Digital Data — Audio

Data Formats:

Everything is 0s and 1s for a digital computer and thats how data is stored, retrieved and manipulated. There are more than 1000 types of data we store and use in computers starting from a simple text, video, audio, graphics, games, etc…

If computers can only recognise 0 and 1, how different things are handled. Thats where the formats come in picture. Different alignment of binary data gives different types of file formats and they represent different file types.

Data Encoding:

How efficiently you store these 0s and 1s of different formats varies for different methods and optimised for different usages. Every data we talk here are complex and have lot of dimensions. Capturing all of them efficiently is done by different systems called Encoders. In this post, lets us discuss about various parameters of audio digital data.

Audio Data Parameters:

Audio Sampling Rate:

We all know that audio is a continuous analogue data and to have a digital equivalent we need to build the discrete equivalent fair enough to reconstruct the original data. This can be done by sample the intensities of the signal at different time. More formally we say we need capture analogue audio data at some frequency a.k.a Audio Sampling Rate.

Definition: It is the number of samples of a sound that are taken per second to represent it digitally. More the samples are taken per second — accuracy will be more.

The following tables gives an idea:

Channel:

An audio channel or audio track is 1 audio signal stored representing the whole or part of audio. Based on the no.of audio channels stored in audio file — we reproduce the original sound @ receiving end. The following list gives an idea.

Bit rate:

It is the no.of bits transferred/processed per unit time (per second). In current context — It is the no.of bits required to represent 1 second of media data. Both MP3 and AAC audio format use lossy data compression.

Typically the audio quality improves with increasing bit rate:

References

• https://en.wikipedia.org/wiki/44,100_Hz
• https://en.wikipedia.org/wiki/Bit_rate
• https://trac.ffmpeg.org/wiki/AudioChannelManipulation
• https://www.cs.cf.ac.uk/Dave/Multimedia/node150.html

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