HPAVC

home *** CD-ROM | disk | FTP | other *** search

/ HPAVC / HPAVC CD-ROM.iso / pc / C2SND201.ZIP / SND2WAV.DOC < prev next >

Wrap

Text File | 1994-09-11 | 20.5 KB | 493 lines

Snd2wav: Converter for Tandy DeskMate .snd Files ------------------------------------------------- Version 1.1 Written by: Jeffrey L. Hayes 130 Forest Ave., Lot 1 Orono, Me. 04473 (207) 866-7903 Internet: tvdog@delphi.com This program is in the public domain. Contents: 1. Purpose 2. How to Use Snd2wav 3. Possible Problems 4. About .snd Files 5. Other Programs for the Tandy Sound Chip 1. Purpose This is a companion program to Kenneth Udut's Conv2snd program for converting .wav and other formats to .snd. I did the revisions for version 2.00 of that program. This program converts DeskMate .snd files to RIFF WAVE format, allowing them to be played without the DeskMate Sound.pdm program. This allows sounds edited with Sound.pdm to be shared with users on non-Tandy machines. Version 1.1 now supports the new-format .snd files used on the 2500- series. 2. How to Use Snd2wav The simplest way to use Snd2wav is just to type its name: snd2wav The program will prompt you for the input filename (i.e., the .snd file). The filename may include drive and/or path. If you do not specify an extension, it defaults to ".snd". You may specify a file without an extension by ending the filename with a period. The output filename will be the same as the input filename you specify, including drive and/or path, but with a ".wav" extension. You can also specify the input file on the command line: snd2wav a:\sounds\scream The above will convert a:\sounds\scream.snd to a:\sounds\scream.wav (and possibly more - see below). Or you can specify both the input and output filenames: snd2wav c:oldsnd.snd \newsnd. The above will convert file "oldsnd.snd" in the current directory of drive C: and place the result in the root directory of the current drive as "newsnd" (without an extension). If all goes well, you will see something like the following: C:>snd2wav spockd Snd2wav, v. 1.1: DeskMate .snd to RIFF WAVE conversion program. Converting: spockd.snd Creating: spockd.wav Conversion complete. Thank you for using Snd2wav. You may also see this if you convert an instrument file with more than one note defined: I:\CONV2SND>snd2wav piano new Snd2wav, v. 1.1: DeskMate .snd to RIFF WAVE conversion program. Converting: piano.snd Creating: new.wav Creating: new2.wav Creating: new3.wav Conversion complete. Thank you for using Snd2wav. If the .snd is an instrument file with more than one note defined, Snd2wav converts each note to a separate .wav file, as above. There can be up to 16 notes in an .snd file. Snd2wav will generate new names from the original output filename as necessary by appending a digit, as above. The "digits" for the 10th through the 16th notes are letters "A" through "G". If the output filename is already 8 characters long, the last character will be overwritten by the digit: I:\CONV2SND>snd2wav cello longname. Snd2wav, v. 1.1: DeskMate .snd to RIFF WAVE conversion program. Converting: cello.snd Creating: longname. Creating: longnam2. Creating: longnam3. Conversion complete. Thank you for using Snd2wav. That's it. The output file is a valid .wav file playable on any machine with a .wav player. 3. Possible Problems If something goes wrong during the conversion, Snd2wav will do its best to tell you what it thinks the problem was, and what you should do about it. Its word should not be taken as gospel, however; it's just making its best guess about the probable cause of something that may have many possible causes. One error message that you are certain to see if you run out and try to convert the .snd files that came with DeskMate is the following: I:\CONV2SND>snd2wav h:piano.snd i:piano Snd2wav, v. 1.1: DeskMate .snd to RIFF WAVE conversion program. The input file you specified: h:piano.snd ... is compressed. Snd2wav can't convert compressed .snd's. Load the file into Sound.pdm, turn compression off, and resave the file. Then try again. You can convert piano.snd if you follow those directions. Compressed .snd's, as the message says, can't be converted. I don't know the compression algorithms used by Tandy, so this program can't interpret compressed sound data. Here is something else you might see: I:\CONV2SND>snd2wav piano b:piano Snd2wav, v. 1.1: DeskMate .snd to RIFF WAVE conversion program. Converting: piano.snd Unable to create file b:piano.wav. Either the name is not a valid filename, or the disk is write-protected, or there is already a read-only file with that name. Check the filename and unprotect the disk, then try again. In this case, I have a write-protected disk in drive B:. I have to remove the write-protection before I can write files on B:. Here is another that might be pretty common: I:\CONV2SND>snd2wav nosound Snd2wav, v. 1.1: DeskMate .snd to RIFF WAVE conversion program. Converting: nosound.snd Note number 1 of the input .snd file contains no samples. The .snd file was saved after a note was created but before sound was recorded for the note, or the .snd file is a new sound file with no data recorded into it. This note is being skipped. Conversion complete. Thank you for using Snd2wav. I'm trying to convert a file with no sound in it. What I did was start Sound.pdm without loading a data file, then "Save as ...". Note the "Conversion complete" message: Snd2wav does not consider this an error. There just isn't any sound to convert, so there isn't any output .wav created. The "Note number 1" might throw you if you haven't dealt with instrument files. Instrument files can contain several different sound samples for different musical notes. When it's converting an instrument file, Snd2wav makes a different .wav file for each note. The easiest way for me to do that sort of thing was to treat sound files as if they were instrument files with one note. In the above example, nosound.snd is a sound file that has nothing recorded into it. If I had an instrument file with something recorded into some notes but not others, I would have seen the message above for the unrecorded notes, but the recorded notes would have been converted correctly: I:\CONV2SND>snd2wav cello Snd2wav, v. 1.1: DeskMate .snd to RIFF WAVE conversion program. Converting: cello.snd Creating: cello.wav Creating: cello2.wav Note number 3 of the input .snd file contains no samples. The .snd file was saved after a note was created but before sound was recorded for the note, or the .snd file is a new sound file with no data recorded into it. This note is being skipped. Conversion complete. Thank you for using Snd2wav. Finally, here is an error you are likely to see if you make misteaks when you type, like I do: I:\CONV2SND>snd2wav celo Snd2wav, v. 1.1: DeskMate .snd to RIFF WAVE conversion program. File celo.snd does not exist. Check the filename and try again. One known *BUG* in this program is that it won't convert read-only .snd files, insisting that they "do not exist." This is a bug in the Turbo Pascal runtime library, and I don't have any immediate plans to fix it. The bug applies only to files made read-only with the Attrib +r command, not to files on a write-protected floppy disk. Use Attrib -r to unprotect your .snd file before you convert it (Snd2wav does not modify the .snd file). There are several other, less common, error messages you can get. What you should never see is a message like this: Runtime error 200 at 0000:1A3E. This type of error message indicates that I made a mistake in writing the program. If you get a message like this, I need to know about it so I can fix the problem in the next version of Snd2wav. You can reach me by phone, by U.S. mail, or by email, whatever is convenient. Be sure to write down the message so you can tell me what it says. See the top of this file to find out how to reach me. If you get any kind of error message you don't understand, call or write me and we will try to figure it out. For use in batch files, Snd2wav will return errorlevel 1 if anything goes wrong during the conversion, or errorlevel 0 if all is OK. 4. About .snd Files The following is provided for the benefit of those who may wish to create other programs using the Tandy DeskMate .snd format. You do not need to know anything in this section to use this program. There are two types of DeskMate .snd files, sound files and instrument files. Both contain 8-bit unsigned PCM samples. "PCM" stands for "pulse code modulation" and just means that the sound wave is sampled at fixed intervals and its level recorded. It's just like you used to do in high school algebra when you were asked to graph a function by evaluating it at various points. With Tandy PCM, the samples are integers in the range 0-255. Sound files are the simpler of the two types of .snd files. These are garden-variety sample files with a fixed-length header giving the name of the sound, the recording frequency, and the length of the sound. Sound files may be recorded at 5500Hz, 11kHz or 22kHz. Instrument files contain samples as well as frequency and looping information used by Music.pdm to represent an instrument. Instrument files provide for attack, sustain, and decay with several samples having different implied frequencies and being used by Music.pdm to represent the instrument in different pitch ranges. Up to 16 different notes (with 16 different samples) can be contained in one instrument file. Instrument files are always recorded at 11kHz. Snd2wav discards the extra information when converting instrument files, only extracting the note samples themselves. There is no standard place in the .wav format to put the extra information (it could conceivably go in an INFO chunk, but Snd2wav doesn't do that). Both sound files and instrument files may be compressed in one of two ways, "music" compression or "speech" compression, or they may be uncompressed. I don't know the compression algorithms, but simple file comparison reveals that "music" and "speech" compression are almost identical. The old-format DeskMate .snd file header consists of 16 bytes of fixed header information followed by one or more 28-byte note records. The sample information, which may be compressed, follows the header. The new-format .snd file header, used on the 2500-series, consists of 114 bytes of fixed header followed by one or more 46-byte note records; it contains essentially the same information as the old header. Conv2snd creates old-format .snd files; the 2500's can read the old format. Many of the numbers below are given in hexadecimal, or base-16 notation. Hexadecimal is a common way to express numbers when programming at the machine level. In base-16, letters A through F are used to represent "digits" 10 through 15. Also: "word" is a 16-bit unsigned integer, and "dword" is a 32-bit unsigned integer. "American Standard Pitch" refers to the sound frequencies assigned to the various musical notes by the American Standards Association. Sound frequencies are based on A above middle C being 440 cycles per second. This A is called A4. An octave below that is A3, an octave above, A5. The frequency doubles with each octave increase in pitch. Sound.pdm does not display standard notes to you, though. Standard octaves begin at C, so you would have A#2, B2, C3. Sound.pdm starts its octaves at A. The sampling rate has nothing to do with the pitch frequency, except that the rate must be at least twice as high as the highest frequency you want to record. DeskMate .snd File Format - Fixed Header ---------------------------------------- offset size what ------ ---- ---- 0 byte 1Ah (.snd ID byte). Note that 1Ah = <cntrl>-Z, so if a user attempts to type the .snd file to the screen, nothing will be displayed. 1 byte Compression code: 0 = no compression; 1 = music compression; 2 = speech compression. 2 byte Number of notes in the instrument file. 1 if sound file. There can be up to 16 notes in an instrument file. Note: when an instrument file is created, it automatically has one unset note placed in it. 3 byte Instrument number. 0 if sound file; 0FFh if instrument file with no number set. Valid instrument numbers in an instrument file are 1 to 32. Use this field to distinguish a sound file from an instrument file. 4 10 bytes Sound or instrument name. Name is a null-terminated string, so there are up to 9 characters of the name, plus the null byte. 0Eh word Sampling rate in samples per second. Note that although a sampling rate other than 5500, 11000 and 22000 can be entered here, Sound.pdm will not actually play at other rates. 10h variable Note records begin, 28 bytes each. Number of records given in byte 2 above. DeskMate .snd File Format - Note Record --------------------------------------- 0 byte Pitch of the note: 1 = A1 in American Standard Pitch; 2 = A#1; etc. A1 is lowest note allowed; highest note allowed is B6 (3Fh). Sound files have 0FFh here; so do instrument files with no note set. Note that Sound.pdm does not designate notes in the standard manner to the user. Although A1 and B6 in Sound.pdm are the same as A1 and B6 in standard pitch, Sound.pdm starts octaves at A rather than at C (as is standard). Thus, middle C, C4 in standard pitch, is C3 in Sound.pdm. 1 byte Sound files, and instrument files with no pitch set, have 0 here. If the pitch is set, this byte is 0FFh. 2 2 bytes Range of the note, first byte is lower limit, second is higher limit. Byte encoding as for offset 0 (i.e., 01h to 3Fh). Sound files have FF FF here; so do instrument files with no range set. 4 dword Offset in the file where samples for this note begin (zero-relative), after compression if that was done. 8 dword If compressed, the length of the compressed data in the file for this note. Uncompressed files have 0 here. 0Ch 4 bytes Unknown. Set to zero. 10h dword Number of samples in the note, after decompression if necessary. 0 can appear here. 14h dword Number of sample at start of sustain region for the note, relative to the first (zeroth) sample of the note. For sound files, or if sustain is not set, this field is 0. 18h dword Number of sample at end of sustain region for the note, relative to the first (zeroth) sample of the note. For sound files, or if sustain is not set, this field is 0. For new-format files, the header looks like this: New Tandy .snd File Format - Fixed Header ----------------------------------------- offset size what ------ ---- ---- 0 10 bytes Null-terminated sound name. 0Ah 34 bytes Unknown. 2Ch 2 bytes New .snd ID: 1Ah 80h. 2Eh word Number of notes in the file. 30h word Sound (instrument) number. 32h 16 bytes Unknown. 42h word Compression code (0 = no compression, 1 = music compression, 2 = speech compression). 44h 20 bytes Unknown. 58h word Sampling rate in samples per second. 5Ah 24 bytes Unknown. 72h variable Note records begin. Number given by word at 2Eh above. New Tandy .snd File Format - Note Record ---------------------------------------- 0 dword Link to next note record (offset in file of next note record). 0 if last. 4 2 bytes Unknown. 6 byte Pitch of note (01h-3Fh), 01 = A1 in American Standard Pitch; 0FFh if not set. 7 byte Unknown (compare old .snd format; value is 00h or 0FFh, but seemingly unrelated to the pitch setting). 8 2 bytes Range of note. First byte is lower limit, second is higher limit. Values as for byte at offset 6 above; 0FFh 0FFh if not set. 0Ah dword Offset in file of start of sound data for this sample. 0Eh dword Length of sample sound data in bytes. 12h dword Uncompressed length of sound data (number of samples). 16h 24 bytes Unknown. 5. Other Programs for the Tandy Sound Chip There are programs other than Sound.pdm that can record sounds on a Tandy with the proprietary sound. Here are a few of them. All can record and play back sounds of arbitrary length, unlike Sound.pdm. None allows you to edit sounds as Sound.pdm does. The first two are share- ware; the last is free. David Stewart's Sampler package records and plays raw headerless samples at near 11kHz and features voice activation. The registered version purportedly provides keyboard activation (nice because the voice activation seems to have a will of its own) and allows the sampling rate to be varied. Sean Haynes' Tndsound program records and plays sound files in its own proprietary format. The unregistered version of this package does not appear to be crippled. There is a menu-driven interface. This program offers sound filtering and control over the playback volume. Overall, I would say that Tndsound is better than Sampler. One drawback to this program is that it doesn't know how to compute the sampling rate in Hz from the DAC divider value, so it's hard to select a standard sampling rate (you have to specify the rate as a meaningless number). The default rate is around 9kHz. My Tspak package contains a program, Recwav, to record RIFF WAVE files at an arbitrary sampling rate (the default is 11kHz). It runs from the DOS command line. The rate is set in Hz. There is also a program, Playwav, that can play 8- or 16-bit mono or stereo .wav's at up to 65535 Hz. Tspak contains other programs useful to Tandy owners, including one to convert .snd files to Amiga .mod samples for use in a .mod editor, and another to enable the Tandy DAC to be used with some programs that otherwise would not support it. Tspak also comes with source code and programming information if you want to write your own programs for the Tandy sound chip. Sampler and Tndsound are on Delphi in the PC-Compatibles .sig, Crossfire Database. If you are not on Delphi, write me and I'll mail you a copy. Tspak is on Simtel. ftp to: oak.oakland.edu and get file: /pub/msdos/sound/tspak.zip It is also worth noting that there is a Windows 3.1 sound driver for the Tandy DAC, available on some BBS's and from Radio Shack. It will work on the 1000RSX and the 2500-series. Happy listening! Jeff (tvdog@delphi.com)