FLAC file below 320 kbps?

[Bykhoff]

How come some FLAC files that I've ripped from purchased CDs using the least amount of compression result in files that are smaller than 320 kbps?
 
 
 
 
Thank you.

 

[RRod]

  How come some FLAC files that I've ripped from purchased CDs using the least amount of compression result in files that are smaller than 320 kbps?
 
 
 
 
Thank you.

 
A 1kHz sine wave for me compresses to a smaller file size as FLAC than as 320k MP3. I assume whatever material you have must also be something that FLAC is relatively good at compressing.

 

[MindsMirror]

Quiet audio is easier for a lossless algorithm to compress. At the extreme end of that spectrum, silence can be compressed very easily.
 
It is easier to compress stereo channels that are highly correlated, meaning the recording is mostly mono.
 
Audio that is simple with little varying frequency content tends to be easier for the algorithm to predict, and therefor easier to compress. The opposite end of that spectrum is white noise, which is entirely random and saturates the entire frequency range and cannot be compressed at all.
 
Your <320Kbps tracks probably have one or more of these properties.

 

[Bykhoff]

Thank you. Yes, you probably right.
 
It's a CD of classical music compositions for the piano. The tracks' bitrate range from 260 kbps to 502 kbps. Probably since it's a modern studio recording, the silences are truly silent and quite compressed.