OneTaskBy Tim King · Updated
Frame by Frame Viewer
Step Through a Video One Frame at a Time
OneTask is free, with no sign-up, and built by one person.
If this tool saved you time, a coffee helps keep new ones coming.
How the Frame by Frame Viewer works
This frame by frame viewer lets you step through a video one frame at a time, forwards or backwards, and see exactly which frame you are on. Use the buttons or the arrow keys, then save the frame you need as a full-size PNG. The video is played in your browser and never uploaded.
Normal players jump in whole seconds or skip to the nearest keyframe, which can be 50 or more frames apart. That is fine for watching, but useless for checking a finish line, a ball crossing a line, a lip-sync error or the exact frame to cut on. Stepping single frames shows what actually happened.
How the frame by frame viewer works
Browsers do not report the frame rate of a video, so you choose it. The tool works out the current frame number from the playhead, adds or subtracts the step, and seeks to the middle of the new frame. Seeking to the middle rather than the edge stops rounding errors from landing on the frame before.
| Frame rate | Frame length | Common source |
|---|---|---|
| 23.976 / 24 | 41.7 ms | Film, streaming drama |
| 25 | 40 ms | PAL TV, European video |
| 29.97 / 30 | 33.4 ms | US TV, most phones and webcams |
| 50 | 20 ms | PAL sport, action cameras |
| 59.94 / 60 | 16.7 ms | Gaming capture, phone slow modes |
If you do not know the rate, step forward 10 frames from a moving shot. If the picture sometimes does not change on a step, the rate you chose is higher than the file's; if it jumps unevenly, it is lower. The frame rate detector can measure it for you.
Keyboard shortcuts
- Right arrow or . steps forward one frame.
- Left arrow or , steps back one frame.
- Hold Shift to step 10 frames.
The shortcuts work whenever the page has focus and you are not typing in a box.
Tips and pitfalls
Variable frame rate phone video. Phones often record at a frame rate that drifts with the light. Stepping still works, but frame numbers are estimates and can be one or two out over a long clip.
Stepping backwards is slower. Decoding a frame usually means starting from the previous keyframe, so stepping back in a long-GOP file can take a moment. Wait for the time to update before stepping again.
Saved frames are full size. Save frame captures the decoded frame at the video's own resolution, not the size shown on screen.
How to read the result
The stats show the playhead time, the frame number out of the total, the length of one frame at the chosen rate and the video's pixel size.
FAQ
How do I watch a video frame by frame?
Load the video, choose its frame rate, and press Forward 1 or the right arrow key. Each press moves exactly one frame. Back 1 or the left arrow goes back one, and the 10-frame buttons skip faster through longer passages.
Why do I need to choose the frame rate?
Browsers play video but do not tell web pages its frame rate. The tool uses your choice to work out how far one frame is. Most phone and webcam video is 30, film is 24 and European TV is 25 frames per second.
Can I save a single frame as an image?
Yes. Step to the frame you want and press Save frame, then Download. You get a lossless PNG at the video's full resolution, named with the frame number so a series of saved frames stays in order.
Is my video uploaded to step through it?
No. The video is opened and decoded by your own browser, and saved frames are created on your device. Nothing is sent to a server, so private and unreleased footage stays with you.
See also: all Video & Screen tools, Images, Audio, PDF, SVG, Simulations & Screensavers, Generative Art, Chart Makers, 3D Model Viewers, Drawing Pads, Mockups & 3D Making, Diagram Makers, 3D Science, Tracker Music.
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