Resize a local video to a target pixel width and/or height while preserving aspect ratio. Frames are scaled on a canvas and re-encoded with MediaRecorder.
When to use it
- Downscale 4K screen recordings for Slack or email
- Match a platform's maximum upload resolution
- Reduce pixel count before further compression
How it works
Enter width, height, or both (use 0 on one axis to scale by the other). The helper computes proportional dimensions, draws each frame scaled to the canvas, and records the stream without audio.
Example
Resizing 1920×1080 to width 960 yields a 960×540 output clip.
Limitations
- Upscaling cannot invent detail; prefer downscaling for quality
- Canvas re-encode removes audio tracks
- Browser encoding speed limits practical length on low-end devices