Digital audio formats and storage




In the last chapter we understood the structure of digital audio . In this chapter we will have a quick look on the different types of storage formats on the computer.

The waveforms that we discussed are stored in the computer in binary form. These bits contain the information about the structure of the sound and amplitude.

The audio formats falls under three categories:

1. Uncompressed audio formats

The highest quality!

These are Digital Audio files that do not lose any audio information about the waveforms and frequency.

.WAV - on windows and .Aiff on macintosh computers are good example of uncompressed audio formats. These files don't lose any data and have the highest quality possible.

Audio Cd data .cda, is another good example of uncompressed audio format.

You would need to always create uncompressed audio format when you make songs on the computer. These formats are useful when the audio is used in concerts in big halls or stadiums at marriages and DJ party. Using compressed files in these places will not give the same warmth and punch in the beats that an uncompressed full info audio file would have.

2. Lossless compression formats

Keeps the quality and remove the unncessary parts to reduce the size to half.

Lossless compression is a technique where in audio is stored in such a way that the unnecessary part (silence) is left to reduce the file size. It usually gives acceptable results and is a good alternative to uncompressed audio.

Suppose there is an audio clip which contains some seconds of silence between the chorus and the bridge, the lossless compression technique would skip those parts and hence save some disk space.

Lossless compression formats (such as the most widespread FLAC, WavPack, Monkey's Audio, ALAC/Apple Lossless) provide a compression ratio of about 2:1

So if if an uncompressed audio is of about 100 Mb the lossless compressed version of the same file would be around 50 Mb given almost exactly same results.


3. Lossy compression formats

This format makes approximation in data and loses on quality.

The third type of audio format is one in which certain approximations are taken. These approximations upto a certain level are not noticeable by human ear.

However, if you play compressed files in large environments you might be able to make out the difference in the sound quality.

Examples: Mp3, Ogg, wma and others


Conclusion
It is important to understand some basic about how audio is compressed or used in the computer. This will help us in managing aur audio later on.

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