YouTube Sound On Video
Paste a YouTube link, pick your video, press Combine. It all happens in your browser: nothing is uploaded anywhere.
1Your video
2The sound
Recording…
How it works: the video plays here and this page records what you hear, for as long as your video runs. When the browser asks what to share, pick this tab and tick Share tab audio. Works in Chrome and Edge on a computer. If an ad plays first, let it finish and press Record again.
3Combine
More options
Pick a video and a sound first.