Troubleshooting
Black preview, export errors, slowness and missing media — what to do.
5 min
Editing video in a browser asks a lot of your computer: decoding, effects, audio and export all happen right here, on this machine. So odd things do happen now and then. Almost all of them have a known cause and a simple fix.
Read through the sections below — chances are your situation is on the list. And most importantly: your files are never uploaded anywhere and never lost, so take your time working through this.
The preview is black — no picture
The video imported fine, the duration is right, you can even hear the sound — but where the picture should be there's nothing but black. This is not a problem with your file, and it isn't a bug in the studio either.
Here's why it happens: on some computers (usually Windows machines with an old or faulty graphics driver) the browser's hardware video decoder — the part that unpacks frames using the graphics card — simply doesn't work. The file is fine, the browser is fine; one link in the chain is broken.
The only cost is speed: a CPU is slower than a graphics card, so the preview may feel a little heavier and exports take longer. You can work perfectly well like this. If you want a permanent fix, you can turn off graphics acceleration in your browser's settings or update your graphics driver — click the badge and the studio will walk you through it. But none of that is required.
Export trouble
Export doesn't work in Safari
Safari doesn't yet fully support the browser features needed to assemble an mp4. Do your export in Chrome or Edge instead — bear in mind projects live inside the browser you made them in, so you'd be rebuilding the edit there.
Firefox: the audio came out as Opus
Export does work in Firefox, but the sound is written with the Opus codec rather than AAC. Most players and social platforms read that just fine. If some older program opens the file without audio, redo the export in Chrome or Edge.
Export is very slow
Every single frame is redrawn, has its effects applied, and is recompressed. A long or 4K project taking several minutes is normal. To speed it up: pick a smaller height (1080p instead of 4K), export only the range you need with I/O, and close other heavy apps while the tab stays open.
The export stopped halfway
Usually the tab got closed or the computer went to sleep. Don't close the tab while exporting. You'll get a push notification when it's finished, so you can work in another window — just leave the tab open.
I reopened the project — the media is gone
When you reopen a project you may see a message saying some media files couldn't be found, and a few clips have vanished. To understand why, remember one thing: the studio uploads nothing to a server — the files you import are stored inside your own browser. That's excellent for privacy, but it comes with conditions.
- Browser data was cleared. “Clear site data” or wiping your history takes the media with it.
- Incognito / private mode. Everything there disappears the moment the window closes. Do real work in a normal window.
- A different browser or a different computer. A project lives in the browser it was made in; it doesn't travel.
- The disk filled up. When space runs out, a browser may quietly evict what it has stored.
The app feels slow
If the preview stutters, dragging feels sticky or the cursor lags behind, your machine is simply running out of headroom. The following almost always helps.
Close the other tabs
Other heavy pages — video, maps, twenty open tabs — are competing for memory and CPU. Give the browser room while you edit.
Add effects last
Blur, chroma key and color grading are recomputed on every frame. Finish the edit itself — the cuts, the order, the rhythm — and worry about the look afterwards.
Shrink huge files beforehand
Editing a 4K or 60 fps source at 1080p makes everything noticeably lighter, and the final quality is decided by your export settings anyway.
Reload the page
After a long session the browser's memory gets clogged. Your work is saved automatically, so go ahead and hit
F5— nothing will be lost.
Frequently asked
The video imported but there's no thumbnail. Should I worry?
No. That's usually the hardware-decode issue again: the picture couldn't be grabbed, but the file itself was read correctly and edits just fine. Preview and export both come out normally via software decoding.
The exported video has no sound.
Check the tracks first: is the audio track muted, is another track soloed, is the track volume at zero? If you can hear it in the preview you should hear it in the export — the same calculation runs both. And if you exported from Firefox, the audio is in the Opus codec, which some older programs can't read.
Where is my project stored? Is it uploaded anywhere?
Nowhere. Both the project and its media stay in your browser's own storage, on your machine. That's why the studio works offline — and why clearing your browser data deletes the project too.
Can I edit on a phone?
You can review and make small tweaks, but for real editing use a computer: memory is tight in a mobile browser, and exporting a long project is heavy going.
None of this helped. What now?
Reload the page (your work is saved). If that doesn't do it, try opening the project in an up-to-date Chrome or Edge — those are the browsers the studio is tested against first.