Kling vs Runway for Image-to-Video: i2v, Motion, Cost

If you're animating a still image and weighing Kling against Runway, the honest answer is that they're not symmetric choices: Kling is hosted behind the Aigenway gateway with per-second USD billing, Runway is not, and that one fact drives most of the rest of the comparison. Here's how the two actually compare on i2v quality, motion and cost — and how to reach Kling (plus Veo and Seedance) from the same key.

What each one is actually good at

Runway's Gen-4 line is known for tight prompt adherence on stylized and VFX-heavy shots, and Act-One for performance-capture face transfer — a genuinely distinct feature nothing on this gateway reproduces exactly. Kling's strength sits elsewhere: fluid, physically plausible motion on image-to-video specifically, and a dedicated Motion Control mode that transfers a reference video's movement onto your character instead of hoping a text prompt describes the right motion. If your brief is "animate this product shot or character art believably," Kling is the stronger default; if it's "I need Act-One's exact face-swap trick," nothing here substitutes for that one feature, and you'd keep a Runway account for it.

The i2v request, side by side

Because Kling sits on the gateway's shared task contract, the image-to-video call looks identical to every other model you'd run here — same fields Runway would ask for conceptually (an image, a motion prompt, a duration), just one consistent shape instead of a provider-specific SDK:

curl -X POST https://api.aigenway.com/v1/generations \
  -H "Authorization: Bearer sk_live_..." \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
    "provider": "kling",
    "model": "kling-v2-master",
    "method": "image_to_video",
    "params": {
      "prompt": "slow push-in, rain streaking down the window behind her, cinematic",
      "input_image": "https://example.com/scene.png",
      "duration": 5
    }
  }'

Confirm the live model code for your account before hardcoding it — list what's active with GET /v1/methods?provider=kling rather than trusting a string from any blog post, this one included.

Motion control vs text-only re-rolling

This is where the comparison stops being close. Runway's text-prompt motion is strong but still a guess-and-check loop — you describe the camera move and re-roll until it lands. Kling's motion_control method takes a reference video plus your character image and transfers the reference's actual motion onto the character, which is a different category of control for repeatable choreography, mascot performances, or a dance/gesture you need to hit exactly:

curl -X POST https://api.aigenway.com/v1/generations \
  -H "Authorization: Bearer sk_live_..." \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
    "provider": "kling",
    "model": "kling-motion-control",
    "method": "motion_control",
    "params": {
      "input_image": "https://example.com/character.png",
      "reference_video": "https://example.com/dance-reference.mp4"
    }
  }'

Nothing on the gateway claims to replicate Act-One's face transfer, but if the actual requirement is reusable, predictable motion rather than a specific face-swap effect, Motion Control covers more ground than re-rolling a Runway prompt. Details and parameter limits are in the Kling video guide.

Cost per second and billing model

Runway runs on its own credit packs, which you buy and forecast in advance; Kling on this gateway runs on prepaid USD billed per second of output, read directly from the API instead of estimated from a credits dashboard. Kling also spans multiple tiers — a Standard tier for drafts up through Master for cinematic fidelity — so you can match spend to the shot instead of paying a flagship rate for every clip. Exact per-second pricing shifts as providers update their lineups, so pull current numbers from /v1/methods before budgeting a production run rather than relying on a fixed table here. If cost predictability and per-request pricing you can query programmatically matter more than a single Runway-exclusive feature, that alone tips the comparison toward the gateway.

Where this leaves Veo and Seedance

Kling isn't the only i2v option once you're off Runway — the same gateway, same key, same task contract also reaches Veo 3 (native audio generated with the picture) and Seedance (fast, cheap iteration for drafts and volume). Switching providers mid-project is a one-line change to provider/model, not a rewrite:

curl "https://api.aigenway.com/v1/methods?provider=veo" \
  -H "Authorization: Bearer sk_live_..."

The response, status values and webhook signature are identical across Kling, Veo and Seedance, which is the part a Runway-only account can't offer: one integration that lets you compare image-to-video output across three independently-trained models on your own footage, not a demo reel. See the task lifecycle docs for the full async flow.