DOS 2.0 Utilities Disk 10 (Aug 1992) : Arq / Upd.doc

Release 1.00

		The minimal player daemon - upd
		===============================

	© 1991 Jonas Petersson & Absolut Software (aka Sirius Soft)



Introduction:
=============

Wouldn't it be nice to have a process hanging around to play any
sound file for you on demand instead of you having to do all this
mucking about with audio.device etc? But it really has to be small
and it HAS to be able to play my very large samples anytime...
I must be able to call it simply from anywhere - even from scripts!

Tricky, but it can be done.

As a feature you can register you favourite sounds in a configuration
file and well behaved programs will use the ones you like right now.
It also has Arexx support - to be truely honest, that the ONLY way to
use it...

Current version works rather well along the way I intended.


Usage:
======

	[run] upd [bufsize [IDfile]]

The "run" is ofcourse optional, but daemons really should be in the
background unless you want the see the debugging information.  "bufsize"
is the amount of chip memory that each of the four buffers will use
while playing.  (These are allocated at start to make sure you will be
able to play anytime - as long as you can get hold of the audio
channels...).  Default is 1024 and specifying less than 64 will give you
the default. (I've heard that some people can't ever get anything good
out with less than a 1K buffer - am I really the only one with a quick
enough HD/SCSI interface?) 

NOTE: Don't make the buffer bigger than you actually need - a large
buffer also means that the sample will start a little bit later since
more information must be loaded before it can begin!

The if the IDfile parameter exists, it will be used instead of the
default s:upd.IDs. Note that you have to set bufsize explicitly to use
this. I agree that it's a bit ugly but most people should really not 
need to use this.

The above won't produce any sound as you probably realize.  Once run, the
only way to talk to upd is with Arexx - I even removed the BREAK stuff
that was in it for Zound, since Arexx could hang around waiting for a
reply forever when you interupted the sound that way. The break will
"wait" until the daemon is idle next time.

upd currently knows of four commands:

	file filepath [options] [anotherfilepath [options]]
	id   id-in-s:upd.IDs
        rescan new-id-file
	exit

Well, there is actually one more command: 'Can it, Marvin'. This will 
silently interrupt the current sample. (To be truely honest, ANY command
will interrupt a sample - if it's known, it will be used, otherwise the
sound just stops). Be careful with the 'rescan' command, if there is a 
problem reading the new file, you will loose all your old IDs...

The options are the same as for Zound except for the -n option that doesn't
exist here (tell me you need it and I'll fix that too... sigh). Here's the
list:

    -r rate	How fast to play the sample. Default is what is in the
		8svx header or 310 if it's a raw file. This is usually
		reasonable - most 'raw' samples I've come across are either
		310 or 155. Lower numbers will play the sample faster.

    -v volume	Ranges between 0 and 64, 64 being max and default.

    -s start	Possible offset from the beginning. Default 0.
    -l length	Possible length unless you want it all. Default is
		length of the sample. Be careful with these two, or
		you might get undesired results.

    -c cycles	How many times to play each buffer. Default 1. Not
		very useful, but you can get a nice "mouse" effect by
		setting this to 2 and playing twice as fast...

    -d		Show debug information. Note that this will appear on
		the standard output of the DEAMON, not where you called 
		it from (that is, the ARexx script or wherever).

    -L		Play the sample in the left speaker only. If it's a stereo
		sample only the left channel samples are used.
    -R		Same as '-L' but for right speaker.
    -S		Play in both speakers even if it's a mono sample.
		Default for these three options are of course what is in the
		8SVX header or -L if it's a raw sample.


Example of usage (from WShell etc):

	"address play file 'sounds:chopper'
	"address play id 2001
        "address play rescan 'ram:upd.IDs'
	"address play exit

NOTE: Arexx normally converts everything to UPPERCASE and might try to
do arithmetics etc on filenames which is why it's generally a good idea
to 'singelquote' all paths, IDs etc. If you're looking for the port
'the hard way' to send your own message, the name is "PLAY" in uppercase.

NOTE2: If you are REALLY in a hurry to get rid of upd you could do this:
 1) Send a any dummy Arexx message (this will stop the sound)
 2) Send a break C to upd - break still works when upd is idle.
or
 A) Send the exit message.
 
The last might sound much easier than the first unless you (like me)
have a trapped DisplayBeep() that 'pings' via upd.  In this case,
producing a DisplayBeep() and a break C is much simpler.  The order is
not relevant since the break is "queued". 
 

Hints:
======

Running upd from your SOUNDS: directory is a nice way to get rid of having
you type the FULL path everytime you want to play a sample. (The daemon
has no simple way of knowing WHERE you were when you sent the message 
(that I know of) and therefore assumes it to be in the current directory)


Files:
======

	s:upd.IDs

This file contains the IDs of your favourite samples like a database
the is easily editable. File format:


# Lines starting with '#' are comments
# Id list for micro player daemon
# Created 910201 Jonas Petersson (zaphod@magrathea.indic.se)
# These sounds could be called for at certains situation
# On severe error
BUG	sounds:explosion -S
# When asked for confirmation
CONFIRM sounds:PressLeftMouseButton -L
# Minor trouble
ERROR   sounds:ImSorryDaveImAfraidICantDoThat -R
# Going down...
GURU	sounds:RoysDeathMonologueFromBladerunner -S
# Personal shortcuts/favourites
2001    sounds:openpod -L sounds:hal -R


Removing entries will ofcourse result in no sound (upd might mourn about
it on the standard output though, unless you redirect it). Remember that
ARexx might convert to uppercase unless you quote!

Feel free to add whatever you like. Could be nice with some standard though.
Suggestions are welcome. Mjl's Arq is an example of a program that uses
this feature. Read Arq's docs for details.

NOTE: It *IS* possible to have white space, lowercase etc in the IDs, but
it might cause confusion if used. Be warned.

NOTE2: The file is scanned once when the program starts. If you make any
changes to it, you'll have to restart the deamon.


Return codes:
=============

If the Arexx command returns 20, the secondary result code gives the
reason for the failure:

10	Can't allocate channels.
17	Can't open s:upd.IDs on request to play by ID.
18	Requested ID not found.
19	Trouble reading new ID file.
20	Error during parse of options.
21	Can't open file with sample.
22	File is IFF, but not FORM 8SVX.
23	Bad IFF file.
24	Bad CHAN length.
25	Bad VHDR length.
26	Can't open file 2nd time. (For stereo possibility)
30	Can't play backwards. (Wierd options)
31	Can't allocate IOAudio structs.
32	Can't open ports for channels.

Being interrupted to play another sample is not considered a failure.


Future enhancements:
====================

Maybe automatic detach (didn't work well in Aztec 5.0a, and I havn't really
tried with 5.0d yet).

Probably not very much else - this is a simple sound daemon for minor
background purposes of helping simple programs do more than DisplayBeep().
I'd like to think of it as a complement to SPEAK: - if you want more
you probably want it interactive. (Hmm, that's a thought - a SOUND: device)



Problem history: 
================

1. If your sample is on a floppy (or a very slow HD) there might be 
   some sounds of silence when the playing rate exceeds the loading
   rate... 
Fix: You can now specify the amount of memory to be used by upd when you
   start the daemon as in: 'upd 2000'. But note that a larger buffer also
   makes a longer delay until you hear the first part of the sound - it
   doesn't start until it has filled the first buffer.

2. Stereo and Fibonachi packed samples not yet supported (there are loading
   problems - play them with 'Zound' instead for now).
Fix: Stereo is OK now if you use the above size option (it actually worked
   in RAM: before too - but I didn't enable it for the prerelease). As for 
   Fibonachi: it's not too hard to fix, but I've never seen anyone using it -
   is it worth the effort? If you happen to have a Fib-sample - PLEASE send it
   to me - I don't have the patience to reconstruct one by hand...

3. Could hang forever if someone stole the channel. 
Fix: So, I didn't check everything in 0.99 - now I do (I hope... ;-)

4. -s and -l wasn't used in 0.99, now it is.

Thanks to mjl@alison.at for the idea.


Distribution
============

  UPD is not public domain. A friend of mine advised me to call it
"Freely Distributable Copyrighted" instead. That's close enough.  
If You wish to include it with a commercial program feel free provided 
that You send me a registered copy.

  As always, Fred Fish is free to include it in his library.

  Source code? You mean there is something to IMPROVE??? Right, send
me a message then and I'll think about it...





    Jonas 'Zaphod' Petersson
    Albrektsvagen 113A
    S-603 53  Norrkoping
    SWEDEN
    Phone: +46 11 162517

    zaphod@magrathea.indic.se                   /* At home */
    zap@indic.se			        /* At work  */
    zaphod@slaka.sirius.se               	/* Absolute software */


Feel free to send comments, bug reports (huh?), money, coke, beer, girls...

Just a "Hi, I liked your program" is as good as a few bucks - I wrote this
because I needed it, not to make money out of it...