[theora-dev] Used base quantizer towice

Timothy B. Terriberry tterribe at email.unc.edu
Wed Feb 13 00:27:32 PST 2008

Asanka Dilruk wrote:
> Hi all,
>    In the theora codec, The bace quantizer matrices(matrices for golden
> frame and matrix for inter frame) are defined twice. The same matrix
> initialize twice. why is that? pls help me.....

The base matrices are interpolated over a range of qi values. The two
matrices are the values to use at the start and end of the range. Since
they are the same, this yields a constant matrix, in accordance with the
design of VP3. This may change in future versions of the encoder, since
it is well known that the relative importance of high frequency
coefficients is very different near the visibility threshold than far
above it.

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