[Bf-vfx] Improving the 2D stabilization tool :: Next Steps

[Ichthyostega]

Am 08.06.2014 15:25, schrieb Sergey Sharybin:
> internally all the stabilization values are to be stored in normalized
> [0..1] space in order to be re-applied for the proxied movie. For the
> interface they might be relatively easily converted to pixel space.

of course, but can you then animate (add keyframes) on those values displayed
in pixel space, yet still have the data in the keyframe in normalised coords?

> Wouldn't mind having feedback from Sebastian as well.


IMHO this topic is of some relevance, because -- if we want to do things
properly -- the pivot point must become part of the stabilisation data.
Otherwise we will never get a clean design, esp. when it comes to nodes.

The part *applying* the transformation must be (and is indeed currently)
separate from the part which *measures* the stabilisation data. Thus
the whole data feed needs to be explicit.

Right now we have (translation[2], angle, scale)

What we need at least is (translation[2], pivot[2], angle, scale)
As extension, we could consider to add a shear / trapezoid component,
simply because these are the missing parts to complete an affine-linear
transformation.

I fully agree with you that we do not want to compensate lens distortions.
But these shear/trapezoid movements are not due to lens errors, but due
to perspective and tilting of the camera. If you want to do masking and
rotoscoping, then for sure you want those shear/trapezoid movements
compensated to. If you go just for a stabilised image, these remaining
movments are quite annoying too


A nasty concern regarding the components in the stabilisation data is
that they are used as cache key. We should reconsider this part too,
maybe change the cache to store just a hash of the parameters?

Cheers,
Hermann