FFmpeg Scene Detection ? Find Cuts Automatically

Q: What threshold should I use for scene detection?

`gt(scene,0.4)` flags significant cuts. Lower to 0.3 for fast-cut content, raise to 0.5 to catch only hard cuts and ignore camera moves.

Q: How do I export the timestamps to a file?

`ffmpeg -i in.mp4 -filter:v "select='gt(scene,0.4)',showinfo" -f null - 2> scenes.log` then grep for `pts_time`.

Q: Can I split the video at every detected scene automatically?

Yes — feed the timestamps into a wrapper script that calls `ffmpeg -ss A -to B -c copy partN.mp4` per detected range.

What You’ll Learn

How to detect scene changes with the scdet filter
How to tune detection sensitivity via threshold (t)
How to read per-scene timestamps from the filter metadata
How to extract a frame at each scene boundary using select
How to batch-generate thumbnails at every cut

Tested with: FFmpeg 6.1 (ubuntu-latest / CI verified)
Platform: Windows / macOS / Linux

Basic Command

ffmpeg -i input.mp4 -vf "scdet=t=10" -f null /dev/null

-f null /dev/null skips writing an output file and prints detection info to stderr.

Reading the Output

[scdet @ 0x...] lavfi.scd.score: 18.3, lavfi.scd.time: 4.96
[scdet @ 0x...] lavfi.scd.score: 32.7, lavfi.scd.time: 23.42

Field	Description
`lavfi.scd.score`	Scene-change score (higher = larger change)
`lavfi.scd.time`	Timestamp of the detection (seconds)

Tuning `threshold`

Parameter	Default	Description
`t` / `threshold`	`10`	Scores at or above this value are reported as scene changes

ffmpeg -i input.mp4 -vf "scdet=t=20" -f null /dev/null

Low value (e.g. 5): Detects small changes (more false positives)
High value (e.g. 40): Detects only clear cuts (more missed cuts)
Documentaries and films: 10–20 is a reasonable starting point

Save a Frame at Every Scene Change

Combine with the select filter to save a still at each cut.

ffmpeg -i input.mp4 -vf "scdet=t=10,select=gt(scene\,0.1)" -vsync vfr scene_%04d.png

Note: The scene metadata read by select is the scdet score normalized to 0–1. gt(scene\,0.1) selects frames whose score exceeds 10%.

Print Timestamps via showinfo

ffmpeg -i input.mp4 -vf "scdet=t=10,metadata=print:key=lavfi.scd.score" -f null /dev/null

Threshold Suggestions by Content Type

Use case	Recommended threshold
Film cut detection	8–15
Sports footage	15–25
Animation	10–20
Surveillance footage	5–10
Slideshow-style videos	30–50

Caveats

Fades and Dissolves Are Hard to Detect

Hard cuts (instant transitions) are detected reliably, but fades and dissolves (gradual transitions) can trip up scdet and cause misdetection.

Long Videos Take Time

Scene detection decodes every frame, so long videos take a while to analyze. You can narrow the analysis with -ss and -to.

Frequently Asked Questions

What threshold should I use for scene detection?

gt(scene,0.4) flags significant cuts. Lower to 0.3 for fast-cut content, raise to 0.5 to catch only hard cuts and ignore camera moves.

How do I export the timestamps to a file?

ffmpeg -i in.mp4 -filter:v "select='gt(scene,0.4)',showinfo" -f null - 2> scenes.log then grep for pts_time.

Why does scene detect miss obvious cuts?

Cross-fades and flash-cuts can hide under the threshold. Combine scene detection with blackdetect to catch fade-outs that act as cuts.

Can I split the video at every detected scene automatically?

Yes — feed the timestamps into a wrapper script that calls ffmpeg -ss A -to B -c copy partN.mp4 per detected range.

Does scene detect work on animation?

Yes but tune the threshold. Animation has flatter colour distributions, so lower the threshold to 0.25–0.3 to catch real cuts.

Tested with ffmpeg 6.1 / Ubuntu 24.04 (GitHub Actions runner) Primary sources: ffmpeg.org/ffmpeg-filters.html#scdet / ffmpeg.org/ffmpeg-filters.html#select