[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Apple II Sound
On 10 Mar 1997 22:33:25 -0800, dastar@crl.com (Sam Ismail) wrote:
>Edhel Iaur, Esq. (LOSETHECAPITALWORDSedhel@bigfoot.com) wrote:
>
>: Well, not necessarily...If you use the 1-bit-audio program that I got
>: & modified from Gary Little's _Inside the Apple //e_, you can get 20+
>: secs on a 48K Apple //.
>
>Pfeh! That's nothing. I was able to record a full 5 minutes into my
>1 meg Ramfactor on my //e! I succesfully recorded Led Zeppelin's
>_The Song Remains The Same_ in its entirety into my apple, with decent
>quality. This was achieved by packing 8 state changes into a byte (each
>bit...) I think I was able to do about 30 seconds in the lower 48K of
>an apple machine (starting at $0800 and going all the way up to $9600).
>
>What was Gary Little's algorithm like?
If I remember right, It was just something that grabbed the Cassette
In's status (1 bit) 8 times, and ROLled it into a single byte, which
got shoved somewhere after $1000 and before DOS. Then, the process
was repeated. I usually had the sampling rate cranked all the way up,
since 1-bit sound can be pretty sickly. I modified his code to get
2.5x his fastest sampling rate, but the quality didn't go up much
(maybe because I killed some of the timing loops ;D ).
It was pretty fascinating writing a friendly shell for his machine
language recording & playing routines: I had a very small amount of
memory to play in, and all variables got smashed when I recorded :D I
suppose If I needed it, I coulda POKEd my variables into zero-page...
I also attempted to let his routines use Aux. memory, but I have no
idea on how to let it use RAMFactor-type memory (I don't have any
anyway, so this bothers me not :) )
--
| / / />___________________ +==Apple // Forever==+
|___ _____ M#M#M#||___________________---__ +-37th Wisest Wizard-+
| \ \ / #M#M#M||___________________--- +- Edhel Iaur, Esq. -+
| / / \_/ \>
http://www.grin.net/~cturley/USA2WUG/FOUNDING.MEMBERS/HOME.PAGES/EDHEL
***For my correct email address, delete all the capital letters***