can anyone explain...

Posted by: intothevoid on 27 December 2012

I was thinking about internet radio streams and how they are always quoted in kbps, whereas cd and hi-res is always referred to by bit depth and sample rate.

A cd is as 16/44.1 which should equate to 705.6kbps but, according to HDTracks, a cd is 1411.2kbps so my calculation is out by a factor of two.

The same holds true for a hi-res 24/192 recording which should be 4608kbps but HDTracks says it's 9216kbps. Same x2 discrepancy.

What am I missing?

On a related note, given that internet radio is generally transmitted using MP3 (lossy), a 'high quality' 320kpbs feed is barely a quarter of a cd's throughput, and a lowly 96kbps feed is a mere 1/15th!

Am I correct in my assertion, or should I go back to reading Janet and John?

Steve

Posted on: 27 December 2012 by spartacus

multiply it by 2 for stereo. Bit rate = (sampling rate) × (bit depth) × (number of channels)

Posted on: 27 December 2012 by intothevoid

bugger

Thanks for the heads-up.

Posted on: 27 December 2012 by winkyincanada

Originally Posted by spartacus:

multiply it by 2 for stereo. Bit rate = (sampling rate) × (bit depth) × (number of channels)

Plus a few bps for "admin"?

Posted on: 28 December 2012 by Simon-in-Suffolk

Winky, no the data rate quoted is just the media/codec data rate and does not include any header, encapsulation data or admin. So the actual data rate is therefore obviously higher than that shown.

Simon