Change a video's frame rate (fps)
Going from 60 to 30 frames per second (fps) makes the file lighter; going from 25 to 30 makes it comply with a platform's requirements; interpolation can even smooth out a choppy video. ffmpeg changes the frame rate without changing the length.
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To lower the frame rate, the simple method is enough. To raise it, interpolation creates in-between frames, but it is very slow.
The lower the number, the better the image and the bigger the file.
How to use it
- Install ffmpeg if you haven't already.
- Open a terminal in the folder containing your file.
- Copy the generated command, adjust the file names if needed, then run it.
- Open the resulting file to check the result.
Lowering the frame rate to save space
Going from 60 to 30 fps reduces the file size by about 30 to 40%, with no visible difference for most content. It's a good first step before heavier compression.
Raising the frame rate
Doubling the number of frames by duplication doesn't make the video smoother. Only interpolation invents in-between frames. It's computationally heavy: expect it to take several times the length of the video.
Frequently asked questions
Why doesn't the length change?
The fps filter keeps the video's length and adjusts the number of frames. To slow down or speed up a video, use the dedicated speed page instead.
Does interpolation give good results?
On a calm video (landscape, interview), the result is often convincing. On a fast or high-contrast scene, it creates artifacts, such as distortions around moving objects. Try it on a short clip first.
Which frame rate should I choose for WhatsApp or YouTube?
30 fps works well for both. Save 60 for content where smoothness matters (gaming, sports): the file is nearly twice as big.
Do I need to adjust the audio too?
No: the audio is copied unchanged, so its sync stays intact.