Audio codecs are defined as software applications of hardware devices (with the same kind of software) that can compress audio files and then decompress them. In fact, the codecs used for compression and decompression work with opposite principles, but they are quite similar to each other in the manner of their working
The formats used by audio formats are any applicable digital audio formats that are commonly used. For transmission over the Internet, codecs can also compress and convert files into streaming audio formats.
The word 'codec' is derived from coding-decoding, which is what a codec does. It first codes the digital data into a small compressed form and then plays back the data by reconverting it into the original form.
Audio Codecs – How do they work?
Audio codecs work with the principle of audio compression. This is a process of reducing the size of an audio file so that it is covered within as few bits of data as possible. The idea is to remove all unnecessary sound bits and bundle them into a smaller format so that they are compressed. When the file needs to be played back, a decoding system is put into play which can expand the files again so that they can be played.
Lossless and Lossy Audio Codecs
There are two types of compression that audio codecs can perform. Based on that, they are called as lossless and lossy audio codecs.
Lossless audio codecs retain a copy of the original audio files before converting them, so that any kind of qualitative or quantitative loss becomes reversible. However, this also increases the size of the file even after compression. It is difficult to have a lossless audio codec that can compress an audio file below 50 to 60% of its original size.
Lossy audio codecs are those that do not retain any previous information. They compress the audio to the smallest size possible and transmit them where they are decoded to a playable size. However, there is a danger of loss of data because of the fact that there is no backup created. The brighter side of this is that lossy audio compressed files are substantially smaller in size. These can easily compress the files to 5 to 20% of their original size.
Today, most audio codecs available in the market are of the lossy type. Though they will cause a deterioration of the quality of the file, they are good for online transmission and even storing on discs. For that reason, people prefer lossy audio codecs over the lossless ones.
Audio Codecs – The Tradeoff
There is always a compromise involved when audio codecs are used. It is not possible to predict in advance how these files will be compressed and whether they will play at good quality upon being decompressed or not. This is especially because most codecs used today are lossless. Though this becomes ideal for sending digitally compressed audio files over the Internet, they also mar the original quality of the recording. Hence, these audio codecs are used only sparingly and only in areas that really require them.
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