[Vorbis-dev] improving vorbis compression with arithmetic coding
and by exploiting temporal redundancies
dbalatoni at programozo.hu
Fri Sep 2 01:05:41 PDT 2005
csütörtök 01 szeptember 2005 23.06-kor Dimitry Andric ezeket a bolcs
gondolatokat fogalmazta meg:
> On 2005-09-01 at 23:07:18 Yann Guidon wrote:
> > If it was known in advance, then the efforts were fruitless.
For me it was not known in advance - and probably the exact degree of the
suitability of mdct for said purpose was not widely studied. AAC too has
temporal prediction in the standard (and it is AFAIK much simpler).
> > Implementing arithcodes is an easy and effective method.
> However, isn't arithmetic coding encumbered with numerous patents?
> This might have been the reason that it was never used in Ogg
Yes it is said to be patent encumbered, but the reason why huffman and vq was
used is in my humble opinion computational complexity. Arithmetic coding
could be substituted with range coding (very similar, but old enough not to
be patent encumbered), but it is almost as computationally intensive afaik.
And as it seems vq and huffman performs well.
> There are probably lots more interesting and useful compression
> improvents that could be added, if only they weren't patented by the
> large media corporations (e.g. Philips, Thomson, etc.)
Yes, just read the AAC standard.
What kills me, doesn't make me stronger.
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