I've been poking around those innocuous-looking .aif files in the GarageBand loops folder, and I've realized something... these are FAR more than simple ACID-type files or REX2 (or pHATfiles) which simply store transient, tempo and key information.

It appears the Apple Loop file format can store the following

1. A rendered version of the loop (what's in the standard aiff file, and and the reason you can load it into any application that supports aif)

2. Transient, key, and tempo information. (like ACID, Rex2 and pHATfiles)

3. The midi information used to create the loop.

4. The EXS patch used to create the loop (including samples, it appears, but I'm not sure) (!)

5. A 'channel preset' with effects settings for processing the loop.

What's the practical application of this?

1. In GarageBand, if you drag one of these loops to an audio track, you get an audio-style waveform reminiscent of Logic's arrange with the added benefit of ACID-style time-stretching and pitch-scaling.

1. If you drag one of these loops to a MIDI track, you get the MIDI data used to create the loop (note that that midi track could be triggering a completely different instrument, allowing you to mix and match performance data with different sounds freely.) You could also quantize, change individual notes, etc.

2. If you drag one of these loops to an empty area in the arrange (i.e. where there is no track already) it will create a new track with the channel settings, sampler patch (aka 'software instrument' in GB) and midi data TO EXACTLY REPRODUCE THE LOOP. But with more flexibility than loop based soundware has EVER provided.

This is important: instead of 'slicing' up a rendered audio loop, these apple loops can be thought of as 'open source' loops -- you literally have the program material (sampler patch, performance data, and effect settings) the sound designer had when he created them! Also, because these are midi-based, they need not be drums, be ANY type of program material. (For example, the loop I used to try all this out was a pop ballad piano loop complete with chords and piano).

Forget ACID-style time stretching, this is the ultimate in flexibility for all types of loops. Imagine getting a drum loop and deciding it's too compressed. Simply turn it off. Or change the hat sound (or entire kits). Add to this the meta-tagging features of Apple Loops (the search engine is great, as anyone who has used Soundtrack can attest to).

While this puts an (unfruitful) end to a year plus of research and development for me (the death of MetaGroove™, I'm afraid), it's EXTRAORDINARILY exciting for me as a musician to see a platform vendor do something so right and so smart. While many of us scratched our head at the apparent anti-climax of Logic Pro 6, Apple slid a revolutionary new technology into their introductory audio application right under our very noses.

Mark my words. Apple Loops are big news.

Hats off to my colleagues at Apple. Brilliant.

Art

aahhh - time to buy an emac, fxteleport and a biiiiiiiiiiiiiiiiiiiiiiiiigg amd supercomputer to handle all the hits i'll make.

fortune, fame and blondes - here I come!

The thing is though, most of the metadata (sampler patch, effects) is only useful in GarageBand. Aside from that, it's either a plain midi loops, or a sliced audio loop with added key (pitch) information.

Forever,




Kim.

True, until it becomes accepted as a standard. See REX for details.

I don't think so. the sampler patch and effects configuration is only useful if your host (eg GarageBand) has exactly the same effects and sampler patches as GarageBand, or the developers of the loop.

I have a certain feeling that SonyPicturesFoundry Acid5 will be something totally beyond comprehension.

There's an SDK for AppleLoops here