LigH
7th February 2002, 19:16
Hi everyone!
Somewhere I read lately that AviSynth is no longer developed with effort by its original author, but several people are trying to continue that job. Could someone please clearly tell me the current state of development? I would like to do more with AviSynth in the future, therefore I'm curious what's currently going on in this area.
_
Also, I have some kind of request - I'm probably not able to implement an additional filter by myself easily, maybe someone else has a bit time to try it: I'm using the Levels filter for a gamma correction to spread the TV luminance range to the PC range. A similar functionality would be fine for chroma, because the chrominance saturation range is limited for TV as well.
I played around with the VirtualDub YUV test filters (ExYUVDv / CmYUVDv) and found out that a chrominance saturation enhancement (a result like gamma correction on chroma) can be achieved by applying a contrast function on the U and V components only - unfortunately, this action is quite sensitive: inaccurate correlation between Y and U/V results in green or pink color shifts.
In VirtualDub, the HSI filter by Donald Graft can do such a saturation enhancement, but VirtualDub filters only work in RGB space. Therefore it would be great if someone could write such a filter which can be used in AviSynth, then it can work in YUV space and will be very fast (I guess you would use lookup tables?!). I'm currently thinking about a useful function to use, it reminds me on some kind of Sigmoid (a.k.a. Fermi or Logistic) function of Backpropagation Neural Networks - but maybe there are better or easier ones.
Somewhere I read lately that AviSynth is no longer developed with effort by its original author, but several people are trying to continue that job. Could someone please clearly tell me the current state of development? I would like to do more with AviSynth in the future, therefore I'm curious what's currently going on in this area.
_
Also, I have some kind of request - I'm probably not able to implement an additional filter by myself easily, maybe someone else has a bit time to try it: I'm using the Levels filter for a gamma correction to spread the TV luminance range to the PC range. A similar functionality would be fine for chroma, because the chrominance saturation range is limited for TV as well.
I played around with the VirtualDub YUV test filters (ExYUVDv / CmYUVDv) and found out that a chrominance saturation enhancement (a result like gamma correction on chroma) can be achieved by applying a contrast function on the U and V components only - unfortunately, this action is quite sensitive: inaccurate correlation between Y and U/V results in green or pink color shifts.
In VirtualDub, the HSI filter by Donald Graft can do such a saturation enhancement, but VirtualDub filters only work in RGB space. Therefore it would be great if someone could write such a filter which can be used in AviSynth, then it can work in YUV space and will be very fast (I guess you would use lookup tables?!). I'm currently thinking about a useful function to use, it reminds me on some kind of Sigmoid (a.k.a. Fermi or Logistic) function of Backpropagation Neural Networks - but maybe there are better or easier ones.