 "packARC d [name_of_archive] [file(s)_to_delete]"
 
To list the contents of an archive, use the list command:

 "packARC l <switches> [name_of_archive]"
 
packARC handles SFX archives the same way as it handles regular 
archives. You may use all of the mentioned commands on either regular 
packARC archives or on packARC SFX archives created in any OS. packARC 
is also compatible with archives written using previous release 
versions. You can edit, extract, test, convert and add to archives 
created with older versions, too. 

packARC supports wildcards like "*.*" and drag and drop of multiple 
files. When dropping an archive file, that file is extracted in place. 
When dropping multiple files and/or non-archive files, a new SFX archive 
file is created using the name of the first file in the list and all 
files are added to it. Existing archive files won't be changed or 
overwritten in the process. 

In default mode, existing files are never overwritten, neither inside, 
nor outside the archive. packARC skips these files instead. You may 
configure this behaviour to your liking using command line switches 
"-o", "-s" and "-r" (see below). 

Usage examples:

Add all files matching "*.jpg" to archive "image.pja":
 "packARC a images.pja *.jpg"

Extract all files from archive "media.pja":
 "packARC x media.pja"
 
Delete file "unneeded.txt" from archive "SFX.exe":
 "packARC d SFX.exe unneeded.txt"
 
Convert archive "archive.pja" to SFX format:
 "packARC c archive.pja"
 
List contents of archive "myfiles.exe":
 "packARC l myfiles.exe"


Command line switches
~~~~~~~~~~~~~~~~~~~~~

 -o    overwrite existing files
 -s    skip existing files (default)
 -r    rename on existing files
 -i    (with x) ignore crc errors
 -sfx  (with a) create sfx archive
 -sl   (with l) simple list format
 -csv  (with l) CSV list format
 -np   no pause after processing.
 
 
When adding or extracting, existing files are skipped by default. If you 
want packARC to overwrite files, use "-o". If the command line parameter 
"-r" is used and a filename is already in use, packARC will create a new 
filename by adding underscores to the original filename instead. As an 
example, if "lena.jpg" already existed, the new file would be called 
"lena_.jpg when "-r" is used. 

By default, packARC checks extracted files using CRC32. If the check 
fails, packARC does not extract the file in question and moves on to the 
next file instead. In theory the check should never fail, but it may 
happen with corrupted archives. If you want to disable the CRC32 check 
for any reason use the parameter "-i". 

If you want to create a new SFX archive, you don't need to create a 
regular one first using "a", then convert it it using "c". Just use the 
switch "-sfx" in conjunction with "a" to create a SFX archive right 
away. 

You can change the format of the file listing with "l". For a simpler 
list format use switch "sl". For CSV compatible output use switch "csv". 

Usage examples:

Add all files matching "newfile??.bin", overwriting existing files:
 "packARC a -o archive.pja newfile??.bin"
 
Create new SFX archive adding all files matching "*.mp3":
 "packARC a -sfx music.exe *.mp3"
 
Extract archive, skipping CRC32 check and renaming on existing files:
 "packARC x -r -i photos.pja"
 
List contents of archive using the CSV list format:
 "packARC l -csv compressed.exe"


Known Limitations 
~~~~~~~~~~~~~~~~~ 

Although packARC can handle any type of file, it was mainly designed 
with media files MP3 and JPEG in mind. It will reasonably compress the 
occasional TXT, PDF, DOC or any other file, but it is not intended to be 
used for large files such as ISOs. If the files that you want to archive 
don't consist mainly of JPEGs or MP3s you might want to consider using 
something else, such as Matt Mahoney's excellent PAQ8 series of 
archivers from http://www.mattmahoney.net/dc/.

There is low error tolerance for JPEG and MP3 files. Even if a file can 
be perfectly processed by image viewer or audio player software, it 
might not be standard compliant. If a file is not 100% standard 
compliant, it won't be processed with the appropriate media compression 
algorithm. The generic algorithm is used instead, thus generating output 
of bigger size than you might expect. You may check the archive file 
listing to see which algorithm was used for the file included in an 
archive. 

If you try to drag and drop too many files in Microsoft Windows at once, 
there might be a windowed error message about missing privileges. In 
that case you can try it again with less files or consider using the 
command prompt. packARC has been tested to work properly with thousands 
of files from the command line. This issue also happens with drag and 
drop in other applications, so it might not be a limitation of packARC 
but a limitation

PackARC

Install / Use

README