Find Every Scene Cut in a Video
Upload a video and the detector walks through it, finds where one shot ends and the next begins, and gives you a numbered list of scenes with a start time, an end time, and a thumbnail for each. It runs in the browser by comparing frames, so the video never leaves your device and there is no app to install.
This is the mechanical job, splitting a video at its cuts, not an AI guessing what the video is about. If you need a cut list to start editing, a way to jump to each shot, or a quick count of how many scenes a clip has, this is the tool for that.
What a Scene Detector Actually Does
A scene cut is the moment the picture changes from one shot to another. Detecting them turns a single video file into a list of segments you can act on, and that list is the thing most editing and captioning workflows actually need first.
Worth being precise about the words, because search results mix them up. A shot is one continuous run of camera between two cuts. A scene is usually several shots that belong together. Frame-difference detection like this finds shots, the hard visual boundaries, which is what “scene cut detection” and “shot boundary detection” both point at in practice. It does not read the story to decide where a narrative scene begins, that is a judgment call no automatic tool makes reliably.
How It Finds the Cuts
The method is deliberately simple, which is why it can run on your own machine with no server. The tool samples the video at a steady step, shrinks each sampled frame down to a tiny grayscale thumbnail, and measures how different each frame is from the one before it. A hard cut makes almost every pixel change at once, so the difference spikes. When that spike crosses the sensitivity threshold, the tool marks a cut there and opens a new scene.
Because it samples rather than checking every single frame, a cut lands on the nearest sample, so a timecode can be off by a fraction of a second on a long video. That is the trade for keeping it fast and in the browser. For an edit list or a rough segmentation it is close enough, and you can see each boundary in its thumbnail to confirm it.
The sensitivity control is the knob that matters. High catches subtle changes and returns more scenes, low only breaks on big changes and returns fewer. Start on Medium, then move it if the count looks too high or too low for the footage.
Hard Cuts, Fades, and What Gets Missed
Hard cuts are what this does well. A straight edit from one shot to another shows up clearly because the frame difference jumps.
Gradual transitions are the honest weak spot. A slow fade to black, a cross dissolve, or a long morph changes the picture a little at a time, so no single frame-to-frame difference is large enough to trip the threshold. Raising the sensitivity helps, but a soft dissolve can still read as one continuous scene. Fast motion or a hard camera flash can push the other way and split one shot into two. The thumbnails are there so you can spot and ignore a false split at a glance.
None of this is a defect unique to browser tools. Frame-difference detection has these limits everywhere. What you get here is a fast, private first pass that is right on the great majority of ordinary cuts.
Browser Tool vs DaVinci and PySceneDetect
The two tools people usually reach for are DaVinci Resolve and PySceneDetect, and both are good at more than this. The question is what you are willing to set up.
DaVinci Resolve has a scene cut detection feature, but it means installing a large editing suite and importing the clip before you can run it. PySceneDetect is an open-source command-line tool with content-aware and threshold modes, which is powerful if you are comfortable in a terminal and installing Python packages. Neither is something you open for one quick check on one clip.
This tool is the no-install, no-account version for exactly that quick check. You drop a file in, read the cut list, copy the timecodes, and move on. For a heavy batch job or frame-perfect boundaries inside a finished edit, the desktop tools still win, and that is a fair place to send you.
Who Uses Scene Detection
Editors use a cut list to break raw footage into clips before assembly, or to find the exact seconds where B-roll changes so they can drop in music or captions on the beat.
Captioning and subtitling work benefits because a subtitle file reads better when lines break on shot changes instead of running across a cut. A scene list gives you those break points.
People logging or archiving footage use it to index a long recording by shot, so a two-hour capture becomes a navigable list instead of a scrub bar. And anyone comparing two versions of an edit can count scenes and check the cut points quickly.
Beyond the Cut List
Once you know where the scenes are, the next step is usually to do something with them. To understand what is inside each scene rather than just where it cuts, the AI video analyzer reads the content, objects, and events with timestamps. To pull a still image at a specific moment or on an interval, the video frame extractor saves frames as PNG or JPG. And if your question is whether a clip was AI-generated or manipulated rather than where it was cut, that is the AI video detector, a different job entirely.
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FAQ
What is video scene detection?
It is finding the points where a video cuts from one shot to the next, then splitting the video into a list of scenes at those points. This tool does it by comparing frames and marking where the picture changes sharply, and it gives you a timecode and a thumbnail for each scene.
Is the scene detector free?
Yes. Uploading a video and detecting its scenes runs entirely in your browser at no cost, with no account and no watermark. The AI features that go further, like analyzing what is in each scene, follow ScreenApp’s normal plan.
Does it work online without installing anything?
Yes. It runs in the browser, so there is nothing to download or install, on desktop or phone. Unlike DaVinci Resolve or PySceneDetect, you do not set up an app or a command line first.
How is this different from AI video analysis?
Scene detection is mechanical: it finds the cuts by frame difference and does not interpret content. AI video analysis reads what happens in the footage, the objects, actions, and moments, and describes them. Use this for a cut list, and the AI video analyzer when you need to know what the video contains.
Can it detect fades and dissolves?
Not as reliably as hard cuts. A slow fade or cross dissolve changes the frame gradually, so it can read as one continuous scene. Raising the sensitivity catches more of them, but a very soft transition may still be missed. Straight cuts are detected well.
Is my video uploaded anywhere?
No. The whole analysis happens on your device with the browser’s own canvas. The file is read locally to compare frames, and nothing is sent to a server, stored, or logged.
What video formats does it support?
Any format your browser can play, which covers MP4, MOV, WebM, and most AVI files. If the video plays in the page, the detector can sample and analyze it.
Is this a free alternative to DaVinci scene cut detection or PySceneDetect?
For a quick, one-off check it is. It uses the same frame-difference idea without the install or the command line. For frame-perfect boundaries inside a full edit, or large automated batches, the desktop and command-line tools are still the better fit.
