How to add a voiceover to a video online

Repair one missing explanation first

Imagine a drawer assembly video that clearly shows the screw being tightened but never says when to stop. Keep that useful picture and write one sentence: “Tighten until the bracket stays still, then check that the drawer moves freely.” Confirm the instruction against the actual assembly guidance before recording it. The voiceover should explain the visible step rather than cover a missing or misleading demonstration.

Prepare a quiet microphone take

Finish the rough picture order before recording so later cuts do not move the action away from your words. Plug in headphones to avoid recording sound coming from the computer’s speakers. Check the browser’s microphone selection and permission. Read the sentence aloud once and listen to a short test for distortion, room noise, and an audible beginning and ending.

Record at the timeline cursor

Open the web editor’s Audio tab and place the cursor just before the bracket step. Choose Record narration and read while the preview plays. Stop when the sentence is complete; the web flow saves an added narration clip automatically at the position where recording began.

Listen to it on the timeline. If the take is wrong, remove or undo that clip and record again. This web flow does not require a separate acceptance screen. Keep sentences short enough that repeating one take does not mean repeating the whole demonstration.

Align the explanation and balance the sound

Move or trim the narration so “check that the drawer moves freely” coincides with the movement being shown. Leave room for the viewer to inspect the result. Listen for two voices speaking at once. Lower or mute the relevant original clip when necessary, then check that useful mechanical sound still supports the explanation. The new microphone take does not automatically silence all existing project audio.

Review the downloaded result

Play a passage before the narration, the narrated action, and the transition afterward. Check headphones and the device’s speakers at a comfortable volume. Export a short MP4 test and listen outside the editor to confirm the timing. If the source already contains clear speech, compare whether the added explanation helps or merely repeats it. Save the editable project as well as the finished video for later corrections.