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DISCPLAY.DOC
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Text File
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1991-06-11
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8KB
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157 lines
~~~~~~~~~~~~~~~~~~~~~
>> The Disc Player << 23/05/91
~~~~~~~~~~~~~~~~~~~~~ ©1991 C. Midgley
Information file for 'Discplayer' Ver: 2.45
Here is a tiny program that replays sound samples with a
difference. If you have a 520 then this program is for you! A
standard half megabyte ST has about 390K or less to load and
replay sound samples. Now, you can replay samples up to an
incredible 910K! Impossible I hear you say, not any more! All you
need is a doubled sided disc drive.......
>> Program requirements <<
ST Computer, colour or monochrome monitor, double sided disc drive
either as drive A or B. Some ST-Replay compatible sound files..
>> All you need to do... <<
1) Format a disc double sided, with the desktop or your
favourite formatting program (i.e. Fastcopy III...) You can use
as many sectors and tracks as your disc drive allows.
2) Copy your favourite sound samples to this freshly formatted
disc so that it is full. Only ST-Replay compatible .SPL files
will work, PRO-Sound Designer's .SAM files are suitable and so
are one or two others. ALL THE FILES MUST BE THE SAME KHz
SPEED! Fade each sample in and out using your sampler software,
it makes the whole thing sound a lot nicer!
3) Load DISCPLAY.TOS and select the replay speed. Press F1 or
F2 depending on which drive you are playing the samples from,
and choose the output device, YM-2149 is the sound chip or Pro
Sound Designer and ST-Replay sampler cartridges. That's all
there is to it! The program will read the data off the disc and
play it using less than 30KBytes of memory!!
'Discplayer' now supports both old and new ST-Replay frequencies
up to 11KHz. Unfortunately 11KHz is, in fact 10 and-a-bit. There
isn't enough processor time to read data and play it at and above
this speed, so 11KHz may not work on every ST due to this very
tight timing limit. You will know if your ST can't cope because
the sample will 'break' every second or so. If this happens to
you, try and format discs with skewed sectors or otherwise known
as twisted and fast format. If you are using Fastcopy III to
format discs, select FORMAT DESTINATION by pressing the 'q' key.
FAST FORMAT DEST. does not work with 'discplayer' on my ST at all,
so best avoid it.
>> Alternate drives option... <<
Pressing F3 will cause the computer to alternate from A to B
drives, playing all the samples on each disc, needless to say, you
will have to have two double sided drives...... Now up to (and
over) 3 Minutes of samples can be played continuously!
>> Disc formatting... <<
You can format your discs to any amount, the maximum amount I can
get from my disc drives is 11 sectors 83 tracks. (about 910K.)
Please note that not all disc drives can cope with 11 sector
formats.
N.B. DON'T delete samples off your discs and copy another one back
to it. This is because you will probably end up with a fragmented
disc, and will not sound correct when played back. You will have
to reformat it and copy the files back.
This sounds a bit of a hassle, but is necessary because of the way
the program works. To obtain the data transfer speed it has to
read the data from track 1 to the last track on the discs. It
never actually reads the directory entries just the actual data
held on the disc. Therefore, if you delete a file and play the
disc back the file will still be played!
Confused? The best way to understand it - is to EXPERIMENT!
>> Using 'Simulated Stereo' <<
If you have ST-Replay or Pro Sound designer you can try this. It
works by playing the standard sound chip 200 bytes ahead of either
Replay or Pro Sound whichever you have selected. This creates
quite a nice effect and makes some samples sound a lot better! You
will need to make up a lead - something like this should do:-
Stereo Amplifier
Atari ST (Monitor Socket.) Pin 1 --------R1------------- Right Channel
Pin 13 --
\____________________ Ground
/
Ground --
Pro Sound/ST-Replay (OUTPUT) Core --------R2------------- Left Channel
R1 & R2 are variable resistors. I needed them because the ST's
output was higher than Pro sound and so one side was louder than
the other. 500Ω linear resistor should be about right. It does not
matter if the left and right channels are connected the other way
round.
>> General Information... <<
You may notice some clicks when the disc drive moves to the next
track. This is to do with a piece of critical timed code that
isn't been run fast enough, I'm trying to find a way of improving
this. It is only really noticeable using Simulated Stereo with
samples containing high pitched frequencies. If a disc error
occurs while the sample is being played, then the program will
drop back to the initial menu.
>> Last word... <<
This program is really only useful to 520 and 1040 owners with one
or two double sided disc drives. But should work on any ST.
'Discplayer' is FREEWARE and remains ©1991 C. Midgley. You may
copy the program only if this file and DISCPLAY.TOS are included
and that nothing is modified in ANY way. Use this program at your
own risk - don't blame me if it misbehaves... A special 'thank
you' must go to Robert Pemberton, as without his time and effort
teaching me assembly, I would still be programming in Fast Basic!
(Ugh!!) This is my first attempt at writing something challenging
in assembly language. After spending a Sunday afternoon
disassembling a P.D. sample replay routine to find out how samples
were actually played back, I had this great idea - and here it is!
I like to write programs as efficiently as possible, (who said
programmers are a greedy lot...) if you disassemble it - I don't
think you could find a way to make it much smaller. That's why
this program is'nt flash with pretty graphics etc.. If you would
like the source code (this is heavily commented - even my hamster
can understand it....) then send a disc to the same address not
forgetting your own address. All comments, suggestions,
constructive criticisms are of course welcome. Don't forget to
include enough stamps/money for the return of your discs as I'm a
school kid and money does'nt grow on trees you know...
>> New for version 2.45 <<
o Bug Fixes. ( Yes, it will now play discs with any track
length!) In fact its now totally optimised and bug free (I
think...).
o Display of current track been played.
o The VBL has now been turned off during sample replay.
I had to do this because I needed more processor time.
o You can now choose between three output devices.
o Improved 'Simulated Stereo'. Now 200 bytes shift.
>> Future versions. <<
1) Hard disc support. If I ever get a hard disc that is......
2) STE support.
Please Robert, can I borrow your STE? (Need I say more?)
Chris Midgley, 4 Westgate, Guiseley, Leeds, LS20 8HL, England, Earth.