ACI ~ AIFF decoding ?

Not a direct answer but here's a utility which converts audio you may be able to reason it from 

https://github.com/nippur72/apple1-videocard-lib/tree/main/tools/wavconv

I put source for a converter on my website a number of years ago.

It can be found on the following page.

https://www.willegal.net/appleii/apple1-software.htm

-Mike W

In post #1, 'Mike-K8LH' wrote:

" Is there a specification for the format of program files in Apple 1 AIFF format ?" 

Uncle Bernie answers:

It's the same as for the Apple II. Except that the Apple II recordings add a one byte EOR "checksum" over all the bytes.

Neither in the Apple-1 recordings nor in the Apple II recordings there is any information embedded about begin address, end address, number of blocks, program start address ... nothing. It's just a plain data byte stream after the header tone.

I fixed that with the "extended format page" in the PROMs which came with my Apple-1 kits (now sold out). The extended format recordings have autoload and autostart features for any number of recording blocks. And they stll can be loaded on an Apple-1 or Apple II not having my PROMs.

But for just finding out about how the Apple-1 cassette interface works, any book on the Apple II should do, but check that it covers the topic. The cassette interface fell in disuse after the Disk II system came out in June 1978.

The AIFF as such is a different topic. This is a generic sound file format still in use nowadays. Not sure if that was what you were looking for.

- Uncle Bernie