Three browser video tools for the jobs that don't deserve a video editor install

Most of the video work I actually do is small: trim three clips into one with a caption, turn a screen recording into something a colleague's laptop will play, or fix an MP4 that refuses to start playing on a web page until it has fully downloaded. None of that should need a desktop editor or an upload to someone's server. Omikuji Tools has one page for each, and all three process the file inside your browser.

Local Video Editor: clips, captions, background music

Load videos (MP4, WebM, MOV) and audio (MP3, WAV, M4A), cut the segments you want, and line them up on a timeline — drag to reorder, click a clip to change its volume or mute it. Captions are placed at the playhead with their own start and end time, position, size and colour. Audio files go on a BGM lane with a volume control.

Output is fixed at Full HD: 1920×1080 landscape or 1080×1920 portrait, at 24, 30 or 60 fps. Sources are scaled to fit with black letterboxing, so you can mix 4K footage with phone clips. The one thing to know up front, which the page states plainly: export is a real-time recording at 1× speed. A one-minute video takes about a minute, and the tab has to stay open.

Your edits autosave in the browser, and you can save the project as project_data.json. The JSON holds the in/out points, captions and BGM placement, but deliberately not the video files; when you reopen it, you re-pick each file and the edit comes back.

Video Converter & Compressor

This one takes any video your browser can play — typically WebM, MOV and MP4 — and writes MP4 (H.264), WebM (VP9) or an animated GIF. To make a file smaller, cap the long side at 1080p, 720p or 480p and pick a quality of High, Standard or Compact; it never upscales. Drop several files at once and each shows its before/after size.

Two limits worth knowing. It uses the browser's WebCodecs encoder, so it needs a recent Chrome, Edge or Safari. And formats the browser cannot play, such as AVI or MKV, cannot be used as input. GIFs have no audio, and their frame rate follows the quality setting (15, 10 or 6 fps).

MP4 Fast Start Converter

The quiet bug behind "the video on my page only plays after a long wait": the MP4's moov atom, the index that tells the player where everything is, sits at the end of the file, so the browser has to download the whole thing before it can start. This page moves moov to the front and rewrites the stco / co64 chunk offsets to match — the same result as qt-faststart, for machines where you cannot run ffmpeg.

There is no re-encoding, so quality is unchanged. It accepts .mp4, .mov and .m4v, handles several files at once, and tells you when a file is already Fast Start so you don't process it for nothing.

👉 Local Video Editor — clip, caption and add BGM, export MP4. 👉 Video Converter & Compressor — WebM/MOV to MP4, WebM or GIF, and smaller. 👉 MP4 Fast Start Converter — make an MP4 start playing before it finishes downloading.

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