How to add a transparent corner watermark online
- Step 1Open the watermark engine — Open the watermark engine. It's a Pro tool (£7/month); the free tier shows an upgrade overlay.
- Step 2Drop your video — Drop one clip. The picker takes
video/*plus.mp4,.mov,.mkv,.webm,.avi,.m4v,.ts. Output is H.264 MP4. - Step 3Add a transparent PNG — In the Image row, choose a PNG that already has a transparent background. That transparency is what makes the corner overlay look native instead of boxed.
- Step 4Pick the corner — Set Position to the corner you want:
tl,tr,bl, orbr(default). Avoidcenterfor a corner overlay — it ignores margin and sits in the middle of the frame. - Step 5Set the inset margin — Set Margin (px) (0–200, default 24). It insets the logo from both edges of the chosen corner; raise it to keep clear of rounded phone corners or platform UI.
- Step 6Tune opacity and scale, then export — Set Opacity (0–1) (default 0.6) and Scale (0.05–0.5) (default 0.15) — 0.08–0.12 is typical for a corner badge. Run it and download the MP4.
Corner anchors and their overlay expressions
Each corner maps to a specific FFmpeg overlay position built from the margin (m). Centre is shown for completeness but isn't a corner.
| Position value | Corner | Overlay expression | Honours margin? |
|---|---|---|---|
tl | Top-left | m:m | Yes |
tr | Top-right | W-w-m:m | Yes |
bl | Bottom-left | m:H-h-m | Yes |
br (default) | Bottom-right | W-w-m:H-h-m | Yes |
center | (centre, not a corner) | (W-w)/2:(H-h)/2 | No — ignores margin |
Transparency behaviour by file type
Why PNG is the right choice for a clean, box-free corner overlay.
| File type | Has alpha? | Result in the corner | Recommendation |
|---|---|---|---|
| PNG (transparent) | Yes | Only the logo shape shows; no box | Recommended |
| PNG (opaque) | No transparent pixels | Solid rectangle of the image | Add transparency in your design tool |
| JPEG | No (format has no alpha) | Solid rectangle incl. background colour | Convert to transparent PNG |
| SVG | Yes (if it rasterises) | Box-free if it renders; may fail in-engine | Export to PNG for reliability |
Cookbook
Corner-overlay recipes — the four corners and the margin/opacity choices that make each one look intentional.
Clean bottom-right corner badge
The default corner with a small, semi-transparent badge — the everyday look for a branded clip.
Settings: Image = logo.png (transparent) Position = br Opacity = 0.6 Scale = 0.12 Margin = 24 Filter built: [1:v]format=rgba,colorchannelmixer=aa=0.600,scale=iw*0.120:-1[wm]; [0:v][wm]overlay=W-w-24:H-h-24
Top-left badge with a generous inset
A larger margin keeps the logo well clear of the edge — useful when the footage has busy content near the corners.
Settings: Position = tl Opacity = 0.7 Scale = 0.1 Margin = 48 Filter built: [1:v]format=rgba,colorchannelmixer=aa=0.700,scale=iw*0.100:-1[wm]; [0:v][wm]overlay=48:48
Proof the overlay has no background box
If a watermark shows a rectangle, the source image isn't transparent. The fix is the file, not the tool — the engine honours PNG alpha.
Symptom: white/black box around the logo in the corner Cause : the PNG has opaque pixels (or it's a JPEG) Check : open the PNG on a coloured background in any viewer Fix : re-export the logo with a transparent background
Keep the badge off a phone's rounded corner
Vertical video on phones clips the very corners. Bump the margin so the badge stays fully visible.
9:16 clip on a phone with rounded corners: Margin 12 -> badge edge can be clipped Margin 36 -> badge stays fully inside the safe area Position = br, Margin = 36
Same corner badge across resolutions
Because scale is a fraction of width, one setting gives a matching corner badge on every export size.
Scale = 0.1 720p -> 1280 * 0.1 = 128px badge 1080p -> 1920 * 0.1 = 192px badge 4K -> 3840 * 0.1 = 384px badge Margin is in pixels, so raise it proportionally on 4K if needed.
Edge cases and what actually happens
Watermark shows a background box
Source file issueA visible rectangle means the source image has opaque pixels — it's a JPEG or a non-transparent PNG. The engine honours alpha via format=rgba; re-export the logo with a transparent background to fix it.
`center` chosen for a corner overlay
ExpectedThe center anchor sits the logo in the middle of the frame and ignores the margin. For a corner overlay, pick tl, tr, bl, or br.
Badge clipped by a phone's rounded corner
ExpectedVertical clips on phones mask the literal corners. A small margin can let the badge get clipped — raise the margin (e.g. 36–48) to keep it inside the visible area.
Margin larger than the frame allows
ExpectedA very large margin combined with a large scale can push the logo toward the opposite edge or off-frame. Reduce the margin or scale if the badge isn't where you expect.
SVG logo doesn't render
Possible failureFFmpeg.wasm SVG rasterisation is build-dependent and may fail or come out blank. Export the SVG to a transparent PNG at the badge size first.
Opacity multiplies existing transparency
By designIf your PNG is already partly transparent, the opacity value scales it down further (alpha × opacity). Export at full opacity if you want the engine's setting to be the only transparency applied.
Output is always MP4
By designAny input container exports as H.264 MP4. The corner overlay requires a re-encode, so the original codec isn't preserved.
No video re-scaling
PreservedThe overlay does not change the video's resolution or frame rate — only a logo is composited on top. The badge scales; the footage doesn't.
Free tier blocked
Pro requiredThe watermark engine is minTier: pro. The free tier sees the upgrade overlay; Pro (£7/month) unlocks it with a 10 GB per-file ceiling.
Frequently asked questions
Why does my corner watermark have a box around it?
Because the source image isn't transparent — it's either a JPEG (which has no alpha channel at all) or a PNG whose 'background' pixels are actually opaque. The engine honours transparency via format=rgba and blends with overlay, so a properly transparent PNG composites with no box. Re-export the logo with a transparent background and the rectangle disappears.
How do I choose which corner?
Set the Position control to tl, tr, bl, or br. Each maps to a tested overlay expression (e.g. br is W-w-margin:H-h-margin). Bottom-right is the default. Don't use center for a corner overlay — it sits in the middle and ignores the margin.
What does the margin do?
It insets the logo from the edges of the chosen corner, in pixels (0–200, default 24). A bottom-right logo at margin 24 sits 24px from both the right and bottom edges. Raise it to keep the badge clear of rounded phone corners or platform UI.
How big should a corner badge be?
Scale 0.08–0.12 (8–12% of video width) is the typical corner-badge range. Scale is a fraction of width, so the same value stays proportional across resolutions — set it once and reuse it.
Does opacity replace or multiply the PNG's transparency?
It multiplies. The opacity value (0–1) is applied with colorchannelmixer=aa, scaling the watermark's existing alpha. A fully opaque PNG at opacity 0.6 shows at 60%; a half-transparent PNG at 0.6 shows at ~30%. Export at full opacity if you want this control to be the only transparency applied.
Is this really online with no install?
Yes — it runs in your browser tab via FFmpeg.wasm. There's nothing to install, and nothing uploads: the video and the logo are processed locally on your machine.
What's the output format?
H.264 MP4 at CRF 20, with audio stream-copied. The corner overlay requires a re-encode of the video, so the output is always MP4 regardless of the input container.
Can I put the watermark in two corners at once?
No — one watermark at one position per pass. To brand two corners, run the tool twice: watermark once for the first corner, feed the result back in, and watermark again for the second.
Will the overlay change my video's resolution?
No. Only the watermark is scaled and composited; the video keeps its original resolution and frame rate.
Can I use an SVG logo for the corner?
You can select an SVG, but FFmpeg.wasm's SVG support is build-dependent and may fail or render blank. For a reliable transparent corner overlay, export your SVG to a PNG at the badge size first.
Will the badge get clipped on vertical phone video?
It can if the margin is too small, because phones round and mask the very corners. Use a margin around 36–48 on 9:16 clips to keep the badge fully inside the safe area.
Can I do a batch of corner overlays at once?
Yes — drop several clips and the client batches them with the same corner, opacity, and scale (Pro 5, Pro + Media 50, Developer unlimited). See the batch watermark guide.
Privacy first
Every JAD Video tool runs entirely in your browser via WebCodecs and FFmpeg (WebAssembly). Your video files never leave your device — verified by zero outbound network requests during processing.