Case study: stock b-roll vs AI b-roll on the same script

Case study: stock b-roll vs AI b-roll on the same script

A 'productivity tips' channel needed b-roll. We built 10 Shorts twice: once with free Pexels clips, once with Runway-generated AI b-roll.

Result: no retention difference (within 1%). But production time differed wildly — Pexels stack: 6 min/short. Runway: 22 min/short (prompting, re-rolls, upscaling).

Pros (Runway):
— Unique visuals competitors can't grab
— Good for abstract concepts with no stock match

Cons:
— 4x slower, occasional warped hands
— Credits drain on re-rolls

Price: Pexels free / Runway $15 mo (limited credits).

Verdict: for tips content, free stock won on time with no view penalty. Use Runway only when no real footage exists.