Re: digital recording mystery

["Tom Ritchford" <tom@swirly.com>]

> I haven't thought it completely through, but I don't think lossy
compression
> works that way.  

I don't think that he means that the compression is
removing time as part of the compression directly --
it's an artefact of the compression process, rather.

ATRAC and MP3 both work by dividing the source up
into a large number of small chunks and picking 
the best encoding strategy per chunk (which is why 
it's "adaptive".)

So unless the chunk size exactly divides the track
size, there's going to be a chunk that's too small
at the end.

If I were writing the encoding, I'd throw away that
last little chunk if it were "completely empty", 
otherwise I'd pad it with emptiness.  So the length
would change just a little bit...

This is just my guess, but that's how I'd go about it.


-- 

I am the wombat.