[Flac-dev] Blocking and compression.

Wayde Milas wmilas at rarcoa.com
Wed Jan 21 06:36:02 PST 2004


On Tue, 2004-01-20 at 23:44, Josh Coalson wrote:
> Miroslav did some experiments with searching for optimum blocksize.
> from what I remember it made at best a couple percent difference.
> there was a thread about it here a while back.
> 
Did his changes make it in? I can think of a coupla ways to approach
this and I'd like to hear about what he tried.

A couple of % doesnt seem like much, but considering that flac is
lossless, a couple of % here and there adds up to a big savings.

> 
> you can get very close ot arithmetic coding with range coding,
> which is much faster and believed to be patent free.  monkey's
> audio uses range coding as part of its entropy coder.  I did
> some experiments and couldn't get much of a compression
> improvement, but the area is far from exhausted.
> 

I was not aware that arithmetic coding was patented anywhere. The texts
I have on the subject don't mention a patent, although that doesn't
surprise me. I had considered range coding, but arithmetic is superior
in every was except for speed. Having a nice reference encoder that you
could then go back to and compare ordered rice or range to I thought
would be ideal.

Speaking of, I'd be curios as to what texts your recommend on lossless
compression. If you are interested, when I get home later today I can
tell you what I've read through and what I found worthwile. Lossless
compression has always been a hobby for me and I have no formal training
on the subject, so anything I can find to read is a great help.

I heard that Monky's released source a while back. I'll browse around
and take a look at his stuff when I get a chance.

Wayde





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