Neil Turner's Blog

Blogging about technology and randomness since 2002

Apple Lossless Encoder

One new iTunes feature that slipped by me was the new ‘Apple Lossless Encoder’. Unlike music formats like MP3, AAC and Ogg Vorbis, lossless encoding results in no loss of quality – the music file sounds exactly like the original. The downside to this is that files compressed using lossless compression are typically quite a bit larger than their lossy counterparts.

With the largest iPod topping 40GB it’s hardly suprising that Apple have adopted this – I’m sure the majority of people will never fill that much (even I have only 6-7GB) so the extra space can be set aside for higher quality files. What is suprising is that Apple chose to adopt their own format, and not one of the (many) other lossless encoding formats.

If you thought there was a format war amongst lossy encoders then you’ll be knocked back by how many lossless ones are out there. There’s at least 14, although not all of them are as good as each other. Thankfully, lossless formats are easier to compare since output quality isn’t a factor, but a good format will have quick encoding, a small output file size, many features, and would preferably be open source too.

The most popular is FLAC (Free Lossless Audio Codec), which is now being steered by the Xiphophorus Foundation who are also steering the Ogg Vorbis format. It’s arguably not the best format out there but it’s good enough and it’s entirely open source. It’s well represented on almost all platforms and is even in some hardware players. Monkey’s Audio is a little faster but isn’t so well supported, being restricted to Windows and a command line encoder in Linux. Although it is open source, development has been a little slow of late, and it lacks some features compared to FLAC. Shorten is another popular format.

Apple Lossless Encoder (or ALE for short – nice acronym), is, sadly, based on none of these. It’s a new format which is closed source and currently only works in iTunes (Mac and Windows) and through QuickTime, although a dBpowerAMP codec is apparently in the works. It is quite well featured, offering streaming and seeking support (which a suprising number of other formats lack), and is obviously supported on the iPod with the addition of the latest firmware update, so on paper it has a similar number of features to FLAC. It is, however, slower at encoding and decoding, and files are typically a megabyte or so larger, according to this comparison provided by the FLAC project, however this HydrogenAudio topic suggests it is faster. I’m guessing Apple may have optimised it for the PowerPC processor, in which case compile times on Mac OS X would be better than in Windows.

It’s just a pity that Apple took the decision to re-invent the wheel when good alternatives already exist, although this Macworld column reckons this is because Apple may want to add DRM to it in future so that punters can buy higher quality files from the iTunes Music Store. AAC was an open(-ish) format and look how quickly that was cracked. On the other hand, I doubt the record labels would be interested in giving away their songs on the internet at full quality, based on their previous boneheaded decisions.

There may also be reasons, such as patents or problems with embedding FLAC in the iPod firmware, but seeing as other hardware manufacturers have managed it this seems strange.

In any case, it’s an interesting development. Any support for lossless audio in iTunes is a good thing, I just wish that Apple had gone with the herd rather than go on a tangent and then confuse people. What I would like to know is whether the WMA import function of iTunes allows you to convert them to ALE, since then you wouldn’t lose any quality – I couldn’t find anything that suggested this in my research for this article.

6 Comments

  1. My question is how many songs can you get on a 40G iPod? I have 21G already with about 4200 songs at 192k. If convert them to ALE (or redownload my disc collection) will I max out the 4200 on the iPod or will I have room for more songs?

  2. If you converted all of your music over, then with that many songs you may well max it out. Personally I’d suggest converting the songs you really like, and then seeing how much space there is. While losslessly compressed audio sounds better than lossy audio, it will take up much more space.

  3. I think you’re mistaken here. Apple aquired some time ago the company Emagic (the guys of Logic). Back in the nineties Emagic developed a codec by the name ‘Emagic Zero Loss Audio Packer (ZAP)’. This ZAP-compressor/decompressor is able, just as is the case with ALE, to ‘zip’ music without losing quality.
    This format was available for Windows and Macintosh users.
    Now, with the Acquisition of Emagic Apple dropped support for the Windows-platform, yet, a lot of technologies are used in their pure or somehow modified form in applications like Quicktime, GarageBand, Logic and … iTunes.
    Ofcourse the format has evolved, but somehow I do not believe it’s a totaly new format. I think ALE is a direct succesor of ZAP.

    Lukas Pruski – Amsterdam / the Netherlands

  4. I’ve ripped a couple of CDs to ALE and noticed that each track ends up with its own kbps rate. They tend to be in the 800-950 kbps range. What I don’t like is that no other non-Apple apps support the format (e.g. Toast). I’m holding off for now — AIF or MP3 for now, depending on application.

  5. I think the reason Apple didn’t use an existing lossless codec is because FLAC and SHN are relatively processor intensive to decode. The iPods don’t have a very beefy processor, so they are probably physically incapable of playing the existing formats. Apple heard the demand for a lossless codec in the iPod, but couldn’t find an existing one that would work. They created ALE to meet the demand while also being backward compatible to even the first gen 5GB iPods. Maybe the next gen of iPod will have a beefier processor and support for and open-source lossless codec.

  6. FLAC is intentionally asymmetric – encoding is processor intensive, decoding is very easy. Witness the Rio Karma. http://flac.sourceforge.net
    ALE taxes my processor about 50% more than FLAC while decoding, though both are seemingly pretty easy. iPod could easily be configured to play FLAC, but Apple’s in the unfortunate position of begging for iTunes content from record labels, and seems to be bending over backward to implement even more restrictive digital rights management with each version of iTunes.