How to edit videos and enhance audio completely offline in your browser
Most quick edits are small: cut the dead air at the start, crop a landscape clip for a vertical feed, brighten a dark room and put your name in the corner. Uploading a large file to a server for that is slow, and for private footage it is unnecessary. Modern browsers can decode, preview and re-encode media locally.
Preview first, render once
The Video Editor draws every frame onto a canvas with your current settings applied. Brightness, contrast, saturation, black and white, rotation, flips, fades and text appear while the clip plays, so you decide by watching rather than by rendering test files.
The timeline has two handles for the in and out points and a separate playhead. Use Set in and Set out at the current position, step one frame with the −1f / +1f buttons, and keep Loop on to replay only the selected range.
Reframe for the platform
Pick an aspect ratio before you add text, because the crop decides where corners are:
- 16:9 for YouTube and desktop players
- 9:16 for Reels, Shorts and TikTok
- 1:1 for square feeds
- 4:3 for slides and older footage
The crop is centred. A landscape clip cropped to 9:16 keeps the middle third, so subjects at the edge may need a rotation or a different source.
Audio that sits under the picture
Video volume, mute and audio fades work on the original track. Add a background music file to mix it under the dialogue, or switch on Replace original audio for a music-only edit. The music is trimmed to the output length automatically.
Two ways to export
Fast export records the live canvas and original sound with the browser's MediaRecorder. It starts instantly and needs no extra download, but runs in real time and supports the formats your browser can record.
HQ export runs FFmpeg compiled to WebAssembly. The first run downloads about 32 MB, which the browser then caches. It adds background music, volume boost beyond 100%, animated GIF output, CRF quality control and exact frame rates. You can read the generated command:
ffmpeg -ss 00:00:03.00 -to 00:00:18.00 -i "input.mp4"
-filter_complex "[0:v]crop=...,eq=brightness=0.08[v0]" -map "[v0]" ...Cleaning up a voice recording
Laptop and phone microphones pick up desk rumble and sound muffled. The Audio Converter & Enhancer fixes the common problems in one pass:
- Voice clarity removes rumble below 80 Hz and lifts speech presence around 3 kHz.
- Bass and treble add warmth or crispness in ±12 dB steps.
- Normalise loudness targets −16 LUFS with a −1.5 dB true-peak ceiling, a common level for podcasts and web video.
- Speed and pitch change tempo without chipmunk voices, or shift pitch in semitones.
Use the Original / Enhanced switch while previewing to compare. Small changes usually sound better than large ones.
Tags travel with the file
MP3 files often carry ID3 tags: title, artist, album, year, genre and track number. The enhancer reads existing tags and lets you edit them before export, so a podcast episode or demo track shows the right name in players.
Related tools
Cut a single section with the Audio Trimmer, join parts with the Audio Merger, make a quick cut with the Video Trimmer, or capture footage with the Screen Recorder.
Limits
Everything runs in your device's memory. Very long or 4K files can be slow on phones; trim first or lower the output height. The preview approximates FFmpeg's colour filters closely but not to the exact pixel, and loudness normalisation is only applied on export.