[Flac] flac filesize limitation

[Brian Willoughby]

On May 12, 2007, at 16:23, Harry Sack wrote:
> is there a filesize limitation for flac files because of the encoder
> or decoder for some reason?

The maximum number of samples in a FLAC stream is 64 GigaSamples.  It  
would be impossible to convert such files with any other format  
besides CAF.  In other words, FLAC supports longer audio recordings  
than every existing file format except (Apple) CAF.

FLAC allows up to 8 channels and can theoretically support 32-bit  
samples, which would represent a 2 TeraByte file when uncompressed.   
However, the available encoders for FLAC are limited to 24-bit  
samples, which would be equivalent to a 1.5 TeraByte uncompressed file.

The actual FLAC files will be smaller since they are compressed, but  
pure noise sources will result in a FLAC file that is the same size  
as the uncompressed data.  I rather doubt that any natural recording  
would approach pure noise performance, since there is so much  
correlation between transmission channels.

If we ever reach this 64 GigaSample limit, the fact that FLAC is a  
stream should allow multiple FLAC headers to be concatenated in a  
single file - although that might be tricky.  I doubt we'll have  
issues any time soon.

Brian Willoughby
Sound Consulting