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Lossless Compression

Of course given that flash memory is so cheap now and that good 2GB players can be had for under £50, you could be forgiven for wondering what the point is in encoding at anything lower than 192kbps or its equivalent. After all, if you were to rip a 70 minute CD at 192kbps CBR, you'd still be able to fit 21 albums onto a 2GB player. Move up to a hard disk-based player and the number shoots up - 319 albums on a 30GB player, 852 albums on an 80GB player.

If, however, after playing around with a few ABX tests you've convinced yourself that you can tell the difference between 320kbps encoded MP3 or Ogg Vorbis q10 and the original WAV - unlikely, but possible - the only alternative is to encode your music in a lossless audio compression format.


Flac has widespread hardware support among media streamers, including the excellent Logitech Squeezebox 3.


These compression techniques don't use the perceptual model that lossy codecs do because there's no loss of information. Instead, the goal is to produce bit-for-bit perfect copies of the original CD Audio files, but squeezed into a much smaller space.

Lossless audio formats are ideal for archiving and backing backups of your CD collection on your PC as you can fit far more into a given space and yet still enjoy 'perfect' audio. On a more practical note, if you listen to your music in different formats, it makes sense to keep it losslessly encoded in a central location to make transcoding to a lower quality lossy format simple as and when you need it.

There are various technologies around, but the differences are much less marked than with lossy encoders. Quality is a non-issue, since all lossless codecs are designed to replicate the original audio data with no loss of information, a bit like compressing a documents using Zip.

Instead, the differences tend to focus on more pragmatic issues, such as the speed of encoding, which can affect battery life on portable players, whether or not a license fee is payable for developing with a certain codec and how easily a given file type is adaptable to different situations, such as streaming.

Both Apple and Microsoft offer lossless encoding via iTunes and Windows Media Player, and there's a whole raft of other competing technologies such as Wavpack, Monkey's Audio, Optimfrog Shorten and Tak.


iTunes offers lossless AAC encoding, but you'll have to manually select it.


The format enjoying widest support at the current time, however, is Flac (stands for free lossless audio codec), an open source codec developed by the people behind Ogg Vorbis. And, if you're encoding losslessly, wide support in hardware is probably the one, big differentiating factor.

Many high end 'audiophile' digital media players now support Flac, for example, as does my current favourite portable player, the Trekstor Vibez, and a number of wireless audio streamers, such as Sonos' wireless music system and the wonderful Squeezebox 3. The latter devices allow you to stream CD quality audio across your home network.

Flac is the ideal format for a high quality, connected audiophile hi-fi system and performs a compression that typically results in files between 50 and 70 per cent of the original file size.

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