video

Reverse Clip

Reverse a section of video or create a forward-and-back MP4, with optional reversed audio and no media upload.

Local processing

About your filesFiles and content selected in this tool are processed in your browser and are not uploaded to a Browser Kitty backend.

Operation demo See the basic workflow in a short video.

About this tool

Reverse Clip lets you select start and end times in a video, then export that segment in reverse or as a forward-and-back ping-pong MP4. Review the result, choose a filename and save it to your device.

Output is H.264 MP4 at 15fps, silent by default. If the source audio can be read, optional reversed AAC is available. Browser Kitty serves the multi-thread FFmpeg WASM build; the selected video stays in the browser.

Good for

Reverse a short moment from a recorded video
Make a forward-and-back looping-style ping-pong clip
Reverse the original audio when supported
Create MP4 clips without uploading private videos

What it can do

Key capabilities available in this tool.

Convert a selected range into a reversed H.264 MP4
Create a forward-and-back (ping-pong) MP4
Reverse supported AAC audio, or keep the default silent output
Preview the finished MP4 and save it under your chosen filename

How to use

Open the tool, select a compatible H.264 MP4 and preview the source.
Choose the section with the timeline or the start/end time inputs.
Select Reverse or Ping-pong, then choose quality and optional audio.
Create the MP4 and review the generated result.
Enter a filename and select Save MP4.

Supported

Output: H.264 MP4 at 15fps, with Reverse and Ping-pong modes.
Audio: Silent by default; compatible source tracks can be reversed into AAC. Selecting among multiple audio tracks is unsupported.
Selection: 0.5 to 10 seconds; the experimental 1080p-class option is capped at 5 seconds. Long-edge 360/720px is the initial practical scope.
Result: MP4 preview, editable filename, download, cancellation and retry.
Runtime: Browser Kitty uses the MT edition with cross-origin isolation scoped to this app URL.

Limitations and notes

The initial tested scope is H.264 MP4 in Windows Chrome and Android Chrome. Other devices and formats are not guaranteed.
Output is always 15fps, and the input frame rate is not preserved. Selection points may be adjusted slightly to frame boundaries.
Long sections and high-quality exports can be slow or fail due to device memory. The 720p-/1080p-class high-quality options remain experimental.
HEVC/H.265, HDR/10-bit color fidelity, iPhone Safari and multiple-source-audio-track selection are not supported claims.
The MT build requires secure hosting, cross-origin isolation and SharedArrayBuffer. For direct file opening, use the upstream ST HTML.

Frequently asked questions

Is my video uploaded?

No. The web page itself is downloaded, but your source video and generated MP4 are processed locally and are not uploaded to Browser Kitty.

Can I make a forward-and-back video?

Yes. Choose Ping-pong to join a forward section with its reverse in a single MP4.

Can I reverse the sound too?

You can enable reversed audio when a supported source track is detected. The default output is silent.

Can I open the HTML offline?

This Browser Kitty edition is multi-thread and needs cross-origin isolated hosting. Use the upstream single-thread HTML for direct offline file opening.

Offline version and source code

Browser Kitty serves the MT edition, which requires secure hosting, COOP/COEP isolation and SharedArrayBuffer. FFmpeg/WASM and Workers are embedded without runtime downloads or media uploads. For direct offline file use, download the ST edition from the [Reverse Clip v1.0.0 Release](https://github.com/ttomohisa/htmlapps-reverse-clip/releases/tag/v1.0.0).

View source on GitHub