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Aug 29: This is the first live use of the new web template from Andreas Viklund. I still have some tidying up to do but I was very pleased at how easy these templates are to use.

Aug 28: Canon have released the latest EOS 400D digital SLR. I wish I had waited a bit before buying the EOS 300D!!

Links:

• FLAC
• Ogg Vorbis

Audio Formats

This section is an attempt to categorise and explain some of the various file formats in use for storing digital audio.

This little section was inspired by looking at the quality of music downloads and trying to determine whether or not they met certain standards for what used to be called Hi-fi. I am led to the conclusion that when it comes to music downloads we are not far removed from the quality found on the old audio cassette tapes. After all, downloads are aimed at the same mass market, where the accent is obviously on popular music and where the player is most likely to be an iPod. Much of the reason for this fairly low quality is the low bitrate, typically 128 kb/sec. If you are looking at storing your music on a computer then it is probably well worth your while having a look at some of the alternative file formats. Then you need to look around and see how you can find music that meets your quality requirements.

Lossless Compression Formats

Lossless formats allow you to store the audio in digital format without losing any of the sound.

WAV

WAV (short for WAVeform audio format) is used by Microsoft and IBM as the standard for storing audio on PC's. It is a variant of the RIFF bitstream format and is simuilar to that used on Apple computers. Since most applications recognise this format it is very useful for holding the audio data in a raw digital format prior to some further processing. For example GrooveMechanic reads WAV files, removes the clicks, rumble and hiss and then can export them to MP3 and OGG. Audacity uses something called an AUP file but can still read and write WAV files. WAV files are quite large, so they are a little unsuitable for storing music for players and sending over the internet.

FLAC

FLAC stands for Free Lossless Audio Codec. Grossly oversimplified, FLAC is similar to MP3, but lossless, meaning that audio is compressed in FLAC without any loss in quality. This is similar to how Zip works, except with FLAC you will get much better compression because it is designed specifically for audio. The main drawback is that there are not many devices (other than your PC) that support this format - see the FLAC homepage. On the plus side it seems to be gaining ground in the PC world with Winamp and Audacity now having plugins supporting this format.

Lossy Compression Formats

The most common file formats for compressing music and spoken word are MP3 and WMA. There is also a further format called OGG which is gradually gaining acceptance.

WMA

Windows Media Audio (WMA) is the format that Microsoft would like everyone to adopt instead of MP3. The one advantage that WMA does enjoy is that it produces smaller files; however with increasingly large storage available even on IPODs, this is not such a big deal these days. Try some samples of music by going to the Ogg Vorbis and listen to see just how much music is being lost for this extra compression.

MP3

Officially this is called MPEG Audio Layer 3 where MPEG stands for Moving Picture Experts Group; much easier to call it MP3. This group is responsible for creating international standards for compression, decompression and processing of audio and moving pictures. MP3 when recorded at a reasonable bitrate (i.e. > 160kbps) is meant to be very close to CD quality. The compression ratio achieved is about 10 to 14 times the original, so instead of a track taking 30 MB of storage it only requires about 3 MB. It has rapidly become the de-facto standard for digital audio, although there are many attempts by Microsoft and others to supercede it. Some competition is healthy after all.

AAC

AAC (Advanced Audio Coding) was designed as an improved performance codec relative to MP3. It now has quite a large following and could be used as the new standard for DAB because it is purported to give the same sound quality at lower bitrates than the current DAB MP2 standard, meaning more or higher quality radio stations can be squeezed in. There are already a number of net radio stations using AAC, mostly at 48 kb/sec or less. Note that Apple iTunes downloads are all formatted to AAC standard.

OGG

Quoting from the Vorbis site; "Ogg Vorbis is a new audio compression format. It is roughly comparable to other formats used to store and play digital music, such as MP3, VQF, AAC, and other digital audio formats. It is different from these other formats because it is completely free, open, and unpatented." Reasons quoted for using this format range from "it sounding better than MP3 for the same file size, to it is patent free so there are no licence fees to pay. If you are interested in recording speech then you should note that Vorbis primarily recommend this format for music only. I have tried this format and agree it sounds very similar to MP3, but I would be hard pressed to detect a clear superiority - try it and see for yourself.