What is Codecs – A Powerful Technology You Should Know Today

This column will provide you with sufficient knowledge to comprehend what is codecs. If you are a frequent visitor of this blog then you will realize why this post focusses more on audio codecs.

But I will also try to cover what we all call as a codec in general. Moreover, understanding this topic is of great importance as the data which we process today are made available on one or the other codec format.

So, let’s get started with this article and I hope you like.

Codecs – In General

The title ‘Codec’ is about encoding and decoding of data. Moreover, ‘codec’ is a short form for “Coder-Decoder”. A codec is an algorithm which is used to encode data. Furthermore, this data can be in any form such as audio or video. Therefore, whenever a data is processed in any device the data is decoded before using running the program.

The following video is a great source of information as it tells in detail about compression. Also, it is important to know that codecs are not meant for data compression but today almost all the codecs provide data compression, thereby reducing the size of the original file.

Therefore, today codecs are the factor that enables data compression.



Data compression can be in many forms, eg files, audio files, video files etc. So, I will discuss on the audio and video compression. Both the above sections can be further divided into Lossless and Lossy Compression.

You can save the image for future reference.




Audio Compression

I have a great source for both this and the other topic. I recommend you to check these videos out as they provide great information on the topic.


Video Compression

Now, there are two main ways of compression and the time has come to learn the two ways in detail.

Lossless Compression

As the name suggests, there is no loss in the compressed data. Usually, whenever anything is to be compressed we have to compromise with the loss in the file quality this happens because during the process of compression some data bits are lost.

But Lossless form of compression uses a specialized class of algorithm which allows the original data to be perfectly reconstructed from the compressed data. This is an improvement over the other type which we will soon discuss.

Some examples of this type of compression are –

  • ZIP file
  • GNU ZIP [ gzip ]
  • PNG Image
  • GIF

When Is Lossless Compression Used?

It’s quite logical to understand the usage of the lossless compression technique. You won’t desire to lose any of your files details if the file matters to you a lot. Therefore, this method is used when the loss of data during compression is unfavorable.

How Do Codecs Work?

Almost all the lossless compression algorithm does two things in sequence.

Generation of Statistical Model

  • Generation of a statistical model is the first step of the sequence. Here an above-mentioned model is prepared for the input data.


  • The second step uses this model to map the input data to bit sequences in such a way that the bit with most probability [frequency of appearance in the file] will produce shorter output than the less probable data bits.

The primary encoding algorithms to produce these sequences of bits are Huffman Coding and Arithmetic Coding. Out of these two, the Arithmetic coding achieves compression rates close to the best possible for a particular statistical model.

Lossy Compression

If you are well known with Information Technology, lossy compression also called as an irreversible compression is a class of data encoding method which uses vague approximations and partial data discarding to interpret the content.

This method of compression allows great compression of data but at the same time, the quality of the compressed data is less. The degradation of the image is sometimes so much that the end user is also able to notice the drop in the quality.

One of the most used and famous types of compression that uses this technique is called the JPEG. Furthermore, this is used for compression of images.

Some other examples of such compression are –

  • MPEG
  • MP3

Such type of data is never used for professional or other important documents.

Audio Codecs

An audio codec is a device or program which is capable of encoding and decoding audio. Audio codecs have the objective to represent the high-fidelity audio signal with a minimum number of bits while retaining the quality. Such an audio codec can effectively reduce the storage space and the bandwidth required for transmission of the audio file.

Moreover, audio codecs are also available in hardware form, such codecs contain both an analog-to-digital (ADC) and digital-to-analog (DAC) converter which run on the same clock signal.

Some of the Audio Codec Formats are as follows –

  • FLAC – Free Lossless Audio Codec
  • WAV – Waveform Audio Format
  • MP3 – Moving Picture Experts Group Layer-3 Audio
  • MORE
  • WMA – Windows Media Audio
  • ALAC – Apple Lossless Audio Codes
  • Ogg Vorbis
  • AAC – Advanced Audio Coding
  • AIFF – Audio Interchange File Format
  • DSD – Direct Stream Digital

aptX Compression Format

This is a very important feature that we use today in many wireless gadgets. If you don’t know, this is the technology that enables the transfer of high-quality sound through Bluetooth.

This is used in consumer and automotive wireless audio applications over Bluetooth A2DP. The music which we listen to on wireless headphones is due to this feature called aptX. This codec was introduced by Qualcomm which enables CD-like quality wireless audio. Because this method solves the problem of sending the full music bandwidth over Bluetooth.

A Bluetooth connection is more like a pipeline of data developed between devices. As this pipeline has a maximum width, there are chances when difficulty may arise while sending large audio files through it.

Here aptX comes into the picture. AptX provides a solution to this problem by compressing the size of these audio files so that it can be transferred easily through the wireless pipeline.

Most importantly, this process doesn’t affect the sound quality. Moreover, this technology is even backward compatible. Therefore, the music keeps transferring even when aptX is unavailable.


Finally, this wonderful bit of awareness has appeared to an end. I assume you appreciated this throughout.

Furthermore, share this with your friends who are curious about knowing such tech-insight stuff.

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