HPAVC/HPAVC CD-ROM.iso/C2SND201.ZIP/SND2WAV.DOC

Text File | 1994-09-11 | 21KB | 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
  [phone]
  Internet:  [e-mail]

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 ([e-mail])