Media Tools
Video Merger
Join multiple video clips into a single movie instantly.
Runs in your browser Your input never leaves your device.
About this tool
Choose two videos and the tool plays File 1 followed by File 2 in one MP4, using ffmpeg's concat filter in WebAssembly. It runs in your browser and nothing is uploaded. The clips are re-encoded, so it is lossy and slow for long videos. The concat filter expects both clips to have the same resolution and both to contain an audio track; otherwise it fails. Only two clips can be joined per run. The first run downloads the ffmpeg engine (about 25 MB) from a CDN, which can take from a few seconds to a minute on a slow connection; later runs on the same page reuse it.
How to use it
- Choose File 1, the clip that plays first.
- Choose File 2, the clip that follows.
- Press Process and wait for the progress bar.
- Preview and press Download (output.mp4).
Common problems
- Processing failed
- The clips likely differ in resolution or one has no audio. Make them the same size first, for example by converting with the same settings, and make sure both have sound.
- I need to join more than two clips
- Merge two, then merge that result with the next clip.
- It is slow, or the tab freezes or runs out of memory
- ffmpeg runs in a single browser thread on your device. Use a shorter or smaller file and close other heavy tabs.