[vorbis-dev] patents and separate entropy coding
segher at wanadoo.nl
Fri Dec 15 19:25:51 PST 2000
Lourens Veen wrote:
> Roger, sorry 'bout that. I am talking about patent claim #US5579430
> which is entitled Digital encoding process and can be found at
This is the main MPEG patent, right? I'm very pleased about this patent,
as it is too specific :-) It doesn't embody my mp3 encoder.
> It patents "A digital encoding process for transmitting and/or storing
> acoustical sigs and, in particular, music signals, in which scanned
libvorbis doesn't transmit and/or store. Of course, all sensible
applications will :-(
> values of the acoustical signal are transformed by means of a
> transformation or a filter bank into a sequence of second scanned
> values, which reproduce the spectral composition of the acoustical
This is very disputable in case of a MDCT filter bank. The output
of a MDCT filter bank only has _half_ of the spectral information
about that particular block, and so surely can't reproduce it. And
if you're talking not about a block, but about the entire stream: in
that case it's not a transformation, nor a filter bank.
> signal, and the sequence of second scanned values is quantized in
> accordance with the requirements with varying precision and is partially
"With the requirements" doesn't say anything. No requirements were mentioned.
You can't claim anything you don't mention. And it's argueable for any
serious psycho-acoustic encoder, that it quantizes with _equal_ precison,
not varying precision.
> or entirely encoded by an optimum encoder, and in which a corresponding
Neither the mop3 Huffman tables, nor the Vorbis VQ tables implement
> decoding and inverse transformation takes place during the
Prior art (and at least two prior patents, as well).
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