[Flac-dev] Non-audio applications

Daniel O'Connor doconnor at gsoft.com.au
Tue Nov 19 22:52:03 PST 2002

On Wed, 2002-11-20 at 16:56, Josh Coalson wrote:
> In every case I've ever seen, default FLAC compresses more
> than default shorten.  The anomaly here is due to the number
> of channels; it appears that you really do have 300 uncorrelated
> channels of data (uncorrelated according to the linear predictor
> I mean).  FLAC only supports 8 channels, but I would bet that
> the compression would be a lot better if you separated the 300
> channels stream into several streams (<=8 channels each) and
> compressed them with FLAC.  That may not be practical for your
> application.

Hmm, well it would be a bit of a pain :)
Might be an interesting thing to try though.

> > I needed the --lax otherwise it generated a
> Yes, by default the encoder tries to encode according to a subset
> of parameters that makes for easier decoding.  You need --lax to
> turn that off.

Ahh, I see.

> You could try splitting the signal like I mentioned.  It might
> take some experimenting to find channel combinations that have
> some exploitable correlation.  See the format page for the kinds
> of inter-channel and intra-channel decorrelation FLAC does, it
> might give you some more ideas:

OK, the format description explains a bit more.

Thanks :)

Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
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