Can 720p 50fps be converted back to 1080i?

[VideoFanatic]

Can it be done to get back the original 1080i picture without any negative effects?

[Skiller]

Can it be done to get back the original 1080i picture without any negative effects?

Without adding any additional negative effects, yes. If the video has been badly deinterlaced to obtain 720p, you cannot undo this.


From 720p to 1080i in AviSynth is almost a no-brainer.

Spline36Resize(1920,1080)

AssumeTFF()
SeparateFields().SelectEvery(4,0,3).Weave()

[jagabo]

The result won't be exactly the same as your original 1080i source. It will be less sharp (especially the chroma) and will contain any deinterlacing artifacts you introduced when you downscaled.

[newpball]

Can it be done to get back the original 1080i picture without any negative effects?

What do you mean by get "get back"?

What happened to the original?
Did you cut the resolution in half and now you want it back?

Then that is obviously not possible.