AW: [Flac-dev] Incomplete format description?

[Josh Coalson]

--- Tor-Einar Jarnbjo <Tor-Einar_Jarnbjo at grosch-link.de> wrote:
> > -----Ursprungliche Nachricht-----
> > Von: Josh Coalson
> >
> > --- Tor-Einar Jarnbjo <Tor-Einar_Jarnbjo at grosch-link.de> wrote:
> > > Hi,
> > >
> > > have I just overseen a link, or is the format description on
> > > http://flac.sourceforge.net/format.html lacking information on
> how to
> > > actually decode the residual partitions to PCM sample data?
> >
> > you are correct, it is not explicit enough.  the encoded residual
> > is a string of Rice codes of the form 000nnn, where 000 is a unary
> > portion and nnn is the binary portion of length k, k being the
> > rice parameter.  but there is a signed->unsigned transform before
> > rice coding that needs to be documented.
> 
> Is this something you are working on, and expect to be ready in the
> near
> future? I took a quick look at the libFLAC sources, but the OO-like
> implementation and pointer-shuffling is not very easy to understand.

yes, I will probably get to it soon after the release.
the encoding side is pretty convoluted but for decoding,
src/libFLAC/stream_decoder.c:read_residual_partitioned_rice_()
should be pretty straightforward once you ignore the
FLAC__SYMMETRIC_RICE stuff (which is not used).  feel free to
ask questions about it here.

> The reason I am asking is, that I've started to implement a FLAC
> decoder for
> the Java Media Framework

cool, that was on my TODO list but way way down.  I'm glad
you're doing it :)

Josh


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