When people talk about MP3 files and the like, you often hear the term Bit Rate also mentioned, so what’s it all about?
Until the mid 1980s, commercially purchased music was always in analogue format, be it typically vinyl or cassette. In late 1982, the arrival of the now ubiquitous compact disc (CD), co-developed by Sony and Philips, changed all that and revolutionised how we listen to music.
Digitisation
In order to create digital recordings such as CDs, the conventional analogue audio first has to be digitised. The process of digitisation takes the original audio source and chops it up into lots of thin slices. Each slice represents the volume of the audio source for a particular point in time. A digital number then stores the volume level of this slice on the CD. Each slice, or sample as it’s actually called, represents the level of the audio for a mere 23?s (23 millionths of a second).
To reconstitute the audio track, all of these samples are stuck together and the volume level of each sample is sent out to your speakers every 23?s (in the case of CDs). It’s a bit like slicing a loaf of bread and then squeezing all of the slices of bread together again to make it look like the original loaf. Not perfect, but if you squint, you’d never know that difference. CDs are very similar, because the slices are so thin, you don’t know the difference.
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