How to batch-watermark a folder of videos
- Step 1Open the watermark engine on Pro or above — Open the watermark engine. Batch needs a tier whose batch limit is above 1 — Pro (5), Pro + Media (50), or Developer (unlimited). The free tier can't run the tool at all.
- Step 2Drop multiple videos at once — Drop more than one file. The dropzone allows multiple selection when your tier's batch limit exceeds 1, and the client enters batch mode automatically once there's more than one file.
- Step 3Set the shared watermark and settings — Pick the Image and set Position, Opacity, Scale, and Margin once. These same values apply to every file in the batch — there is no per-file override.
- Step 4Start the batch — Run it. The client calls the batch runner, which loops over the files and processes them one at a time through the same watermark pipeline.
- Step 5Watch the per-file progress — Each file shows queued → processing → done (or error). Because it's sequential, total time is roughly the sum of the individual encodes.
- Step 6Download the branded set — Collect each finished MP4 as it completes. A failed file reports its error and the batch continues with the next one.
Batch limits by tier
Real per-tier batch counts and per-file size ceilings for the video family, from the tier-limits code. Durations are unbounded — only file size and batch count are limited.
| Tier | Batch files | Per-file size limit | Watermark engine access |
|---|---|---|---|
| Free | 1 | 1 GB | No — Pro-only tool (upgrade overlay) |
| Pro (£7/mo) | 5 | 10 GB | Yes |
| Pro + Media | 50 | 100 GB | Yes |
| Developer | unlimited | 100 GB | Yes |
How batch mode actually runs
Behaviour of the batch runner for the watermark engine — set expectations correctly.
| Aspect | Behaviour |
|---|---|
| Trigger | Auto-enabled when files dropped > 1 and the tool isn't a multi-input tool |
| Concurrency | Sequential — one file at a time (FFmpeg.wasm is a single instance) |
| Order | Files process in the order they appear in the list |
| Settings | One shared watermark image + one set of options for the whole batch |
| Per-file output | Each file produces its own H.264 MP4 (audio stream-copied) |
| Error handling | A failing file reports its error; the batch continues with the next |
| Cancel | Cancels the current run and marks remaining queued files as cancelled |
Cookbook
Batch-watermark recipes for branding many clips at once with a single logo and consistent placement.
Brand a course's lesson exports
Forty lesson recordings, one course logo, same corner on each. Drop them all, set once, walk away.
Drop : lesson-01.mp4 ... lesson-40.mp4 (Pro + Media: up to 50) Set : Image=course-logo.png, Position=br, Opacity=0.6, Scale=0.1 Runs sequentially: lesson-01.mp4 processing -> done lesson-02.mp4 processing -> done ... (one at a time) lesson-40.mp4 processing -> done
Same brand, mixed source containers
A batch can mix MOV, MKV, and MP4 sources — each is re-encoded to its own MP4 with the same watermark.
Inputs : clip-a.mov, clip-b.mkv, clip-c.mp4 Shared : Image=logo.png, Position=tr, Opacity=0.7, Scale=0.1 Outputs: clip-a.mp4, clip-b.mp4, clip-c.mp4 (all H.264, audio copied)
One file fails, the rest finish
A truncated download in the middle of a batch won't stop the others — its error is reported and the queue continues.
clip-1.mp4 -> done clip-2.mp4 -> error: Watermark composite failed: ... clip-3.mp4 -> done clip-4.mp4 -> done Re-fix clip-2 and re-run it on its own.
Estimating batch time
Because it's sequential, total time is roughly the sum of per-file encodes — plan accordingly for big sets.
Each 1080p clip ~ 40s to watermark on this machine 10 clips -> ~ 6-7 minutes total (sequential) 50 clips -> ~ 33 minutes total Keep the tab open; the batch needs the page alive to run.
Why one logo per batch (and how to handle two brands)
A batch shares a single watermark image and settings. For two different logos, run two batches.
Brand A clips -> batch 1 with logo-a.png Brand B clips -> batch 2 with logo-b.png There is no per-file logo override within a single batch.
Edge cases and what actually happens
Free tier can't batch (or even run) the tool
Pro requiredThe watermark engine is Pro-only (minTier: pro) and the free batch limit is 1. Batch requires Pro (5), Pro + Media (50), or Developer (unlimited).
Dropped more files than the tier allows
RejectedThe dropzone enforces the tier's batch limit. Exceeding it (e.g. 6 files on Pro's limit of 5) is blocked — split into multiple batches or upgrade.
Batch runs sequentially, not in parallel
ExpectedFFmpeg.wasm is a single instance, so files process one at a time in list order. Total time is the sum of the individual encodes, not the longest one.
One file fails mid-batch
ContinuesA failing file reports its error (e.g. a corrupt source or composite failure) and the runner moves on to the next file. Finished files keep their results.
Cancelling a running batch
CancelledAborting marks the current and all remaining queued files as cancelled. Already-completed files are unaffected and stay downloadable.
A single file exceeds the size limit
RejectedEach file is checked against the per-file ceiling (Pro 10 GB, Pro + Media / Developer 100 GB). An oversized file is rejected; the rest of the batch can still proceed.
One shared watermark for the whole batch
By designA batch uses a single watermark image and one set of options. For different logos per clip, run separate batches.
Closing the tab kills the batch
ExpectedProcessing runs in the page, so closing the tab or navigating away ends the batch. Keep the tab open and the machine awake until it finishes.
Mixed input containers in one batch
SupportedMOV, MKV, WEBM, and MP4 sources can be mixed; each is re-encoded to its own H.264 MP4 with the same watermark applied.
Frequently asked questions
How do I start a batch?
Just drop more than one video. When your tier's batch limit is above 1, the dropzone allows multiple selection and the client automatically enters batch mode once there's more than one file. Set the watermark and options once, then run — they apply to every file.
How many videos can I watermark at once?
It depends on your tier: Pro processes up to 5 files per batch, Pro + Media up to 50, and Developer is unlimited. The free tier's batch limit is 1, and the watermark engine isn't available on free anyway (it's a Pro tool).
Does the batch process files in parallel?
No — it's sequential. FFmpeg.wasm runs as a single instance, so files are watermarked one at a time, in the order they appear. Total time is roughly the sum of the per-file encode times, so plan accordingly for large sets.
Can each video have a different logo or position?
No — a batch shares one watermark image and one set of settings (position, opacity, scale, margin) across every file. For two different brands or layouts, run two separate batches.
What happens if one file fails?
The runner reports that file's error and continues with the next one — a single corrupt or oversized input doesn't abort the whole batch. Finished files keep their downloadable results; just re-run the failed one on its own.
Can I cancel a batch partway through?
Yes. Cancelling stops the current encode and marks all remaining queued files as cancelled. Any files that already completed keep their results and stay downloadable.
Does batching upload my videos?
No. Every file in the batch is composited locally in your browser via FFmpeg.wasm. Nothing is uploaded, which is why a whole archive can be branded privately.
Will batch re-encode the audio on each file?
No — audio is stream-copied (-c:a copy) on every file in the batch, so you brand a whole set with no audio re-encode anywhere.
What output do I get from a batch?
Each input produces its own H.264 MP4 (CRF 20), regardless of its source container. You download each branded MP4 as it finishes.
Do all files need to be the same resolution?
No. Scale is a fraction of each video's width, so the same scale setting gives a proportional watermark on every clip even if resolutions differ. Margin is in pixels, so very mixed resolutions may want a margin that suits the smallest frame.
Can I leave it running and do something else?
Yes — that's the point of batch mode. Keep the browser tab open and the machine awake; closing the tab or sleeping the machine ends the batch. Each file updates its status as it goes.
Is there a different tool if I need one watermark per clip?
No separate tool — just run the single-file flow per clip, or run multiple small batches grouped by logo. For one brand across a folder, this batch flow is the fastest path. See the main watermark guide for the single-file controls.
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.