[vorbis-dev] video codec

[Holger Waechtler]

On Fri, 9 Feb 2001, Gregory Maxwell wrote:

> On Sat, Feb 10, 2001 at 12:03:34AM +0800, Steve Underwood wrote:
> [snip]
> > Your useless data may not be mine. Years of DSP have taught me that I
> > can predict only 80-90% of the outcome. The other 10-20% can be a
> > killer! Don't wait too long to find out.
> [snip]
> 
> For example, in my testing with 3d transforms, I found temporal ghosting to
> be a big problem at sudden scene changes (I suspect because we have so
> little temporal resolution compaired to spacial resolution and the
> thresholding doesn't concentrate power in depth-space sufficently to cope
> with the low resolution these). Perhaps we need to generalize SET
> to 3d so we can clamp the depth of a transform to non-power of two sizes
> with frame level granularity, then detect scene changes and chop the
> transform.

I didn't used a SET but reduced the order of wavelets at boundaries. The
problems of ghost images arise already in the current code. I want to
reduce the offset between bitplanes in frame-direction child levels, hope
this will reduce the artifacts. Let's see ...

However, if we have a couple of test cases and a set of scripts which
compresses the sequences and then measures distortion, DC offsets etc.
and generates (semi-)automatic quality reports (perhaps a MSNR/PSNR per
frame graph), we don't really have to care about the number of test cases.
The more, the better.

- Holger

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