Video Watermarker
Overlay a text or logo watermark on a video with position, opacity, and size controls, rendered via canvas.
What is Video Watermarker?
A branding tool for adding a channel name, copyright notice or logo to video footage before publishing or sharing a preview.
How it works
The watermark is drawn onto a transparent canvas sized to the video's own resolution — with a drop shadow for legibility — and then composited over the video by ffmpeg's overlay filter. Audio is copied untouched.
- Load your file. Drag a file onto the drop zone or pick one from your device. It is read locally by the browser and never uploaded.
- Set the options. Adjust the handles, format, quality or threshold controls — the preview updates as you change them.
- Process and download. Run the tool, then download the result. Compare the reported before/after size for compressors and converters.
Examples
A 42 MB podcast episode → 9 MB MP3
Trim the intro, normalise to −16 LUFS, and export at 96 kbps mono — a typical interview lands around a fifth of the original size.
A phone video with the wrong orientation
Rotate 90° and the width/height swap in the output, so it plays upright in every player instead of relying on metadata flags.
Common mistakes
Expecting instant encoders
Video encoding runs in single-threaded WebAssembly, so a clip takes roughly its own length (or a little longer) to re-encode. Stream-copy operations are near-instant by comparison.
Re-encoding when a copy would do
Trimming, removing audio and joining same-codec clips can copy streams without re-encoding — pick the copy option when it is offered to avoid any quality loss.
Ignoring the first-load download
The media engine is about 31 MB and is fetched on first use, then cached. The first conversion on a connection is slower than every later one.
Frequently asked questions
Can I add a logo image?
Yes — upload a PNG with transparency in logo mode. Its size follows the same slider, expressed as a percentage of the video height.
Is the watermark burned in permanently?
Yes. The output has the watermark as part of the picture, which is why it survives re-uploads and sharing.
Does applying a watermark re-encode the video?
It must, because the overlay changes every frame. Audio is copied, so only the video is re-encoded.