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1993-02-03
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VOCPACK
Lossless 8-bit sound compressor/decompressor
Copyright (C) 1993 Nicola Ferioli
Version: 1.0
Date: 3 February 1993
Distribution files:
VP.EXE Ms-Dos executable
VP.DOC This document
=============================================================================
1 - INTRODUCTION
VOCPACK is a compressor/decompressor for 8-bit digital sound using a
lossless algorithm; it is useful to save disk space without degrading sound
quality.
It can compress signed and unsigned data, sampled at any rate, mono or
stereo. Since the method used is not lossy, it isn't necessary to strip
file headers before compressing.
VOCPACK was developed for use with .VOC (SoundBlaster) and .WAV (Windows)
files, but any 8-bit sound can be compressed since the program takes no
assumptions about the file structure. If you are working with signed data
(like files imported from Amiga) you should use the switch -s on the
command line to make VOCPACK work better; the default is to compress
unsigned data (SoundBlaster standard).
.MOD and .ST files are not compressed very well, since they contain a lot
of sequencing information and the sound is sampled at a low frequency; in
this case the files created by VOCPACK could be slightly bigger than the
ones produced by general-purpose compression programs.
The typical compression ratio obtained goes from 0,8 for files sampled at
11 KHz to 0,4 for 44 Khz files. The best results are obtained with 44 KHz
sounds (mono or stereo): general-purpose archivers create files that can be
twice longer than the output of VOCPACK. You can obtain smaller values
using lossy compressors but if your goal is to keep the sound quality
unaltered you should use a lossless program like VOCPACK.
=============================================================================
2 - PROGRAM NOTES
This is SHAREWARE software; you are free to copy and distribute VOCPACK on
condition that all files are included without any modification. No fee must
be charged for such distribution, except nominal fees for magnetic support,
subscription to a BBS or things like that.
VOCPACK can't be included with any commercial product without a special
license from the author.
If you find VOCPACK useful you are invited to send $5.00 (cash only) to:
NICOLA FERIOLI
VIA BOEZIO 6
21052 BUSTO ARSIZIO
ITALY
This software lets you save much more than $5.00. Sound files take a lot of
disk space: on a 1,44 MB floppy disk you can store only 33 seconds of
44 KHz music. With VOCPACK you can put at least 66 seconds of sound on the
same media, so you will gain the equivalent price of a diskette per minute
of recording.
This software is provided 'as is' with no express or implied warranty. The
author is not liable for any loss of data or other damage caused by the use
of this software.
=============================================================================
3 - USAGE
The command line of VOCPACK has the form
VP <command> [-options] <inputfile> <outputfile>
You can type VP with no parameter to obtain a short description of the
available commands and options.
File names <inputfile> and <outputfile> can't contain wildcard characters,
but may include drive and/or path. The suggested extension for compressed
files is '.VP', but the program accepts any extension.
'Command' is one of the following letters (lowercase or uppercase):
c : read sound file <inputfile> and create the compressed file
<outputfile>
d : read the compressed file <inputfile> and write the uncompressed sound
file in <outputfile>
i : display information about <inputfile>: compression method used,
original and compressed size, compression ratio; <outputfile> is
ignored and can be omitted
r : show registration information (more details can be found in section 2
of this document); the two file names are ignored
'Options' can be one or more of the following:
o : overwrite <outputfile> if it already exists; if this switch is not
present, VOCPACK asks for confirmation before overwriting; it is
used only with commands 'c' and 'd'
q : quiet mode, don't display the progress indicator; it has effect only
with commands 'c' and 'd'
s : sound to be compressed is signed; by default VOCPACK compresses
unsigned data, but to achieve a good result with files containing
signed samples you should include this option; during decompression
-s is ignored since the correct value is contained in <inputfile>
Options must be preceded by a '-' and can be placed anywhere on the command
line; they can be uppercase or lowercase and they can be combined ('-oq' is
the same of '-o -q').
=============================================================================
4 - ERROR CODES
When an error occurs, VOCPACK returns one of the following error codes (DOS
errorlevel):
1 = bad command line; the help screen was displayed
2 = input file not found
3 = output file can't be created
4 = input file is not compressed with VOCPACK
5 = user break
6 = out of memory
=============================================================================
5 - MISCELLANEOUS THINGS
This program is dedicated to Nadia Buraglio.
Thanks to Fabio Formenti and Carlo Larghi for their help & suggestions.
I have a working UNIX version of VOCPACK 1.0, but the source documentation
is quite poor and it's written in italian; if anybody is interested in
compressing sounds with UNIX, send an e-mail message to me, I could rewrite
the comments and distribute the C source code.
I am developing a different algorithm that can reduce the size of the
compressed file even more, but it is VERY slow and it could be used only on
fast processors. If registrations for version 1.0 will be enough, I'll
probably release a new version with the enhanced algorithm, maybe for 386+
machines only.
Bugs, suggestions, etc. can be e-mailed to the Internet address at the end
of this document.
This document contains trademarks registered by their respective owners.
Original distribution point: wsmr-simtel20.army.mil
Simtel20 files are also available by anonymous ftp from mirror sites
oak.oakland.edu (141.210.10.117),
wuarchive.wustl.edu (128.252.135.4),
ftp.uu.net (137.39.1.9),
nic.funet.fi (128.214.6.100),
src.doc.ic.ac.uk (146.169.3.7),
nic.switch.ch (130.59.1.40),
archie.au (139.130.4.6),
nctuccca.edu.tw (140.111.3.21),
or by e-mail through the BITNET/EARN file servers, or by uucp from UUNET's
1-900-GOT-SRCS.
Please connect to a server near you.
==========================================================================
FERIOLI NICOLA
VIA BOEZIO 6
21052 BUSTO ARSIZIO
ITALY
Internet: ser1509@cdc835.cdc.polimi.it
WARNING: this Internet address will be active until the end of January
1994; after this date I will probably change user name or I'll leave
Internet. You can contact me by mail however.