a 640x360 screen recording becomes blurred in a 720p project that is rendered to 640x360

Hi,
how can I prevent that a 640x360 (360p) screen recording video (mpeg4) becomes blurred in a 720p (1280x720) project that is rendered to 640x360? - I need 720p videos (no screen recordings) in the timeline for some effects (crop, zoom, ..).

tia
Eckard

It is normal for an up-interpolated image to look blurry, but is it still blurry after rendering back down to 640x360? There shouldn't be much difference from the 640x360 original, especially if the interpolation ratio is exactly 1:2.
Well, if you zoom/crop, the ratio won't be exactly 1:2 anymore, and the quality of the interpolator will become important.

So, if you just import 640x360 into an 720p project, and then render out to 640x360, without applying any effects, zooms or crops, how does the result compare to the original?
If it is blurred, then there is a problem in MLT's interpolation - with an exact 1:2 scaling, the result should be perfect even with the simplest nearest neighbor interpolator.

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