SpchComp 2.22 is a compression utility for human speech, recorded in the Microsoft Windows 
PCM WAV format.  The program may be installed by running the accompanying self-extracting
setup file "scssetup.exe" using the Windows Program Manager.  This file is freely distributable
SHAREWARE and is for evaluation only.  Any other use requires purchase of a licence (See
Ordering Information below or inside program)  

The compressed SpchComp files describe the human speech with parameters extracted out of the
original signal, based on the knowledge of the production of human speech. SpchComp uses a 
technique known as CELP (Code Excited Linear Prediction). The compression is lossy, but very
good quality can be achieved.

The compression ratio is about 25:1, or 4% of the original size. A PCM-WAV file of size 25K, 
for example, will  therefore be reduced to 1K.

The compression speed for a given file greatly depends on the power of the Processor. A typical
DX2-66 needs (in the "Best Quality" setting) roughly 11 seconds for one second of speech.
The "Fastest - Reduced Quality" setting within SpchComp reduces this to 4 seconds, but with
slightly degraded quality. The compression of files works also in the background, to enable
other tasks to be done on the computer at the same time.

File decompression rates are however better than real-time even on a slow 486.

A 16-bit Soundcard is required to make full use of SpchComp.


To compress a Windows WAV (*.WAV) file:

1. Open a file.
2. Select a *.wav-file within the Open Dialog Box.
3. Click OK.
4 Click on the Compress button.
5. State filename and directory in the Save as... Dialog Box.
6. Click OK.

The sound quality of the compressed SpchComp-file depends on the Compression speed settings in 
the Options Dialog Box.

To decompress or expand a SpchComp (*.SPC) file:

1. Open a file.
2. Select a *.SPC-file within the Open Dialog Box.
3. Click OK.
4. Click on the Expand button.
5. State filename and directory in the Save as... Dialog Box.
6. Click OK.

The decompression speed can be significantly increased by disabling the Status Bar in the
Options Dialog Box.

To play a Windows WAV (*.WAV) or SpchComp (*.SPC) file:

Click the Play button.

A SpchComp file is automatically decompressed into a temporary file and then sent to the 
Soundcard.  Playback may be paused or halted as required.

Purchase of this software, and any queries regarding it, should be addressed to

Voyce Technology
36539 Montecito Drive
Fremont, CA  94536
USA

Tel / Fax : USA   510  4940201

See also Ordering Information inside program.