flac dev - Sep 2005 - question regarding compression %

Hi,
For those of you who don't know, I now have an application on pocket pc
using flac. Live2496 does realtime encoding while recording. Live2496 typically
is used to record a digital source using the Core Sound PDAudio device. Links
are now on the main flac page if you are interested in learning more.
 
I have a question. We have run across a 24-bit file that when we record it, flac
level zero compression only results in about a 2% reduction in the file size. I
use flac level zero because we don't have the computing power required for
(higher level flac) realtime encoding on pocket pc's and windows CE.

What is it about a file that would cause such a poor encoding rate?

A couple of observations:
Rectangular waves seem to encode at about 55-60% of the original size.
Muted digital sources seem to take up very little space.

Gordon Gidluck
http://www.gidluckmastering.com/live2496.html

--- Gordon Gidluck <gidluck@alltel.net> wrote:
> Hi,
> For those of you who don't know, I now have an application on pocket
> pc using flac. Live2496 does realtime encoding while recording.
> Live2496 typically is used to record a digital source using the Core
> Sound PDAudio device. Links are now on the main flac page if you are
> interested in learning more. 
>  
> I have a question. We have run across a 24-bit file that when we
> record it, flac level zero compression only results in about a 2%
> reduction in the file size. I use flac level zero because we don't
> have the computing power required for (higher level flac) realtime
> encoding on pocket pc's and windows CE. 
> 
> What is it about a file that would cause such a poor encoding rate?
hard to tell without a sample.  or you could decode and reencode
the sample on another machine with -1 .. -8 switches and post
the compresses sizes, that could also give a clue.

if there's no way to do -1 on the pocketpc (which is equivalent
to -0 -M and will help with stereo), there are a couple of
tweaks you can try that shouldn't affect the encoding time but
might help for hi-res recording.  you could try increasing the
blocksize with -b.  -0 defaults to -b 1152, try 2304 and 4608.

also -0 defaults to -r 2,2; you could try other values like
1,1 3,3 4,4 ...  increasing -r tends to work better with larger
blocksizes.

what kind of CPU is in it?

Josh



		
__________________________________ 
Yahoo! Mail - PC Magazine Editors' Choice 2005 
http://mail.yahoo.com