Why Do This in Your Browser?
Reversing video — playing it backward — is a classic creative effect. Magic tricks, comic surprise moments, satisfying time-rewind shots: all of them depend on a clean reverse. Until recently, this meant a desktop editor and a few minutes of menu hunting; online tools either capped length, watermarked output, or uploaded your video.
This tool reverses video and (optionally) audio in browser. The FFmpeg `reverse` filter buffers the entire decoded video in memory, then writes frames out in reverse order; the `areverse` filter does the same for audio. Output is a clean MP4 — no watermark, no upload, no signup.
How It Works
Reversing video isn't a streaming operation — every frame has to be decoded and held in memory before writing them in reverse. That puts a practical cap on length: longer videos need more RAM. In a browser that limit arrives fast: in our tests a single-pass reverse of 1080p ran out of memory somewhere between 20 and 60 seconds. So this tool cuts longer clips into pieces that fit (about 6 seconds each at 1080p30, longer at lower resolutions), reverses each piece and joins them in reverse order. A 60-second 1080p test clip came out with all 1,800 frames in exact reverse order, including at the joins.
Audio options matter for the final effect. Reversed audio produces the iconic 'backward' sound (often used for surreal or supernatural effects). Muted audio is more practical for sight-gag reversal where the soundtrack would be distracting. Forward audio over reversed video creates an uncanny mismatch sometimes used in music videos.
Tip: Reverse a specific segment by trimming it first, then reversing the trimmed clip. Pair reverse with the Speed Changer for slow-motion rewind effects.
Common Use Cases
Worked example: why a 60-second clip is reversed in pieces
FFmpeg's reverse filters keep every decoded frame in memory before writing any of them out (the FFmpeg documentation warns that the filter "requires memory to buffer the entire clip"). A decoded 4:2:0 frame takes width × height × 1.5 bytes, so one second of 1080p at 30 fps is about 89 MiB. This tool gives each piece a budget of 600 MiB and sizes pieces from the clip's own resolution and frame rate:
| Source | Decoded size per second | Piece length | Pieces for a 60 s clip |
|---|---|---|---|
| 4K (3840×2160), 30 fps | 356 MiB | 1.6 s | 38 |
| 1080p (1920×1080), 30 fps | 89 MiB | 6.7 s | 9 |
| 1080p, 60 fps | 178 MiB | 3.3 s | 19 |
| 720p (1280×720), 30 fps | 40 MiB | 15.1 s | 4 |
Each piece is reversed on its own and the pieces are joined in reverse order, so the last piece of the original plays first. In our 60-second 1080p test every one of the 1,800 frames came out in exact reverse order, joins included. Reversed audio uses the same piece boundaries.
Sources, checked October 11, 2026: FFmpeg filters documentation, reverse and areverse; piece budget and formula from this tool's source code.