How to Reverse a Video and Its Audio, Then Save an MP4

1. Understand reverse versus ping-pong video

Reverse mode plays the selected section backward, from its final frame toward its first. For example, an object thrown away may appear to return to the thrower's hand.

Ping-pong mode plays the same section forward and then backward. Reverse Clip joins both directions into one MP4 and avoids duplicating the frame at the turnaround. This differs from a player's loop toggle: the forward-and-back motion is actually encoded into the exported file.

You do not have to process the whole source video. Set the start and end points to work with just the few seconds you need.

2. Prepare a compatible MP4 clip

Open Reverse Clip, select a source file and preview it. Start with an H.264-encoded MP4. The app's main tested scope is H.264 MP4 on Windows Chrome and Android Chrome; formats such as HEVC/H.265 are not guaranteed to work.

Reversing video involves re-encoding, so begin with a short selection of roughly 0.5–5 seconds. Up to 10 seconds is experimental, and the 1080p-class option is limited to 5 seconds. Even if the source video is much longer, the intended workflow is to choose only a few seconds.

iPhone Safari is outside the guaranteed support scope. On mobile, prefer an environment the project has actually tested, such as Android Chrome. An MP4 extension alone does not guarantee that the internal codec is supported.

3. Set the start and end time of the section

In the Edit view, use the timeline or enter numeric start and end times in seconds. For an action occurring in the middle of a longer recording, select only the moments immediately before and after it.

The selected range must be at least 0.5 seconds. A short section that clearly shows the action is generally easier to process and less memory-intensive than a long one.

The export may adjust a requested time slightly to match frame boundaries. Do not assume that the cut points will match the source at exactly the same frame.

4. Choose Reverse or Ping-pong and an output size

Choose Reverse or Ping-pong. Reverse makes the selected sequence run backward. Ping-pong joins the forward and backward parts, producing a longer output than a single pass; check the resulting duration before sharing it.

Next, choose the output size. Long-edge 360px or 720px are the initially practical options. Some higher-quality choices are experimental, and longer or larger exports may exceed device memory or fail.

The result is encoded as H.264 MP4 at 15fps. The tool does not preserve a 30fps or 60fps source frame rate. It also does not perform lossless stream copying: reordering the video frames requires new encoding.

5. Decide whether to reverse the sound

Silent output is the default. If the app can read a compatible source audio track, you can choose to include reversed sound. The option may not be available when the video has no audio or uses unsupported audio encoding.

In Reverse mode, the selected sound is reversed together with the video. In Ping-pong mode, forward audio is followed by backward audio at the turnaround. Exported audio is AAC; original codec, fidelity and track layout are not preserved exactly.

Speech and music become difficult to understand when played backward. Leave the output silent if the visual effect is your goal. The tool does not let you choose a specific track from multiple source audio tracks.

6. Generate the MP4 and review the result

Review your choices and create the MP4. Rebuilding a video's frames in reverse may take noticeably longer than copying a file, even for a short clip. Processing time varies with section duration, output size and device capabilities.

You can cancel a running export. If conversion fails or the generated file is incomplete, the app does not make it available as a completed MP4. Shorten the range or lower the output size before trying again.

When generation succeeds, preview the result. Check that the movement runs backward as intended, the ping-pong turnaround looks right, and reversed audio plays if you enabled it.

7. Save the reversed video as an MP4 file

Enter a filename for the completed clip and press Save MP4. The download contains a newly encoded section; it does not edit or overwrite the source file in place.

A browser indicating that a download has started is not proof that saving finished successfully. Check your downloads folder and, if necessary, play the result in another video player.

If you switch to a different source video while an unsaved result exists, the app asks you to confirm discarding it. Save anything you want to keep first.

8. Fix common input, audio and export problems

If your file cannot be opened, test with a short H.264 MP4. MP4 is a container; videos encoded with HEVC/H.265 are outside the guaranteed input scope. HDR and 10-bit color fidelity are also not guaranteed.

If processing is slow or fails, reduce the section to about 0.5–5 seconds and try a smaller long-edge setting such as 360px. The 720p- and 1080p-class high-quality options remain experimental.

When reversed sound cannot be enabled, check that the source contains a supported audio track. You cannot choose among multiple tracks. Also check whether Silent, the default option, was left selected accidentally.

Browsers outside the tested scope, including iPhone Safari, may not work as expected. The Browser Kitty edition runs multi-threaded and requires browser support for SharedArrayBuffer plus the appropriate isolation settings.

9. Privacy, offline use and important limitations

Reverse Clip reads, reverses and exports the selected video inside your browser. It does not upload the media to a conversion server. Downloading the web page when you open it is separate from uploading the source video.

The multi-thread edition served by Browser Kitty requires secure hosting and cross-origin isolation. If you want to save an HTML file and open it directly via file://, use the single-thread build distributed with the upstream v1.0.0 Release.

The export is H.264 MP4 at 15fps. The tool is not intended to retain the original frame rate, pristine source quality, HDR color accuracy or multiple audio tracks. If you only need to cut out a section without quality loss, consider a separate lossless video cutter rather than a reverse-video export.

Tips and limitations

• Start with an H.264 MP4 section around three seconds long, silent output and a small export size; then adjust the range and audio options.
• A ping-pong video contains both forward and backward motion, so expect it to be longer than a single pass.
• If your source audio is unsupported, you can export a silent reversed MP4 and add a different sound later in an editor.
• Select only the motion you want to reverse instead of processing unnecessary footage.