Re:Show HN: Download any song without knowing its name
by pherq on Thursday October 08, 2015 @07:08PM
(#10357025)
That has nothing to do with the bitrate -- the fact that you're getting a different unit on your 192 should be in an indication (bits or bits/frame, as opposed to kilobits/second).
CDs store audio as 16 bit samples, with 44100 samples per second. This gives a bitrate of 16 bits * 44100 Hz = 705600 bits/second (705.6 Kbps). This is per channel, so the total bitrate of the format is 1411.2 kbps, as stated (modulo rounding) by the GP.
EDIT: in fact, the article you link specifically says (a couple sections further down) that the bitrate is 1411.2 kbps.
Re:Show HN: Download any song without knowing its name
by omribahumi on Friday October 09, 2015 @04:05AM
(#10358717)
This means CDs should have ~800MB of usable space. Why only 700MB?
705600 * 2 = 1411200 # bits/s for stereo channel
80 * 60 = 4800 # seconds in 80 minutes
1411200 * 4800 = 6773760000 # bits in a 80 minutes CD
6773760000 / 8 / 1024 /1024 = 807 # In MB
Each audio sample is a signed 16-bit two's complement integer, with sample values ranging from −32768 to +32767. The source audio data is divided into frames, containing twelve samples each (six left and right samples, alternating), for a total of 192 bits (24 bytes) of audio data per frame.
https://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio#Dat...