How do you calculate bitrate for a non compressed audio file

Question

For an uncompressed file I thought it was

SampleRate / (NoOfBits * NoOfChannels) = BitRate

which would give

44100 Hz / (16 bits * 2) = **1378 kbps **

However this bitrate calculator returns 1411.20 and when I look at the properties of an actual AIFF file in iTunes it also returns 1411 kbps.

So I assume my thinking is incorrect, what have I missed

Answer 1

Your formula is incorrect - it's just a coincidence that you're getting something close to the right answer (albeit with a handy change of units!).

For uncompressed audio it would be:

bit rate = sample rate * channels * bits per sample

which for CD audio would be:

= 44100 * 2 * 16
= 1411200 bits/s
= 1411.2 kbits/s

See this relevant question for further details.

Answer 2

@Paul R is correct, you can see this in the Javascript for the page:

function calc(data){
    var cA2B=data.pA2B; // sample rate
    var cA3B=data.pA3B; // word length
    var cA4B=data.pA4B; // channels
    var cA5D=data.pA5D; // bitrate kbps compressed
    var cA8B=data.pA8B; // MB per hour uncompressd
    var cA8D=data.pA8D; // MB per hour compressed
    var cA9B=data.pA9B; // # files uncompressed
    var cA9D=data.pA9D; // # files uncompressed
    var cA5B=(((((((cA3B)*(cA2B)))*(cA4B)))/(1000)));
    var cA6D=(((((((((cA5D)/(8)))*(60)))*(60)))/(1024)));
    var cA10B=(((((((((cA8B)*(cA9B)))*(60)))*(((cA5B)/(8)))))/(1024)));
    var cA10D=(((((((((cA8D)*(cA9D)))*(60)))*(((cA5D)/(8)))))/(1024)));
    var cA6B=(((((((((cA5B)/(8)))*(60)))*(60)))/(1024)));
    data.pA5B=cA5B; // the bitrate for uncompressed
    data.pA6B=cA6B;
    data.pA6D=cA6D;
    data.pA10B=cA10B;
    data.pA10D=cA10D;
};

I added the comments and the (slightly more) pretty printing.