[FFmpeg-devel] Question: indeo5 scalability DWT

Maxim max_pole
Tue Jun 2 22:38:11 CEST 2009

Hello guys,

I'm working on the last step of the indeo5 scalability feature that uses
a DWT for performing subband decomposition/recomposition.
The recompostion code used in the decoder need some understanding
(because of optimizations) that's why I've started on the encoder side
(decomposition) first.

So far the wavelet used for decomposing looks like the well-known
5/3-LeGall wavelet. The coefficients for the low-pass filter match the
ones used in JPEG2000 and snow:

{h0} = {-1, 2, 6, 2, -1}1/8

But the high-pass filter coefficients don't match:

{h1} = {1, -2, 1}1/4

My question: could anybody skilled in wavelets (Michael?) clarify me
this situation? Is that a modification of the LeGall wavelet or a
completely different 5/3 one?


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