Veo 3.1 vs Gen-4.5

Pick Veo 3.1 when…

• The clip is a final deliverable and 7 extra credits per render is not the constraint
• You are still exploring and need a tight generate-judge-regenerate loop (~75s / 5s clip versus ~90s / 5s clip)
• The clip ships as-is and needs its own synchronized sound
• The brief leans on improved motion

Trade-off: You pay 7 more credits on every generation; You are capped at 8s per clip and will need extension or a cut for anything longer.

Pick Gen-4.5 when…

• You are generating in volume and the 7-credit difference per clip adds up fast
• You have settled on the shot and are rendering the version that ships
• The shot cannot be cut — you need up to 20 seconds in one generation rather than 8
• You are scoring the piece properly and would discard generated audio anyway
• The brief leans on text & image to video

Trade-off: You wait 15s longer per clip; You will handle audio in post.

Vendor angle

These come from different vendors — Google and RunwayML — which is where the interesting differences live. Vendors train on different data and optimise for different failure modes, so the same prompt can produce recognisably different motion, grain and lighting. On FlowAIVideo both sit behind one account and one balance, so you never have to pick a vendor before you have seen the output.

What it costs to decide

Running one clip on each costs 163 credits in total (85 + 78). A new account starts with 40 free credits, which covers Gen-4.5 plus part of the other — enough to run a real comparison rather than reading about one. Paid plans start at 600 credits per month, and there is no per-model subscription: one balance, 22 models.