From mailserv@gaia.ucs.orst.edu Sat Apr 23 18:17:41 1994
Precedence: Bulk
Date: Sat Apr 23 14:46:27 PDT 1994
From: gus-sdk-request@gaia.ucs.orst.edu (GUS Programmer's Server)
Reply-To: gus-sdk@gaia.ucs.orst.edu (GUS Programmer's Digest)
Subject: GUS Programmer's Digest V10 #15

GUS Programmer's Digest     Sat, 23 Apr 94 14:46 PST     Volume 10: Issue  15 

Today's Topics:
                        GUS Programmer's Dige
                   GUS Programmer's Digest V10 #14

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	- Meta-info about the GUS can be found at the end of the Digest.
	- Before you ask a question, please READ THE FAQ.

----------------------------------------------------------------------

Date: Thu, 21 Apr 94 06:34:34 EST
From: jmorris@ace.com (Cuthalion)
Subject: Re: GUS Programmer's Dige

{gus-sdk@gaia.ucs.orst.edu}
 @1> Subject: Audio Compression

 @1> Hiyah everybody, I've asked this before but does anyone out there
 @1> know of any algorithms/code for off-line (but in-program) compression
 @1> of audio samples. I want to write a routine that will sit between the
 @1> file system and an XMS-memory system. Help would be greatly appreciated
 @1> as the code is intended for use on my final-year degree project which
 @1> is due in about 2 weeks!

        A simple huffman coding of the delta values should work reasonably
well.  You should be able to find information on huffman coding in some
book, if you're not familliar with it.

 .. DOS never says "EXCELLENT command or filename"...
___ Blue Wave/QWK v2.12

------------------------------

Date: Fri, 22 Apr 1994 10:51:08 -0400
From: davidm@marcam.com (David MacMahon)
Subject: Re: GUS Programmer's Digest V10 #14

>Date: Thu, 21 Apr 1994 15:06:42 +0100 (BST)
>From: a3_clark@csd.uwe-bristol.ac.uk (A Clark)
>Subject: no subject (file transmission)
>
>As I'm recording, first to XMS
>memory, I won't need an 'on-the-fly' compression routine, but merely a 
>routine that can compress the samples on it's way between the XMS memory
>routine and the file-handling routine.

As I said before, set up your stuff to record to files.  That way you can 
record to a RAM drive if you really want to use XMS instead of hard drive 
space, but at least you will have the option.  Then you can use Stacker to 
compress the files as you copy them from the RAM drive to the hard drive.  
Can you Stack a RAM drive?  If so, you would then have the on-the-fly 
compression stuff that you want.  (Assuming that the I/O speed of a stacked 
RAM drive is fast enough.)

>It appears to lock-up the machine
>while a routine serving the timer1 interrupt displays the elapsed time.

It sounds like you are using DOS routines for displaying the time.  DOS is 
non-reentrant.  That means that while you are in an interrupt service 
routine (ISR) you can't use DOS routines.  Alot of C library functions use 
DOS routines. Things like printf and fwrite definitely do so you can't use 
those functions in an ISR.

As far as not being able turn on the mic input, look closely at these 
excerpts of your code and tell me if you notice any thing wrong.  (Hints: ^^^^)

>if(UltraGetLineIn()==TRUE)
>                     ^^^^
>    UltraDisableLineIn();
>else
>    UltraEnableLineIn();
>
>if(UltraGetMicIn()==FALSE)
>                    ^^^^^
>    UltraDisableMicIn();
>else
>    UltraEnableMicIn();
>
>if(UltraGetOutput()==TRUE)
>                     ^^^^
>    UltraDisableOutput();
>else
>    UltraEnableOutput();

Dave

------------------------------

End of GUS Programmer's Digest V10 #15
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