Dedicated processing
A background Worker keeps intensive media work away from the interface.
Video + audio, merged to MP4.
Runs entirely in your browser. Your files are never uploaded, and the finished MP4 stays yours.
Video source
VIDEO_IN00:00:00
Audio source
AUDIO_IN00:00:00
Export settings
Choose the container, quality, resolution, and how tracks with different durations should end.
Choose a video and an audio file to start.
- 1
Load sources
Read the selected video and audio.
- 2
Inspect tracks
Verify timing, codecs, and stream data.
- 3
Merge & encode
Create a compatible local MP4.
- 4
Save output
Download the completed file to your device.
Why VDA Media Lab
A focused media utility, built for privacy.
Streamed local storage
Temporary output is written to OPFS instead of occupying your tab's memory.
Your files stay yours
No upload queue, account requirement, or server-side copy of your media.
Control the export
Choose the output format, quality, resolution, and how tracks with different durations should end.
Align tracks your way
Adjust audio delay and decide whether the finished video follows the shorter track, video, or audio.
Ready in your browser
Use the tool directly in modern browsers with WebCodecs support—no desktop app or account required.
Common questions
Before you merge
The details that matter before your first export.
No. The selected media is handled inside your browser. VDA does not send it to our servers.