Saturday 21 September 2013

Melodies - Part 2 : Those significant bits

To read part 1 of this post, click here

*********

A bit is just a ‘0’ or a ‘1’ – it is such a small piece of information in the entire computing universe filled with terabytes and petabytes of data.

It takes 16 such bits to store a value between -32768 to +32767 (65536 unique values!)

If the unique values refer to an audio source, then you get to hear 65536 unique values if you had just 16 bits with you! Let us call this unique value of sound a ‘sample’

Now, it gets interesting – from one second of audio, 44,100 such unique values are taken and 16 bits are given to each of these 44,100 samples resulting in a total of 705600 bits worth of information for just 1 second of audio. Imagine the quality of the sound when 705600 bits are used to say what the audio should sound like in that particular second.

If you have used a stereo headphone/speaker, you already know that there are left and right channels superimposed on one another to create a stereo sound. So, add a further 705600 bits to store the information on the second channel. One second of stereo sound, therefore, requires 1411200 bits! Since we know 8 bits is a byte and 1024 bytes is a kB, we can work out that one second of digital audio needs 172 kB!

A song is approximately 5 minutes or 300 seconds. So, we arrive at 51679.8 kB for every song or moving on to more common megabyte (MB) terminology, a digital audio song needs atleast 50.4 MB.

*********

So, with 50 MB at your disposal, you could have one full song stored on your personal computer as a data file and play it over and over again – excellent sound quality – each time every time. This format was referred to as Compact disc digital audio and eventually led to the birth of this:

       

A compact disc player was specialised computer which took only a CD-DA disc as input, read the zeroes and ones on the disc, and converted it into high quality music. A CD-R was hailed as revolutionary because of the excellent quality of music it produced. Suddenly, all well recorded and digitally re-mastered cassettes sounded pale in comparison to the crystal clear music that these CDs produced. Those with cars even wanted ACD players on it instead of just cassette stereos. People flocked to electronics stores to exchange their ‘two-in-one’s for ‘3-in-one’ or ‘4-in-one’, the third and fourth functionality being audio and video CD playing capabilities. The compact discs, which were till now being used to store computer data now started to be sold in the audio CD format pre-recorded disks like this. However, if you had bought the original audio CD, you could also make a backup of the data on your system. Even personal audio recordings could be stored on a system and recorded to a disc using a process called BURNING a CD-ROM. All you needed to have was CD- R hardware on your system, support software and of course, the blank CD-R to burn, which came initially with 650MB of storage allowing 12-13 songs. Very soon, there was space for about 18-20 songs, sometimes offering space upto 850 or 900 MB. And yes, they were a little costlier than cassettes, with CDs priced at around 100-180 per piece

 
Some of the biggest selling music on Audio CDs - inlay card comes engraved on Kasoor's CD while a glass case cover with traditional inlay card is how RHTDM was sold

Around the same time, there were changes in the Indian retail scene which led to organised retail and malls entering India. And that was when stores like ‘Planet-M’ and ‘Music world’ became popular. People liked to shop at these big outlets because they could listen to the music on the preview players before buying the albums. These outlets were usually located in city centres and it was super convenient to hang around in a airconditioned planet-m listening to music, while waiting for a friend or colleague. Popstars and celebrities liked these stores too – they could visit these places and launch their albums and promote music sales. Fans got an opportunity to meet the stars – the music worlds, and planet-Ms were roaring successes.

Continued in Part 3....click here to read part 3

PS:
Images courtesy: Google images and Wiki images. All images are copyrights of their respective owners, used here purely for illustrative purposes

2 comments:

Madhur said...

Looked like this was going to conclude with how 50 MB/song got compressed to 5 MB/good quality musical experience stored on mobile phones .. scope for the next blog maybe :P

Shashia said...

Madhur,

Bingo! Read part 3 for the concluding piece... It will go live on my birthday :)