How to Upscale and Smooth AI Video Output

Increase resolution and frame rate of a generated clip so it looks crisp on big screens.

8 minIntermediate

Visit Runway

Most AI video models export at 720p and a modest frame rate. For a hero clip on a website or a high-quality upload, you will want more resolution and smoother motion. This guide covers both the built-in upscalers in Runway and Kling and a free ffmpeg fallback.

What you need

A finished clip from Runway, Kling, or Veo
Credits if using a built-in upscaler
ffmpeg installed for the free path (brew install ffmpeg)
About 8 minutes

Step 1: Try the built-in upscaler first

Both Runway and Kling offer a one-click upscale on a finished clip. Runway calls it Upscale in the clip menu; Kling exposes a higher-resolution export in Pro mode. These are tuned for AI footage and usually beat generic tools, so try them before anything else.

Runway - Upscale

forest_dawn.mp4 1280x768

------------------------------------------------------------

[ Download ] [ Extend ] [ *Upscale to 4K* ]

Estimated credits: 100 Output: 3840x2304

The upscale option in a finished clip's menu.

Step 2: Upscale with ffmpeg as a free fallback

If you are out of credits or want full control, ffmpeg can scale a clip with a high-quality filter. The lanczos algorithm gives a sharper result than the default. This will not invent detail like an AI upscaler, but it cleanly enlarges the frame.

upscale.sh

ffmpeg -i input.mp4 -vf "scale=1920:-2:flags=lanczos" \
  -c:v libx264 -crf 18 -preset slow -pix_fmt yuv420p \
  output_1080p.mp4

Step 3: Smooth motion by interpolating frames

To turn choppy motion into smooth 60fps, ffmpeg's minterpolate filter generates intermediate frames. It is slow, so run it on short clips, and check for artifacts on fast motion where interpolation can warp.

zsh - frame interpolation

$ffmpeg -i output_1080p.mp4 -vf "minterpolate=fps=60:mi_mode=mci" smooth_60.mp4

frame= 300 fps= 12 q=-1.0 ...

expect this to run several times slower than playback

Watch for interpolation artifacts

Frame interpolation can smear around fast edges and limbs. If you see ghosting, drop the target fps to 30 or skip interpolation on that clip and keep the original frame rate.

Step 4: Compare before and after

Play the original and the processed file side by side. The upscaled version should be sharper on a large screen, and the interpolated version should have visibly smoother pans. If the AI upscaler result looked better, keep it and skip the ffmpeg path.

Result

A 720p generated clip becomes a 1080p or 4K file with smoother motion, suitable for a website hero or a high-quality upload. Trying the model's own upscaler first saves time, with ffmpeg as a reliable free backup.