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- CMPWAV - Compress .WAV Files
-
-
- Syntax
-
- cmpwav sndfile
-
- cmpwav [-amw] sndfile
-
- cmpwav sndfile.wav
-
- cmpwav source[.wav] [target[.wav]]
-
-
- Options
-
- a - use ALAW method
- m - use MULAW method
- w - use MSADPCM method
-
- Usage
-
- Use "cmpwav" to compress and uncompress .wav files using
- any one of a variety of different formats.
-
- The program will compress uncompressed files,
- and uncompress compressed files.
-
- The program will compress/uncompress a file "in-place",
- by first saving the output in a temporary file, then
- removing the target file (if it exists) and renaming the
- file containing the generated output.
-
- If the eventual output file is read-only, the
- program will change the file attribute, remove
- it, rename the temporary file, then reset the
- read-only attribute.
-
- The program will prompt for a compression method, unless a
- method is specified on the command line or if the program is
- going to uncompress the file.
-
- The program "tpcm.exe" is synchronized with this program, in
- that what cmpwav writes, tpcm will read. (Use "tpcm" to
- play and display .wav files, after loading the TSR "pcm.com".)
-
-
- Examples
-
- C:> cmpwav sndfile
-
- This example will cause the program to look for the file
- "sndfile.wav", prompt for a compression method, then perform
- the action and save the output in the same file "sndfile.wav",
- assuming "sound.wav" is an uncompressed file.
-
- If the file "sndfile.wav" is already compressed, then the
- the program will uncompress the data back into "sndfile.wav".
-
- C:> cmpwav -a sound.wav
-
- This command will compress the data in the file "sound.wav"
- using the ALAW method, saving the output in "sound.wav".
-
- C:> cmpwav -a sound soundcmp
-
- This command will compress the data in the file "sound.wav"
- using the ALAW method, saving the output in "soundcmp.wav".
-
-
- Limitations
-
- Compresses 16-bit files only.
-
- Can not "uncompress" and "compress" in the same command;
- that is, will not read a file compressed with one format,
- uncompress it and generate a compressed file in another
- or different format.
-
-
- Caveats
-
- Attempts to process files not conforming to its requirements
- (non 16-bit files, unrecognized formats, etc.) may generate
- unpredictable results, although every attempt has been made
- to eliminate crashes, hangs and lock-ups.
-
- ADPCM Compression Algorithm: Microsoft Corporation 8/20/1992
- From the Multimedia Standards Update 8/20/92
-
- MULAW, ALAW, IMA Compression Algorithms: various public domain
- sources.
-
- We use wavformat.fmttag == 3 for "IMA", whereas this value has
- not been defined by Microsoft; this may cause incompatibilty
- problems in the future.
-
- =======================================================================
- Copyright (c) 1992. Media Vision, Inc. All Rights Reserved.
- Programmers: Bart Crane, Shao Ma
-
-
-