20.07.2012 | 15:16
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MP3
MP3s, you have them. We're pretty sure you're aware of what these are. A compressed, or "lossy" format developed by the Moving Picture Experts Group. Clever algorithms maintain fidelity, while reducing file sizes, by compressing the data which is believed to be hard to hear in its original form. When encoded at a bit rate of 128Kbps, the resulting file will be approximately 1/11th the size of the uncompressed original. This ratio obviously changes when a different rate is employed. For example the maximum bit rate of an MP3 is 320Kbps which is a much more favorable compression ratio nearer to 4:1. Should you wish to know more about the origins of the ubiquitous specification, there are lots more details about the MPEG-1 and MPEG-2 layer III standards online, which make excellent restroom reading, but are beyond the scope of this article. The positives of the MP3 format are well-known -- small file sizes with minimal impact to audible quality. As such, it has been adopted as the standard format for many media players and devices. The downsides are that, no matter how good the final result is, you are losing some data on the way, which for purists and audiophiles isn't ideal. Many arguments have been had about the noticeable differences between a high-bit-rate MP3 and a WAV file which, to date, have never been truly settled, and likely never will.
Myths, lies and damn acoustics
Knowing what makes up an audio file is only part of the story, there are actually a swathe of other contributing factors that can have a bearing on the sound. First of all, your ears. Sadly these aren't digital, and can decrease in reliability over time. Secondly, there's the audio itself. Digital will only reproduce what you feed into it in the first place. If the recording is bad, poorly mixed, or taken from an inferior source, it will only be as good as the weakest link in the chain. So, theoretically, a 128Kbps MP3 file could be better quality than a WAV file, if some of the above factors affect one, and not the other. Another way of thinking of it is that you might convert an MP3 to a WAV, but it won't gain anything in the process (other than extra file size). That said, it's an interesting test to use on that friend who swears they can tell the difference. Only when two files are from the same source are these issues relevant. It may seem obvious, but the temptation can be to fixate on the pure numbers and not some of the equally vital external factors.
Go on to any audio forum, and it won't take long before you find a thread about which format is the best, or whether you can hear the compression in MP3s and so on. In fact, don't ever do that, unless you want to read pages and pages of heated debate between parties solidly determined of the others' incorrectness. Each format has its merits, and the most important factor (particularly where music is concerned) is that it sounds good to you, and that you enjoy it. However, knowing that low bit depth or sample rates can affect your end result, will arm you with the tools to get the most out of your audio next time you're encoding it.
www.engadget.com/2012/07/19/engadget-pri...igital-audio-basics/