[FFmpeg-devel] Question: indeo5 scalability DWT

[Michael Niedermayer]

On Tue, Jun 02, 2009 at 10:38:11PM +0200, Maxim wrote:
> 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?

looks pretty much like the standard wavelet, except that its scaled by
a -1/2 factor ...

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
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