Mp3 Calculus Chart

Small Chart

So what is this ?

This chart shows how much your audio is squashed when you compress it using an MP3 encoder at the apropriate bitrates shown. It also displays the actual amount of audio you can squeeze on to a normal CD-ROM(650MB capacity).

Generated with a Perl script and a database, both written by Airon / Phase^D.

Download

mp3_chart_1.1.zip(35kB)

containing both charts and sources, including the flat text database, the Staroffice and an Excel version, which both use formulas for calculate everything from the bitrates.

Why was this written ?
To set the tech facts straight. Especialy journalists keep on getting it wrong completly, so here's a chart where the facts are.

There is a bigger chart showing almost all used bitrates, MONO and STEREO, from 8 kbps - mono to 256 kbps - stereo. Go here to check it out.

Here is the basic data from which everything else is calculated :

• Stereo PCM 16bit audio:
  • 1411200 bits/sec = 2 channels * 16 bit * 44100 samples/sec
    This is used to calculate all the compression factors
• Audio CD capacity (usualy raw stereo 44100Hz 16 bit PCM) :
  • 746.9 MB
• CD-ROM capacity for data :
  • 650 MB Since CD-ROM data is far more critical on errors (especially archives) the error correction takes up more space on CD-ROMs and less is available for data.