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1995-02-25
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-- Play16 version 1.3a (24.02.95) - a versatile soundplayer for the Amiga --
Features in brief
-----------------
- autodetects and plays several soundfiles, up to 16 bit / 56 kHz / stereo
- always correct playback speed, even for sounds >28 kHz
- realtime playback from harddisk, optimized assembler routines
- optional 14 bit output (less noise but not as good as true 16 bit)
- automatic or manual audio filter control
- plays mono sounds on *both* channels, not only on the left one
- plays (and loops) files that are larger than memory
- preloading for exactly timed start of playback
- fast uLaw decompression
- system friendly audio channel allocation
- supported Filetypes are:
* Microsoft RIFF-WAVE (.WAV) mono / stereo, 8 / 16 bit, linear / uLaw
* Sun/NeXT Audio (.AU) mono / stereo, 8 / 16 bit, linear / uLaw
* MacroSystem MAUD (.MAUD) mono / stereo, 8 / 16 bit, linear
* Apple/SGI/Amiga AIFF (.AIFF) mono / stereo, 8 / 16 bit, linear
* Amiga IFF-8SVX (.IFF) mono / stereo, 8 bit, linear
* Any raw sound data as long as it matches one of the following:
- 8 bit signed
- 8 bit unsigned
- 16 bit signed, Intel format (LSB first)
- 16 bit signed, Motorola format (MSB first)
What do I need to use Play16?
-----------------------------
Any Amiga running Kickstart/Workbench 2.04 or greater.
Where do I find the latest version?
-----------------------------------
- FIDONET: Amiga Venture BBS, Germany (2:243/6050)
- AmiNET: mus/play
What does it do?
----------------
Basically, Play16 is capable of playing uncompressed and _some_ compressed
soundfiles through Amiga's standard audio device. If the actual resolution
or playback rate exceeds that of the Amiga hardware, realtime conversion
is done so that the sound is being played back correctly.
You can even play 16 bit / 44.1 kHz sounds, providing all parts of
your system can keep up with the high data transfer rate and lots
of calculations needed for this task. (In this case an accelerated
Amiga is recommended :-)
The two audio channels at each side can be linked to perform as a single
14 bit channel. Again, this swallows lots of computing power.
Anyway, my Amiga 3000-16MHz is fast enough to play an uncompressed soundfile
with full 44.1kHz/14bit output (productivity) directly from harddisk !!!
I don't want Play16 to be a program that plays each and every exotic format
that exists somewhere. However, I intend to support as many popular file
types as possible.
How do I use it?
----------------
Simply type "Play16 <filename>" and that's it!
All possible options will be explained later. If you set none of them, the
defaults will be used.
Why Play16?
-----------
16 bit soundcards are becoming more and more popular, especially on the
PC. The common file format over there is Microsoft's (yuck! :)) RIFF-
WAVE format.
I didn't find any CLI based program to play back 16 bit recordings, on a
standard Amiga, so I decided to write one myself.
Why CLI based and no GUI?
-------------------------
There are so many GUI based directory utilities, simply use Play16 as an
external player. Consult the manual of your software package on how to
do it. Application example: Assign "Play16 <filename> PRELOAD" to a button
called "Jingle". Select the desired soundfile and press the Jingle-button.
Wait for the appropriate moment and hit the return key - here comes the
sound! Nice when audio dubbing your home videos or even on parties :-)
How does it work? (technical info)
----------------------------------
The standard Amiga audio device is limited to 8 bit / 28 kHz playbck
when using DMA. With the introduction of ECS the 28 kHz DMA barrier
was broken - but only if the current displaymode was one with double
scan rate like productivity. The reason for this is the dependency
between video and audio DMA. If you don't have ECS or if you simply
don't want to switch to Productivity just to listen to your desired
sound, Play16 can halve the sample rate during playback.
Another way to archieve high output rates is using IRQ. This works no
matter what the displaymode is. I've been experimenting on that long
before I started writing Play16 but there was so much jitter that my
current downsampling method sounds much better.
To play back even long sounds, the popular method of double buffering
is used. Alternatively, all data can be loaded into memory before
playback. This is useful when playing short sounds or when loading
the sound from floppy disk or slow CD ROM.
The 14 bit output is archieved by setting the first channel on each
side to volume 64 and the second to volume 1. The louder channel then
plays the upper 8 bits as usual while the other channel plays the
6 most significant bits of the low byte synchronously. Because timing
is very crucial in this case it is nessecary to write directly to
hardware registers instead of using the audio.device. This method may
not work on future amiga models if there ever will be any... :-/
What options are provided?
--------------------------
If you are not familiar with the AmigaOS 2.x commandline template, see
the examples below and consult the AmigaOS manual for furhter information.
FAST/S Do not automatically switch to half sample rate if the
soundfile's rate exceeds 28 kHz. Use this option when
running your Amiga in Productivity or similar display
modes.
HIFI/S Turn on the 14 bit output. Watch out! This is a nasty routine
that writes directly to some hardware registers. I've done
everything I can to prevent Play16 from interfering with
other running tasks in this case but you'll never know...
Use it with care!
FILTER/K FILTER=ON : Enable audio filter for playback
FILTER=OFF : Disable audio filter for playback
FILTER=AUTO: Turn filter on or off depending on sample rate
If you don't specify this keyword Play16 will leave the
hardware registers of the audiofilter completely untouched.
SINGLE/S Use only one buffer rather then two and load all data into
memory befor playback.
BUFFER/N Buffersize in samples. May vary from 32768 to 131072. The
amount of allocated memory also depends on whether the sound
is mono or stereo, 8 bit or 16 bit.
Default is 65536 samples, values are rounded to multiples of
32768.
Note that it is useless to modify this value when in single
buffer mode :)
VERBOSITY/N Sets the level of verbosity.
0: Just display the banner and error messages
1: Print additional information about the sound file,
allocated memory, etc.
2: Progress information
3: Debugging information (may look a bit weird :)
Default is level 0.
LOOPS/N Determines the number of loops to be played.
Default is 1 loop. (Play the sound once.)
This option is not yet supported in SINGLE mode.
PRELOAD/S Load enough data into memory for immediate start of playback
at a keypress
RAW/S Disable autodetect and tell Play16 what the actual format of
the sound data is.
However, if Play16 can't detect the filetype it will switch
to RAW mode automatically. If you don't want this to happen
you can specify...
STRICT/S Play only files that are supported by the autodetect routine
Use this if you don't want to be scared by the sudden noisy
output when trying to play back other data than sound :-)
The following options tell Play16 what parameters to use when in RAW mode.
This happens either if you set the RAW keyword or if Play16 could not
identify the file and STRICT was _not_ set.
FREQ/N Sampling frequency in Hz
TRACKS/N Number of tracks, 1 for mono, 2 for stereo
BITS/N Resolution in bits, may be 8 or 16
HEADER/N Length of header: This is the number of bytes to be skipped
at the beginning of the file.
UNSIGNED/S Data is unsigned, not signed (only valid for 8 bit sounds)
INTEL/S Data is in Intel format (only valid for 16 bit sounds)
ULAW/S Data is compressed using the uLaw compression scheme
The default settings are: 22050 Hz, mono, 8 bits, no header.
Examples:
a) Play16 music.wav
Simply play the file called music.wav once and directly from harddisk.
b) Play16 music.wav SINGLE
Same as above but load all data into memory before playback. Use this
when loading soundfiles from floppy disk.
c) Play16 music.wav SINGLE VERBOSITY=1
Same as b, but with additional information being printed out.
d) Play16 rhythm.wav LOOPS=10
Play the rhythm as a continuous loop, i.e. over and over again (10 times)
e) Play16 explosion.wav SINGLE PRELOAD
Load the complete explosion sound into memory, then wait for you to hit
<return> before playback.
How do I use this RAW mode?
---------------------------
Umm, err, difficult to explain, even harder to understand...
Well, if you know the data format of the soundfile, simply set RAW, FREQ,
TRACKS, BITS, UNSIGNED and INTEL accordingly. If you don't, the only
way to find it out is by trial and error :) Here are some tips to make
it a bit easier:
Don't set HEADER to an odd number. (Leave it at 0, first.)
If you set BITS to 16 and hear nothing but noise, try to set INTEL.
If you set BITS to 8 and the sound is distorted, try to set UNSIGNED.
If the above does not help, try different combinations of BITS, INTEL
and UNSIGNED.
If you manage to get a recognisable sound output which is either too
fast or too slow, start experimenting on TRACKS and FREQ.
If you want to play known files and raw ones without changing the command
line, simply specify all you know about the raw data and leave out the
RAW and the STRICT keyword. If Play16 can indentify the file it will use
its parameters. If the filetype is unknown your specified parameters will
be used instead.
Legal stuff
-----------
Play16 is copyrighted freeware. It may be distributed freely as long as
no modifications are made to the executable and this document. A nominal
fee may be asked to cover distribution costs.
Play16 may not be used for any commercial purposes or included with any
commercial product without the written permission of the author.
No responsibilities are taken for damaged speakers, amplifiers, Amigas
or any other components or data involved while using Play16.
Although I've done some beta testing I can't guarantee that Play16 will
not crash! If you find any bugs, let me know.
Miscellaneous
-------------
I don't claim Play16 to be fast. I've done some optimizing - but because
the loader/converter module is a universial one, more data is actually
being moved around different memory blocks than needed for playback.
I've implemented separate optimized routines for 8 bit and 14/16 bit.
This method will provide the basis for future enhancements in the playback
routine like soundcard support.
* Please note that English is not my native language :)
I can be reached at...
Internet: wenzel@unixserv.rz.fh-hannover.de (preferred)
Thomas_Wenzel@aventure.fido.de
Fido: 2:243/6050.28 or 2:241/1035.6
Mail routing _is_sometimes_ unreliable in FidoNet :-(
If you use this program, please send me a mail. I'd like to know how many
people are interested in it at all.
History
-------
V0.5▀ - Initial beta test release
V0.6▀ - Optimized the code a bit.
V0.7▀ - Fixed some severe bugs that caused Play16 to crash when trying
to load corrupted files.
V0.8▀ - Play16 can now be stopped by pressing ctrl-c during playback. The
buffer that is currently being played will be finished first.
- Automatic filter control depending on sample rate.
V0.9▀ - Added 'loop'-option. Sample can be played several times.
- All time consuming routines now in hand optimized assembler code.
V1.0▀ - Play16 now uses standard OS2.x commandline template.
Thanks to Kai for persuading me to do this :)
V1.0 - Done some minor bugfixes.
V1.1 - Oops! Play16 caused some Enforcer hits. Fixed that.
Thanks to Rod Schnell for reporting it.
- Added 'single'-option. Sound can be loaded completely into memory
before playing. No looping possible in this case yet!
- Playback time in minutes:seconds displayed if verbose >= 1
- uLaw decompression for WAVE-Files, using a decoding table
for maximum speed (didn't do much testing on it, hope it works!)
- MAUD filetype support (why do there have to be so many formats?)
- AIFF filetype support
- ctrl-c now stops playback immediately.
Thanks to Marc for some programming tips about that.
V1.2 - IFF-8SVX filetype support (only uncompressed files!)
- RAW data support: _Any_ data can be played
- Preload feature added
- Fixed a bug that caused illegal memory access (hopefully)
Thanks to Ignatios Souvatzis for reporting it.
- Improved chunk handling
V1.3 - 14 bit output (finally!)
- Any file Play16 can't recognise is considered raw data unless
you set the STRICT keyword
- Fixed a bug in WAV filetype length determination
- Advanced audiofilter control / original state will be restored
after playback
- More information about sound (AUTHOR or ANNO-Chunk) is being
printed out if VERBOSE>=1. However, Play16 will *not* search
the whole file for that string. If it doesn't come before the
sound data -- bad luck :-)
V1.3a - Bugfix in chunk handling routine: Chunks with an odd length
were treated incorrectly. This bug accompanied all versions
of Play16, even V1.0. However, I decided to release a fix now
instead of letting you wait until V1.4 is finished.
Future plans
------------
- Wildcard support (!)
- Filerequester if no filename is given
- Workbench icon with tooltype entries
- Settings can be stored in environment variables
(especially useful for filter setting)
- Stop playing by ctrl-c _or_ lmb (probably by clicking on a gadget)
- other uLaw-formats and almost certainly Creative-VOC support
- Samplitude HDPs and RAPs
- Letting Play16 open a productivity screen for fast DMA
- ADPCM decompression (still having difficulties coding the algorhytm)
- some of the file types saved by Macintosh software (e.g. Sound-Designer)
- Soundcard support
Known bugs
----------
Some files have additional information stored AFTER the waveform data.
Play16 does not recognise that and tries to play the data, resulting
in a short 'blip' at the end of the sound. So far I've only encountered
*some* WAVs that have this additional chunk at the end of the file.
Credits
-------
Thanks go to the following persons:
Kai Stuke for many vital hints on C programming and the Amiga
audio device.
for beta testing this program.
Marc Fⁿhrer for doing some beta testing as well.
for some hints on optimizing the code.
Clete Baker for supplying the AIFF- and SDII specs.
And to all the people who wrote me!