flac dev - Nov 2011 - A-law and mu-law

Hi to all!
	I have a database of audio files that I want to losslessly compress.
Unfortunately I have several 8bit A-law and mu-law files in the database 
and I see from here
http://flac.sourceforge.net/documentation_tools_flac.html
that they are not supported by the reference flac encoder/decoder.
Is there a reason for this?
Would it be possible to add support for these files in the reference 
encoder?

Bests,
	Giulio.

Because u-law and a-law are non-linear algorithms and the mathematics of 
FLAC (and AFAIK all lossless encoders) are build for linear PCM. Adding 
these formats would change the FLAC format altogether, decoders are not 
made to work with it (they can only output plain PCM) Best option would 
be converting these files to 16-bit plain WAV and compressing, but I 
guess files won't be much smaller that way. IMO best is to keep them as 
they are.

Op 18-11-11 12:34, Giulio Paci schreef:
> Hi to all!
> 	I have a database of audio files that I want to losslessly compress.
> Unfortunately I have several 8bit A-law and mu-law files in the database
> and I see from here
> http://flac.sourceforge.net/documentation_tools_flac.html
> that they are not supported by the reference flac encoder/decoder.
> Is there a reason for this?
> Would it be possible to add support for these files in the reference
> encoder?
>
> Bests,
> 	Giulio.
>
> _______________________________________________
> Flac-dev mailing list
> Flac-dev at xiph.org
> http://lists.xiph.org/mailman/listinfo/flac-dev

Hi Martijn,
	thank you for your answer. So the problem would be suboptimal
compression due to suboptimal assumption about the input signal, right?
What I do not understand is how the format of a FLAC format would be
affected by supporting A-law and mu-law files as input (and thus
output). Despite of suboptimal performance, is it possible to treat 8bit
*-law samples as 8bit linear PCM files and write down the original
format information in the output while decoding?

For my needs converting them to 16bit linear PCM is an option, but I
will need to keep track of the original format outside the file, which
is something that I would prefer to avoid. I would prefer to avoid
having multiple file format around (I mean containers format here) if
possible. Do you know of any container that supports both flac and *-law
streams?

Thank you again.
Bests,
	Giulio.

Il 18/11/2011 19:13, Martijn van Beurden ha scritto:
> Because u-law and a-law are non-linear algorithms and the mathematics of 
> FLAC (and AFAIK all lossless encoders) are build for linear PCM. Adding 
> these formats would change the FLAC format altogether, decoders are not 
> made to work with it (they can only output plain PCM) Best option would 
> be converting these files to 16-bit plain WAV and compressing, but I 
> guess files won't be much smaller that way. IMO best is to keep them as
> they are.
> 
> Op 18-11-11 12:34, Giulio Paci schreef:
>> Hi to all!
>> 	I have a database of audio files that I want to losslessly compress.
>> Unfortunately I have several 8bit A-law and mu-law files in the
database
>> and I see from here
>> http://flac.sourceforge.net/documentation_tools_flac.html
>> that they are not supported by the reference flac encoder/decoder.
>> Is there a reason for this?
>> Would it be possible to add support for these files in the reference
>> encoder?
>>
>> Bests,
>> 	Giulio.
>>
>> _______________________________________________
>> Flac-dev mailing list
>> Flac-dev at xiph.org
>> http://lists.xiph.org/mailman/listinfo/flac-dev
> 
> _______________________________________________
> Flac-dev mailing list
> Flac-dev at xiph.org
> http://lists.xiph.org/mailman/listinfo/flac-dev
> 
>