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Add music or narration, place it on the timeline, balance the mix, and export.
A video often needs sound it was not recorded with: music under a montage, narration over a screen capture, an ambience bed under B-roll. This tool lays a new audio file onto the timeline alongside whatever is already there, lets you position it in time, balances the two, and exports one video with the combined mix.
Adding keeps the original soundtrack and mixes the new audio with it — that is what you want for music under speech, or a voiceover on top of location sound. Replacing discards the original entirely, which is right for a silent montage with a music track or for footage whose sound is unusable. If you find yourself pulling the original down to nothing to make the new track audible, replacing is the cleaner operation and produces a simpler file.
Music rarely starts where you want it to. Offsetting the new audio lets you land a beat on a cut, start a track after an intro, or place narration against the section it describes. When the music is longer than the video, decide how it ends: a hard stop at the last frame always sounds like a mistake, so fade the tail out with the audio fade tool. When it is shorter, either loop it or let it finish before the picture does — silence at the end is far less jarring than a truncated phrase.
Speech has to stay intelligible, and music competes with it directly. As a starting point, sit music somewhere around 15 to 20 dB below dialogue and adjust by ear on the quietest words rather than the loudest. Check the result on phone speakers as well as headphones: small speakers have almost no bass, so a mix that sounds balanced on good headphones can leave speech buried under a track that seemed subtle. If you want the music to move out of the way automatically during speech, the ducking tool does that.
Yes — the new track is mixed with it, and you set the balance. If you want the original gone entirely, use the replace-audio tool instead.
Roughly 15–20 dB below the dialogue as a starting point, then adjust by ear against the quietest words. Check the mix on phone speakers, not only headphones.
A longer track can be trimmed and faded out at the end; a shorter one can be looped or simply allowed to finish early. A hard cut at the last frame always sounds like an error.
Yes. Offset the track on the timeline so it begins where you want — after an intro, on a specific cut, or against the section it belongs to.
Common formats including MP3, WAV, M4A and OGG work, since decoding is handled by your browser’s own audio support.
