Unifying Mixed Resolutions: Scaling Order and Algorithm Choice
Footage from three phones and a screen recording arrives in every resolution. Stitch as-is and the frame jumps; publish as-is and it looks uneven. Two minutes of unification makes every later step smoother.
Pick the target: round down
The rule is "unify to the lowest common tier" (usually 720p for mixed sources). Upscaling 720p to 1080p only grows the file — the picture carries no new information. Upscaling adds no detail; that is the physical boundary of scaling.
Choose by purpose: publishing to short-video platforms targets 1080p (most source is already there; mild upsampling of a stray 720p is acceptable); stitching targets the lowest tier to avoid frame jumps; archives keep each file at native resolution. Four target heights: 480p, 720p, 1080p, 2K.
The algorithm choice
The three algorithms differ at edges: Lanczos preserves edges best — the first choice for downscaling; Bicubic is balanced and safe for general use; Bilinear is fastest but slightly soft — for rushed jobs or already-soft sources.
Downscaling removes information, so algorithm differences are modest though Lanczos still wins; upsampling invents information, where algorithm differences show most — and since none of them create real detail, avoid upsampling altogether. Vertical clips inside a landscape sequence need cropping first: scaling cannot fix orientation, only crop can unify composition.
Batch order: scale first, compress second
The correct batch sequence: scale everything to the unified resolution, then compress. Scaling is the biggest size lever (pixel count changes quadratically), and scaling first means exactly one encode pass — one quality tax. Reversing the order compresses twice.
After unification, spot-check three things: resolutions all match, orientation is consistent, and clarity is acceptable (focus on the original 480p sources). Then stitching or publishing starts from a guaranteed-consistent baseline.