Automatically Resize a Video

[EHarlen]

Is it possible to automatically resize a video at a resolution below 1080p to 1080p video using AviSynth while preserving the aspect ratio?

For example; 640x480(4:3) to 1440x1080(4:3) or 1280x720(16:9) to 1920x1080(16:9)

[Selur]

target_h = 1080
target_w = int(float(Width) / Height * target_h / 2) * 2  # *2 to keep even number
Lanczos4Resize(target_w, target_h) # or whatever resizer you prefer

should work, assuming a 1:1 PAR(=pixel aspect ratio) and that the output resolution needs to be mod2.

[EHarlen]

Thanks.