[Flac] Is FLAC hardware independent?

[Brian Willoughby]

FLAC is a format which guarantees lossless data preservation.  FLAC  
does not guarantee a specific or consistent compression ratio.  If  
you are looking for a guarantee that the compression ratio is  
repeatable, then you are looking in the wrong place.

While it is probably true that the same executable will produce the  
same FLAC file from the same source file on different PCs, I'm not  
sure there isn't any run-time variation based on processor type.

A better approach for you would be to modify your expectation to be  
that the compression ratios fall into a range of values, rather than  
expect them to be precise.  Keep in mind that FLAC is focused on  
guaranteeing that the final uncompressed audio samples precisely  
match the original audio samples, while secondary concerns such as  
the intermediate compression ratio are not guaranteed at all.  You  
might be able to find repeatable experiments, but it does not change  
the fact that FLAC does not have a pre-defined compression ratio.

Brian Willoughby
Sound Consulting


On May 23, 2011, at 09:46, Eri Eri wrote:
> I’m investigating together with Fernando Marengo, and I think our  
> doubt might have been misunderstood.
> Let’s say that we have a certain version of  Flac (1.2.1 for  
> example) and a certain track (“The blue room.wav” for example). If  
> we were to compress that same track on different PCs using exactly  
> the same Flac executable and command line parameters, would we  
> always get exactly the same (bit-by-bit) output file?
>
> Differences in the output files yield different compression ratios.  
> We want to make sure our results are consistent and repeatable so  
> answering that question is crucial.