Features
Video upscaler
Upscale videos 2× or 4× using a fast single-pass ffmpeg Lanczos scaler — fully in-browser, no upload required. Queue multiple files and retry any that fail.
Video Upscaler
The video upscaler increases video resolution 2× or 4× using a single-pass ffmpeg Lanczos scaler — a high-quality algorithm that produces sharp results without the softness of bicubic interpolation. All processing runs locally in your browser.
Accessing the tool
Navigate to /video-upscale or click Video Upscaler in the header tools menu.
Choosing a scale
2× Upscale — Doubles resolution in each dimension. A 960×540 video becomes 1920×1080. This is the recommended option for most clips.
4× Upscale — Quadruples resolution. A 480×270 video becomes 1920×1080. Ideal for old, low-resolution footage. Note: the input must be ≤ 1024px on the longest side (a 1920px input would produce 7680px output, exceeding the maximum supported output size).
Supported formats
Upload MP4, WebM, MOV, AVI, MKV, MPEG, M4V, or OGV files. Maximum file size: 200 MB.
Processing time
Processing time depends on clip duration, source resolution, and your device's CPU. Rough estimates:
| Clip length | 720p source | Notes |
|---|---|---|
| 10s | 30–60s | Fast GPU |
| 30s | 2–5 min | Mid-range laptop |
| 60s | 5–10 min | Near the duration limit |
The maximum clip duration is set in the site configuration (typically 120 seconds). Longer clips should be trimmed before upscaling.
Output format
Upscaled video is exported as WebM (VP9) — a widely supported, efficient format. Download from the queue card when processing is complete.
Queue
You can add multiple clips to the queue and they will process sequentially. While a clip is processing you can continue adding more files. The current clip must finish before the next begins.
Use the × button on a queue card to remove a clip. Completed clips show a green Download button.
Dimension limits
| Input resolution | 2× output | 4× output |
|---|---|---|
| 480×270 | 960×540 | 1920×1080 |
| 960×540 | 1920×1080 | 3840×2160 |
| 1280×720 | 2560×1440 | 5120×2880 |
| 1920×1080 | ✓ accepted | ✗ too large (4× cap is 1024px) |
If the output would exceed the maximum supported dimensions (typically 8192px), the upscaler will display an error before starting. Downscale the source clip first or switch to 2×.
How it works
The upscaler runs a single-pass ffmpeg Lanczos scaler implementing the Lanczos kernel — a high-quality reconstruction filter that preserves edge sharpness and avoids the ring artefacts of simpler methods. The clip is decoded, rescaled in one pass, and re-encoded into the output stream.
Troubleshooting
"Video encoding produced no data" — This usually means the clip was too short (< 1 second) or the selected codec isn't supported by your browser. Try a different browser or a longer clip.
"Source image could not be decoded" — The output resolution exceeded the maximum supported dimensions. Switch to 2× scale or downscale the source first.
Processing is very slow — Lanczos scaling is CPU-bound. On slower machines, a 30-second 1080p clip can take several minutes. Close other heavy apps if possible.
Output looks soft — This is expected for highly compressed source video. The upscaler can only recover detail that exists in the source; heavily compressed clips may still look soft at 4×.