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SSSSSSS OOOOO N N A RRRRRRR CCCCCC S S O O NN N A A R RR C C S S O O N N N A A R R C C S O O N N N A A R R C SSS O O N N N A A R RR C SSS O O N N N A A RRRRRRR C SSS O O N N N AAAAAAAAAAA R R C S O O N N N A A R R C S S O O N N N A A R R C C S S O O N NN A A R R C C SSSSSSS OOOOO N N A A R R CCCCCC SONARC: Digital Audio Compression, Version 2.1h ─────────────────────────────────────────────── (C) Copyright 1994 Speech Compression All Rights Reserved U S E R M A N U A L June 1994 SONARC version 2.1h Copyright 1994 Speech Compression Page i ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ CONTENTS INTRODUCTION .......................................................... 1 THE UTILITIES ......................................................... 2 SONARC.EXE .......................................................... 2 SONARCX.EXE ......................................................... 5 LICENSING INFORMATION ................................................. 6 OTHER LICENSABLE MODULES .............................................. 7 SONLIB.DLL .......................................................... 7 LINKABLE OBJECTS .................................................... 9 POSTSCRIPT ........................................................... 11 LEGAL MUMBO-JUMBO AND ACKNOWLEDGMENT OF TRADEMARKS Even though Speech Compression has tested the Sonarc software and reviewed the documentation, SPEECH COMPRESSION MAKES NO WARRANTY OR REPRESENTATION, EITHER EXPRESSED OR IMPLIED, WITH RESPECT TO SONARC SOFTWARE, ITS QUALITY, PERFORMANCE, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE. AS A RESULT, THIS SOFTWARE IS PROVIDED "AS IS", AND YOU, THE USER, ARE ASSUMING THE ENTIRE RISK AS TO ITS QUALITY AND PERFORMANCE. IN NO EVENT WILL SPEECH COMPRESSION BE LIABLE FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES RESULTING FROM ANY DEFECT IN SONARC SOFTWARE OR ITS DOCUMENTATION, even if advised of the possibility of such damages. In particular, Speech Compression shall have no liability for any programs or data used with Sonarc software, including the cost of recovering such programs or data. Sonarc, Sonarcx and ZipTalk are trademarks of Speech Compression. Microsoft and MS-DOS are registered trademarks and Windows is a trademark of Microsoft Corporation. BORLAND is a registered trademark of Borland International, Inc. PKZIP is a registered trademark of PKWARE Inc. All other brand and product names mentioned are trademarks or registered trademarks of their respective holders. SONARC version 2.1h Copyright 1994 Speech Compression Page 1 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ INTRODUCTION Sonarc is a new compression technology specifically optimized for digital audio. Think of Sonarc as the PKZIP(r) of digitized audio. Unlike the older ADPCM techniques, Sonarc features variable-rate compression which can be reversed to precisely reconstruct the original, uncompressed signal. You don't need to judge its quality by listening to the original and decompressed versions of the signal; just run MS-DOS's COMP or FC commands! What's the average amount of compression achievable with Sonarc? Obviously, truly random sequences of numbers (white noise) will not compress at all losslessly. On the other hand, there are 8-bit, 22 KHz sound-effects files in products on the market today for which Sonarc achieves an average of 3:1 lossless compression (see below). It all depends upon the quality of the recording and sampling and on the nature of the audio signal being processed. The grand average compression of all 8-bit, 11 KHz WAVE and VOC files that have been processed so far by Sonarc is about 55% (over 2:1). Sonarc was not intended to be a general-purpose data compression utility, like the other compressors to which it is compared below. In fact, Sonarc does only a mediocre job of compression on files which contain non-audio data. The following comparison is not for the purpose of denigrating the other compression products, but simply to show how well Sonarc is adapted to the compression of audio data. The four files used in this comparison are probably the most widely distributed audio files in the world, since they come with each copy of Microsoft's Windows v3.1. File Original size LHA v2.13 PKZIP v2.04g Sonarc v2.1h ─────────────────────────────────────────────────────────────────────────── CHIMES.WAV 15,920 8,680 8,690 4,170 CHORD.WAV 24,982 9,407 8,861 7,174 DING.WAV 11,598 4,704 4,630 2,184 TADA.WAV 27,804 18,388 18,566 11,528 ────── ────── ────── ────── 80,304 41,179 40,747 25,056 The command-line option -ex (Maximum Compression) was used with PKZIP. Sonarc used the command-line options -o0 and -x for maximum compression. The compressed file sizes reported for LHA and PKZIP are the internal file sizes and do not include the archive directory overhead. SONARC version 2.1h Copyright 1994 Speech Compression Page 2 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ THE UTILITIES Compression and decompression are accomplished using the programs SONARC.EXE and SONARCX.EXE, respectively. Both programs use a simple command-line interface. Typing SONARC or SONARCX alone at the DOS prompt will cause the program to display a little "help" screen, explaining the syntax of the command line parameters. Monaural and stereo, 8-bit and 16-bit files are supported in both WAVE and VOC formats. Creative Labs' new v1.20 VOC files are fully supported. Neither utility uses extended or EMS memory. Both use less than 256K of conventional memory. Both utilities run on 8086 processors; however, when processing 16-bit data, they "sense" whether they are executing on a '386 or better, and if so, will use the '386 instruction set for faster execution. SONARC.EXE (file-to-file compression program) ─────────────────────────────────────────────────────────────────────────── The syntax for invoking SONARC is: SONARC {-<option>} <input-file> [<output-file>] or SONARC {-<option>} <wildcarded-name> [<dest-path>] If the input file has an extension, then it must be supplied. If the input file is not in the current directory, then the path needed to reach it from the current directory is also required. The output file specification is optional. If it is omitted, then the output file will be created in the current directory with a name which is formed by concatenating the root name in the input file with one of the extensions shown below. If it is supplied, then a path can be specified to cause the output file to be written to a directory other than the current directory. If no extension is specified for the output file, the extension will be WV, VC, or SNC, depending on whether the input file is in WAVE, VOC, or another format, respectively. (SONARC scans the beginning of the file for a WAVE or VOC header. If it finds neither, it assumes the file is "raw", i.e., contains only audio samples; it then prepends its own header to the output file.) Alternatively, a wild-card specification (with source path, if needed) can be used. If a destination path is supplied, the output files will be written to that path, otherwise to the current directory. Any destination name or extension will be ignored. If the input file to Sonarc is a WAVE file, then the output file is also a WAVE file in a special, proprietary format which has been registered with Microsoft's Multimedia Product Management. Although the letter options are shown on the next page in upper case, they can be entered in either upper or lower case. The option prefix character may be either a '-' or '/'. SONARC version 2.1h Copyright 1994 Speech Compression Page 3 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ The command-line options for SONARC.EXE are: Q quiet mode: no banners, no statistics, no warning for overwriting existing files. D delete the input file upon successful operation. S[n] (used with "raw" files) assume stereo (two interleaved tracks, or "n" interleaved tracks if the optional number "n" is specified). The default is to assume that the "raw" file is monaural. 16 assume 16-bit samples, if the input file is "raw". The default for "raw" files is to assume that they are all 8-bit samples. Options S and 16 may be used together to compress "raw" 16-bit, stereo files. Fnum set the frame size to num in the range 256-4096. Sonarc divides the source into "frames" of so many samples each. The compressed file then consists of compressed "frames", each of which contains table data specific for that frame. If the frame size is too small, then the size of the table data will not be amortized over enough compressed samples and the compression ratio will suffer. If the frame size is too big, then spectral changes within the frame will not be tracked accurately enough, and so the compression ratio will suffer for that reason. Different files will have different "optimal" values for frame size. This option overrides the default frame size of 2048. Onum set order to num in the range from 0 to 30. "Order" is the number of previous samples to take into consideration when attempting to predict the next sample. This option fixes the order to the number specified, except that a num of 0 causes the program to "search" for the best value of order for each frame. This added searching will slow the compression process substantially, but generally yields more compression. The default order is 10. X use floating-point calculations to analyze the signal more thoroughy than is otherwise done (the default is to use fixed- point integer arithmetic). Setting this option will slow the compression process moderately, or immoderately if combined with the -o0 option described above. The floating-point code uses a "sensing" library that uses a co-processor if detected at run-time. A co-processor is not necessary, but is highly recommended nevertheless for the sake of compression speed. SONARC version 2.1h Copyright 1994 Speech Compression Page 4 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Examples: SONARC C:\WIN31\*.WAV Compress all the .WAV files in the C:\WIN31 directory and write the output to the current directory SONARC /D ILBEBACK.WAV .. Compress ilbeback.wav in the current directory to ilbeback.wv, in the parent directory. Erase ilbeback.wav if no errors occur. sonarc -q *.voc d: Compress all the .VOC files in the current directory and write the corresponding .VC files to the current directory of the D: drive. Suppress all screen output. sonarc piano.sou pno (assuming piano.sou is "raw":) Compress piano.sou to pno.snc sonarc -s piano.sou pno.cmp Compress piano.sou to pno.cmp; assume the samples are interleaved stereo tracks sonarc -16 piano.sou pno. Compress piano.sou to pno; assume piano.sou is sampled at 16 bits sonarc -x -o0 g145.wav Compress g145.wav for maximum compression ratio, at the expense of considerable extra time in compressing the file SONARC version 2.1h Copyright 1994 Speech Compression Page 5 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ SONARCX.EXE (file-to-file decompression program) ─────────────────────────────────────────────────────────────────────────── The syntax for invoking SONARCX is: SONARCX {-<option>} <input-file> [<output-file>] or SONARCX {-<option>} <wildcarded-name> [<dest-path>] The input (compressed) file specification requires the file's extension, if any. (This will be the extension specified for the output file during the execution of SONARC, or else WV, VC, or SNC, if no extension was specified.) If the input file is not in the current directory, then the path needed to reach the file from the current directory is also required. The output (decompressed) file specification is optional. If it is omitted, then the output file will be created in the current directory with a name which is formed by concatenating the root name in the input file with one of extensions described below. If it is supplied, then a path can be specified to cause the output file to be written to a directory other than the current directory. If no extension is specified for the output file, the extension will be WAV, VOC, or the original file's extension in the case where the original file was not in either WAVE or VOC format. Alternatively, a wild-card specification (with source path, if needed) can be used for specifying the input (compressed) files. If a destination path is supplied, then the output (decompressed) files will be written to that path, otherwise to the current directory. Any destination name or extension will be ignored. Since Sonarc is a LOSSLESS compression technology, the decompressed and original files will differ only in their timestamps. They will otherwise compare identically, using the FC or COMP commands in DOS. The command-line options for SONARCX.EXE are: Q quiet mode: no banners, no statistics, no warning for overwriting existing files. D delete the input file upon successful operation. Examples: SONARCX *.WV Decompress all the .WV files in the current directory and write the reconstructed files to the current directory sonarcx -q *.vc d:\ Decompress all the .VC files in the current directory and write the corresponding .VOC files to the root directory of the D: drive. Suppress all screen output. sonarcx pno.snc piano Decompress pno.snc to piano.sou (if "sou" was the extension on the original file, stored in the pno.snc file header). SONARC version 2.1h Copyright 1994 Speech Compression Page 6 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ LICENSING INFORMATION What you may do with Sonarc depends on what classification you fall under. The archive referred to is the SNRC21.ZIP file from which this file was extracted. 1. Shareware distributors, computer clubs and user groups: Members of this category are permitted to distribute this archive along with other shareware programs as long as the charge for the diskette containing this archive does not exceed US$10. 2. Bulletin-board services: You may post this archive freely for the downloading convenience of your customers. You may add a comment to the archive promoting your BBS. Please inform me if you do this. You may use Sonarc to compress any sound files in your possession and offer the Sonarc-compressed files for downloading by your customers as long as doing so does not violate any copyrights. Please inform me if you do this. 3. All other organizations (for-profit, not-for-profit, or governmental): After an evaluation period not to exceed 120 days, your organization must either license the software from Speech Compression or destroy all copies in its possession. For its internal use only, the organization must obtain a Site License. For use in distributed products, the organization must obtain a Distribution License. These are available from the contact address below. 4. Individuals (not including fictitious persons, such as corporations): You may use Sonarc in any way you want for as long as you want, as long as it's not-for-profit. This software is being distributed as shareware, i.e., "try before you buy." You may make copies of this archive and distribute it freely or upload it to BBS's. You are required to keep the component files of this archive together, unmodified. You are cordially invited to send in a registration fee of $20 if you find this software useful. In exchange, you will receive one free upgrade of the next version of Sonarc (v2.2 with a "lossy" algorithm) when it becomes available. You will also get the satisfaction of paying for value received. Please send your check made out to "Speech Compression", along with your name and address (if not already imprinted on the check), to: Speech Compression 1910 W. Pawnee Lane Colbert, WA 99005-9401 SONARC version 2.1h Copyright 1994 Speech Compression Page 7 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ OTHER LICENSABLE MODULES: SONLIB.DLL A DLL version of the SONARCX.EXE utility is also available for licensing. This DLL is useful for applications which install under Windows and use lots of WAVE files. It is described in detail below. It is available for licensing by contacting Speech Compression at the address on the previous page. The SONLIB.DLL library has just a single callable function at index 1. The "C" calling interface is as follows: extern int far pascal sonarcx(char* infyl, char* outfyl, int EraseInputFile, int ShowNames); or, in Pascal, function sonarcx(infyl, outfyl: pchar; EraseInputFile, ShowNames: Boolean): integer; far; external; The type "pchar" is a Borland extension to Pascal which is a pointer to a C-style, null-terminated string. The first argument, infyl, may be wildcarded, in which case the second argument, outfyl, should be the empty string '' or a destination path. The third argument, EraseInputFile, has the same effect as the "-D" option in the SONARCX utility, that is, it causes the input file to be erased after successful completion. The fourth argument, ShowNames, has the inverse effect of the "-Q" option in SONARCX. If false, no screen I/O occurs whatsoever. If true, however, it writes the name of the file currently being decompressed in an area of the DLL caller's active window. SONARC version 2.1h Copyright 1994 Speech Compression Page 8 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ OTHER LICENSABLE MODULES: SONLIB.DLL (cont.) The function result is 0 if there were no errors detected. The following are the error codes and conditions that may be returned: -17 16-bit file encounted by a DLL configured to process only 8-bits. -16 .WV file was produced by a later version of Sonarc than v2.1. -15 specify output file name different from input file name. -14 bad block type in .VC file. -13 corrupted VC format file header. -12 input file is not a Sonarc-compressed file. -11 input file is an uncompressed VOC file. -10 internal error: corrupted frame data. -9 version mismatch: compressed VOC file is obsolete version. -8 unknown chunk type in data list. -7 internal error: mismatch in sample count. -6 missing "fact" chunk. -5 "fact" chunk has corrupted length field. -3 WAVE file is already in uncompressed format. -2 WAVE file already compressed using another vendorÆs process. -1 internal error: bad frame checksum (corrupted frame). 2 File not found. 3 Non-existent drive, sub-directory or badly formed file name. 5 Name is directory or existing read-only file. 100 Attempt to read past end of file: probably corrupted sound file. 101 Disk full. 150 Disk is write-protected. 152 Drive not ready. 162 Hardware failure. Other error codes may be returned from DOS for various I/O operations. SONARC version 2.1h Copyright 1994 Speech Compression Page 9 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ OTHER LICENSABLE MODULES: LINKABLE OBJECTS There are also assembly-coded buffer-to-buffer compression and decompression routines available which are highly optimized for both space and speed. The interfaces for these routines are described in detail below. Organizations wishing to obtain copies of these linkable modules must contact Speech Compression at the address on page 6. The "C" declarations for the 8- and 16-bit compression routines are: typedef unsigned char[max_buf_len]* p_bytary; extern int far pascal cmp8(p_bytary p_input, int in_size, p_bytary p_output, int out_max, int order); typedef int[max_buf_len]* p_intary; extern int far pascal cmp16(p_intary p_input, int in_size, p_intary p_output, int out_max, int order); The corresponding Pascal declarations are: type bytary = array [0..max_buf_len-1] of char; p_bytary = ^bytary; function cmp8(p_input: p_bytary; in_size: integer; p_output: p_bytary; out_max, order: integer; ): integer; far; external; type intary = array [0..max_buf_len-1] of integer; p_intary = ^intary; function cmp16(p_input: p_intary; in_size: integer; p_output: p_intary; out_max, order: integer; ): integer; far; external; Both cmp8 and cmp16 take a buffer of order+in_size samples at p_input and compress the in_size samples beginning at p_input[order] into the output buffer at p_output, not to exceed out_max bytes. Note that for cmp16, the size of the input buffer is 2*(order+in_size) bytes, since each sample is 2 bytes. Both p_input and p_output are far, i.e., 32-bit, segmented pointers. The argument out_max is the size of the output buffer into which the compressed frame is copied. Note that this is not the size of the compressed frame; that information is stored into the first 16-bit word of the frame itself. The argument out_max is passed to the routine to prevent it from producing a frame larger than the output buffer whose address is passed in. SONARC version 2.1h Copyright 1994 Speech Compression Page 10 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ The function result is returned in the AX register, where most "C" and Pascal compilers expect it. The result value is zero for normal, error-free processing. Two error conditions are possible. If insufficient stack space is allocated, a result of -2 is returned. This occurs if the SP register is less than approximately 2*order+184 at the time of the call to cmp8, or less than 2*order+364 at the time of the call to cmp16. (Note: This is a change from prior versions where enough stack space had to be allocated to copy the entire input buffer.) The second error condition occurs when the number of bytes of output buffer needed for the compressed input buffer exceeds the value of out_max, in which case a result value of -1 is returned. ─────────────────────────────────────────────────────────────────────────── The "C" declarations for the 8- and 16-bit decompression routines are: extern int far pascal dcmp8(p_bytary p_input, p_bytary p_output); extern int far pascal dcmp16(p_intary p_input, p_intary p_output); The corresponding Pascal declarations are: function dcmp8(p_input, p_output: p_bytary ): integer; far; external; function dcmp16(p_input, p_output: p_intary ): integer; far; external; Both dcmp8 and dcmp16 take a compressed frame at p_input and decompress it into the output buffer starting at p_output[order]. The decompression routine gets the order datum from the byte at offset 7 in the input v2.1 compressed frame (see the frame header description in the File and Frame Formats section). As previously explained, the header of the compressed frame contains, at fixed offsets, the lengths needed by the caller and the decompression routine to figure out how much buffer space to allocate and use, respectively. As is the case for the compression routines, the function result is returned in the AX register. The result value is zero for normal, error-free processing. The only error condition, resulting in a returned value of -1, is if the checksum fails. If this error occurs, it means that the input frame has been folded, spindled, and/or mutilated at some point following its creation by the compression routine. Keep in mind that the entire frame must be passed to the decompression routine; partial frames cannot be decompressed. Note that stack overflow is not checked for in the decompression modules. However, the stack space required by these routines is guaranteed to be less than 50 bytes. The DS, SS, CS, BP, SI and DI registers are preserved by these routines. No instructions unique to the '186, '286, '386, or '486 processors are used in the 8-bit modules. The 16-bit modules, however, make use of the '386 instruction family whenever they "sense" that they are running on a '386 or better. SONARC version 2.1h Copyright 1994 Speech Compression Page 11 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ POSTSCRIPT I picked the d.b.a. "Speech Compression" in 1992, when I started working on a technology for PCs capable of compressing speech signals lossily at ratios of over 10:1. Currently no compression is available for speech at such ratios (of any quality, that is) that does not require either huge run-time tables (>100 Kbytes), or some sort of special hardware support, such as a DSP chip. I got ZipTalk (as I called it) developed to the point where I could prove to myself that decompression of speech signals could be accomplished on an 8088 processor running at 4.77 MHertz with processor to spare, using tables of probably not much more than 16K bytes. The compression side is a complex, but solved, problem since it piggy-backs off of linear-predictive analysis. In fact, the whole trick is to transform frequency-domain parameters obtained through LPC techniques into a special format that I have discovered, which then permits real-time conversion back into time-domain signals. (I can say it faster than I can develop it!) However, while waiting for some research documents to arrive by USnail, I was put in contact with a company which needed lossless audio compression, and I diverted my energy to the development of Sonarc. (If you need Sonarc to be an acronym of something, and you don't like "SOuNd ARChival" then I suppose it could be "Some Outfit Nagged About Reversible Compression".) I've spent a considerable amount of time researching various ways of doing "lossy" audio compression. Earlier versions of Sonarc featured a "lossy" parameter -Ln[n], which achieved higher compression ratios while keeping the total amplitude distortion in the decompressed signal less than n.[n]%. Unfortunately, the compression phase was extremely compute-intensive and generally required overnight runs to compress any significant amount of audio files. I've never tried combining this "lossy" with the -x and -o0 options; I suspect there would be a measurable amount of proton decay before it could finish. I only left it out of this shareware version because it is so slow, and I didn't want that sullying Sonarc's otherwise fine reputation. I'm still developing the "lossy" algorithm, though, and I'll have a "lossy" solution in the v2.2. Don't ask me when; it'll be ready when it's ready. I suppose, in retrospect, I might have called myself "Sound Compression" or some such (not being particularly imaginative in the naming department). But I'm stuck with "Speech Compression", even though I now do general audio compression, and may later branch out into image compression as well. (Most algorithms which process 1-D signals can, in principle, be extended to process 2-D signals.) Send feedback to 76635,3652@compuserve.com. Richard P. Sprague