[Flac] best params for safe archiving, 192kHz no-lax and w64 support

[Josh Coalson]

--- Marek Peteraj <marpet at naex.sk> wrote:
> On Sat, 2004-10-09 at 22:41, Josh Coalson wrote:
> > --- Marek Peteraj <marpet at naex.sk> wrote:
> > > Also i'd like to ask whether a no-lax 192kHz mode is planned in
> flac,
> > > seems like 192kHz isn't directly supported although flac can
> compress
> > > such rate in lax mode.
> > 
> > no, it's a limitation of native FLAC.  if the only reason to
> > use --lax is for 192kHz, the files will still be streamable
> > but some hardware players may not support a sample rate that
> > high.
> 
> It would be cool to have a native 192kHz support since it will become
> the standard in consumer audio in a few years i believe and it's a
> heavily used samplerate in studios these days. Is it possible to add
> 192kHz while retaining backwards compatibility or would it break the
> current specs?

no, it would break slightly.  maybe no one would notice since
not many people are using 192kHz stuff.  also, 192kHz is a bit
too much demand to place on all h/w makers.  96kHz is pushing
the limit of what low-power devices can decode using straight
libFLAC.

using --lax just for 192kHz will not inhibit the file from
being streamable or usable in any other way that a subset file
is, except if a player cannot handle 192kHz to begin with.

> A theoretical/technical question - what are the differences between
> meridian lossless packing(MLP) used in DVD-A and FLAC? From the
> technical point of view, would it be possible to replace MLP with
> FLAC
> or are there any technical hurdles?

MLP is proprietary, not much is publically known about it.

'replace' is a little too general.  FLAC cannot be used on a
DVD-A disc because it's not part of the spec.  MLP also has a
rate limiting feature.  some people believe that you can always
rate limit with MLP and still be lossless when this is actually
not mathematically possible; OTOH FLAC is always lossless.

aside from that I think FLAC could be used to encode anything
that MLP can.

> > > My last question - is there any chance for flac to support w64
> files?
> > > That would be cool since it would allow to compress >2Gb files.
> > > (not sure if flac can compress >2Gb raw files) 
> > > See http://www.mega-nerd.com/libsndfile/ for reference.
> > 
> > never heard of w64 before now.  if it's close to WAVE it's
> > more likely.  is there a spec?
> 
> Unfortunately no, the only source for specs is the abovementioned
> link,
> the libsndfile library supports reading and writing of w64 files in
> various resolutions.

using libsndfile may be an option, I'll make a note of it.

Josh



		
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