[FFmpeg-devel] 4xm idct computation

[yann.lepetitcorps at free.fr]

> > > > More precisely, I search an encoder/decoder that work like the DCT/iDCT
> but
> > > with
> > > > the De Haar, Debauchies and/or others lifting schemes transforms
> instead
> > > the
> > > > [Fast] Fourrier Transform

> > >
> > > look at dirac, snow, indeo4/5 and jpeg2000 they use things in that
> > > direction. most are not block based though
> > >

> >
> > This is my problem, I search something that is "only partially block based"
> :)
> > (cf. that work on fixed 8x8 blocs, but where the blocs are dynamically
> > constructed from a "mipmapped" picture)


> indeo4 uses block based haar transform amongth other things
> see http://wiki.multimedia.cx/index.php?title=Indeo_4
>
> the haar transform does not perform very well though.
>
>
> and there are fraktal coders that work by downscaling a simple trivial
> image and then using blocks from it to construct a new image repeatly
> to build up the image one wants.
> These are too slow for practical use though.

Thanks,

This seem a good scheme, but what is the scale of the "too slow" ?

If this need something like an 10x increase speed or less, this can certainly to
be implemented in a "short" time :)

But if this need something more like an 100x or 1000x increase (or even more)
this seem effectively really more hard to make ...


@+
Yannoo