What does adjusting a video do?

Adjusting a video changes how its picture looks without changing what's in it. A clip filmed in a dim room can be made brighter, a flat and washed-out one can get more contrast, dull colors can be made richer, and any clip can be turned black and white. These are the same basic color corrections photo apps offer, applied to every frame of the video.

Tool description

This tool adjusts the brightness, contrast, saturation, and hue of a video in your browser. Choose a video, move the sliders, and watch the preview change as you go, then save the adjusted video as an MP4. Nothing is uploaded: the video is processed on your device with FFmpeg compiled to WebAssembly.

Features

  • Brightness from -100% (black) to +100% (twice as bright)
  • Contrast from -100% (flat gray) to +100% (twice the contrast)
  • Saturation from -100% (black and white) to +100% (twice as colorful)
  • Hue from -180° to 180°, turning every color around the color wheel
  • The preview and the timeline thumbnails show the changes live, and the saved video matches them
  • Type exact values, double-click a slider to reset it, or reset everything at once
  • Saves as MP4 with H.264 video and AAC audio, which plays almost everywhere

How it works

The preview uses the browser's own CSS filters, so it updates instantly while you drag. When you save, FFmpeg applies the same math to every frame: brightness multiplies each color channel, contrast pushes each channel away from or toward middle gray, and saturation and hue mix the red, green, and blue channels with the matrices the CSS standard defines. The adjustments are applied in the order the sliders are listed. The video is then encoded again as H.264, and the sound is kept.

Tips

  • For a dark video, raise Brightness a little and Contrast slightly so the picture doesn't look foggy.
  • Large brightness or contrast changes clip highlights and shadows to pure white or black, and that detail can't be brought back. Small steps usually look best.
  • Set Saturation to -100% for a black and white video.
  • Re-encoding in the browser is slower than in a desktop app, so long or high-resolution videos can take several minutes.
  • The first run downloads FFmpeg, about 30 MB. Later runs on the same page start right away.