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Common Audio Formats

audio-formats13There are three different types of audio formats: Uncompressed, lossy compression and lossless compression. The first one, Uncompressed formats are the famously known Pulse Code Modulation Formats. This format does not use any form of compression, hence, the name. This in turn means that we get the complete audio file, completely unchanged, on the expense of a large storage size.

A good example of the uncompressed audio file will be .WAV audio files. The lossless compression which is a compressed audio file, which is essentially same as the original file, but a bit compressed. The quality is not changed nor is there any loss of information in the signal. WMA files are a good example of this type of format. Next comes, the Lossy compression. This type of audio format is used to reduce the files size to save the storage; however, a compromise is done on the quality. Despite, the disadvantage, the lossy compression type is the most famous audio format, which is because the basic information is never lost in this type of compression. MP3 audio file are a good example of this format.

A further breakdown of the audio formats is possible depending on the scale of compression and quality of the audio files, once the compression is performed. Some of the renowned formats are discussed here:

MP3 and Real Player Formats

MP3 is a name given to the file type MPEG with audio layer 3. There are three basic coding schemes used for compressing the audio files: Layer 1, 2 and 3. The MP3 file format uses a layer 3, where irrelevant parts of the audio signal, are removed without affecting the intelligibility of the signal. The irrelevant piece of signal, which could not be heard by human ear, thus making it useless, is removed using perpetual audio coding in conjunction with psychoacoustic compression methods.

A filter bank is applied using the Modified Discrete Transform Algorithm, which improves the resolution of frequency of up to 18 times than that of audio layer 2. The layer reduces the audio file’s data to up to 12 times than the original one. Real Player files are also lossy compression files that are used for streaming purpose and are very popular because of their small sizes and good quality.

WMA, WAV and MIDI formats

As mentioned above, this is a lossless compressed format file. It is similar to the MP3 format, but being lossless means that it could support a higher rate of compression. The Wma file could be of variable size, both small and large, as there is less limitation to its compressions. On the other hand, WAV is the uncompressed format file that was a joint venture of Microsoft and IBM. This is a very common file type that users will find in the default sounds of MS Windows operating system.

MIDI or Musical Instrument Digital Interference is also one of the formats that are found in abundance in MS Windows. It is the standard format used in music industry for devices such as synthesizers. There are various characteristics of sound that are attached with MIDI which includes volume, pitch, delay time, etc.