Why does FLAC-encoded music have varying bitrates?

MasterOfTheWind · 11-17-2008, 02:12 PM

Hi, everyone,

I did not know where to post this so I went for the general forum (mods, if you find a better spot for this thread, please feel free to move it).

Anyways, my question is as following: FLAC is supposed to be a lossless audio format, but I am sort of bewildered as to why my FLAC-files ripped off of the same disc may have widely different bitrates (for example from 702 to 1121). Doesn't that affect quality of playback and doesn't it necessarily mean that some quality is lost?

Also, it seems like different genres may have different mean bitrate: For example classical pieces seem to almost always have a FLAC bitrate of about 500, while say for example heavy metal most prevalently has bitrates of 1000 and up.

Does anyone have a clue as to why this is?

Thanks in advance

irishbitte · 11-17-2008, 03:11 PM

So far as I know, FLAC does not use a specific sampling, but uses what is required to encode the track. That actually can vary throughout the track!

It would not make sense to set one high sampling rate on such an algorithm, since it may not cover every eventuality. E.G., if you are encoding complex heavy metal, it encodes at a higher rate, but if that sample rate was lower than required, FLAC would then not be truly lossless!

lumak · 11-18-2008, 12:14 AM

There isn't any sence in having a high bit rate when there is silence

Either way... as a simple exercise, if you are concerned about that actual 'losslessness' of FLAC..

Code:

flac -8 origianal.wav
flac -d -o copy.wav original.flac
md5sum original.wav
md5sum copy.wav

If the md5sums match then it must be lossless.

Once you are satisfied with that then the major question is... where the hell do you store all those large files.