Anything better for upconverting than Lanczos4?

[brassplyer]

From looking around under the topic of upconversion I see Lanczos4 recommended.

Is there a method of resizing/upconverting that you feel is clearly and obviously superior to this?

[Selur]

nnedi3_rpow2 for upscaling by a power of 2 + resizer of your choice for downsizing to the resolution you want,...

[pandy]

I prefer Spline over Lanczos (all windowed Sinc based resizers introduce ringing).

[jagabo]

There is no single resizer that is best for everything.

[SameSelf]

When it comes to upscaliing there are at least half a dozen good ones to choose from. And as jagabo said, it will depend on your footage especially how detailed it is. As a tip, the pros who do this for a living never use the one size fits all approach. They will customize the filters for each scene. Check out the Avisynth page on scalers and spend time getting familiar with each one. Just be sure when you are testing you are doing so on a quality display or TV otherwise you will be flying blind.