mp3 File Size

Posted By: padrino

mp3 File Size - 03/18/08 12:13

Hello,

does anyone here know whether there is a certain formula, with which one could calculate an estimated file size of an mp3 File? (given would be the length and the bitrate of the file...)
Posted By: sPlKe

Re: mp3 File Size - 03/18/08 12:34

depends on the compression rate.
with 128kbps its usually 1:10 to a wave (+- 2mb)
the higher the compression rate (192kbps is what i use) the higher the filesize
Posted By: Xarthor

Re: mp3 File Size - 03/18/08 12:50

Not sure but for me the mp3 files are 1mb per minute (playtime) with a bitrate of 128kbps.
If you only take the bitrate 128 kilo-bit-per-second, divide it by 8 (to get kilo-byte-per-second) and multiply it with 60 (one minute) you get 960 kilo-byte.
So I guess 1mb (1024KB) for 1 minute is a good estimation.

Correct me if I'm wrong.
Posted By: padrino

Re: mp3 File Size - 03/18/08 20:00

Quote:

Not sure but for me the mp3 files are 1mb per minute (playtime) with a bitrate of 128kbps.
If you only take the bitrate 128 kilo-bit-per-second, divide it by 8 (to get kilo-byte-per-second) and multiply it with 60 (one minute) you get 960 kilo-byte.
So I guess 1mb (1024KB) for 1 minute is a good estimation.

Correct me if I'm wrong.




I do not know, I may have gotten this wrong, but the bitrate is not constant within a single track. At least that is what I read on wikipedia...
Posted By: Joey

Re: mp3 File Size - 03/19/08 15:54

for vbr, that's true. not for cbr.
Posted By: padrino

Re: mp3 File Size - 03/19/08 16:21

Quote:

for vbr, that's true. not for cbr.




alright, now you got me all confused xDD
Posted By: Joey

Re: mp3 File Size - 03/19/08 16:30

vbr = variable bitrate, cbr = constant bitrate

these terms define how the bitrate varies over the compressed binary. mp3 supports both methods and additionally abr (average bitrate) which means that the bitrate varies over e.g. the song but the average is at a specific level.
Posted By: padrino

Re: mp3 File Size - 03/19/08 17:26

is there a version that is more often used than the other one? or are they both common?
Posted By: Joey

Re: mp3 File Size - 04/01/08 15:19

they're both common. vbr gives you better quality. some very old mp3-players can't play vbr encoded files, but you don't need to care about them anymore nowadays.
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