Flac - Oct 2004 - best params for safe archiving, 192kHz no-lax and w64 support

Hi all,

i'd like to ask what the best options are for safe 24bit 96kHz
archiving. Currently i'm only using -8 but there are also some other
options like block size etc. Can anyone suggest? 

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.

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.

Marek

--- Marek Peteraj <marpet@naex.sk> wrote:
> Hi all,
> 
> i'd like to ask what the best options are for safe 24bit 96kHz
> archiving. Currently i'm only using -8 but there are also some other
> options like block size etc. Can anyone suggest? 
I haven't heard of anyone using FLAC for 192khz, so you'll
probably just have to experiment.  when you have some results,
let me know so I can tune the defaults better.

for high sample rates, tweaking -b and -r (and to a lesser extent
-l) is important

for high resolutions (24bit), -l, -e, -p, -q are relevant.
> 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.
> 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?

Josh



		
_______________________________
Do you Yahoo!?
Declare Yourself - Register online to vote today!
http://vote.yahoo.com

Hi Josh, 

On Sat, 2004-10-09 at 22:41, Josh Coalson wrote:
> --- Marek Peteraj <marpet@naex.sk> wrote:
> > Hi all,
> > 
> > i'd like to ask what the best options are for safe 24bit 96kHz
> > archiving. Currently i'm only using -8 but there are also some
other
> > options like block size etc. Can anyone suggest? 
> 
> I haven't heard of anyone using FLAC for 192khz, so you'll
> probably just have to experiment.  when you have some results,
> let me know so I can tune the defaults better.
> 
> for high sample rates, tweaking -b and -r (and to a lesser extent
> -l) is important
> 
> for high resolutions (24bit), -l, -e, -p, -q are relevant.
Thanks for the suggestions, i will do some tests and report.
> 
> > 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?

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?
> 
> > 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.

AFAIK the only difference should be a 64-bit value for data length, but
i'll let you know if i know more.

Marek

> 
> > 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?
Erik de Castro Lopo, the author of libsndfile told me that there are
other differences aswell such as all chunk markers being 16 bytes
instead of 4 bytes and all chunk lengths being uint64_t instead og
uint32_t. That raises a question, why not use libsndfile for input files
in flac? :)
That would enable to process WAV, AIFF, BWF and W64 which would be
impressive.

Marek