Hello everyone

I was wondering, what kind of interpolation kdenlive is using when effects like rotation or zoom are employed ?

I ask that because the result of these effects seems very blurry, like the result of a bilinear filter. And when I extract one frame of my video and rotate it using a bicubic filter, the result is way more sharp. It makes a great difference between sequence with and without rotation or zoom (very visible to the naked eye and no need to press stop and examine the frame).

So if kdenlive uses the bilinear filtering, is it possible to implement something like bicubic or lanczos ?

I dunno what type of interpolation it uses. But I belive that the different effects in the crop and transform group http://userbase.kde.org/Kdenlive/Manual/Effects/Crop_and_transform use different methods. So I think that you might find that you get different results depending on if you use Rotate (keyframable) or Rotate and Shear. Also note that the Affine Transition also gives the opportunity to rotate the image and it might give you a different result too.

at the moment it is still not clear. Google brought me to this thread.
For example - a screenshot of another popular GNU-program