Make a quiet video louder, or softer, and keep every frame of the picture as it was
Processed in your browser. Nothing is uploaded. Updated on 24 Oct 2026.A phone clip recorded across a room, or a screen recording with a quiet microphone, often needs only its sound raised. Drop the video, leave the audio slot empty and set Original sound anywhere from 0 to 200%. Only the sound is encoded again, as AAC; every video frame is copied untouched. Above 100%, parts that were already loud can distort, so listen to the saved file before you share it. Nothing is uploaded.
Press Choose video and pick an MP4, MOV or M4V file; leave the audio slot empty.
Original sound starts at 150%; drag it up to 200% for a very quiet clip, or below 100% to make it softer.
Press Save the video and play the saved file to check it. The picture is copied and only the sound is encoded again.
This page puts a new sound track on a video: a song, a voice-over, a cleaner microphone recording, or nothing at all. It was built for the job of finishing AI-generated clips for YouTube, where the picture is final and only the sound changes, and for that job the one thing that must not happen is the picture getting worse.
So the picture is never re-encoded. Every video frame is read from your file and written into the new one byte for byte, which is why a 4K or 8K video keeps every pixel and why a long file finishes quickly: nothing is decoded, nothing is compressed a second time. The quality check behind this page compares the frames of the result with the frames of the original and requires them to be identical.
Longer or shorter than the video. Audio that runs past the end of the video is cut at its last frame. Audio that ends early leaves silence, or starts again from the top if you choose Repeat. A fade in and a fade out are there for music.
The rest of the article, and all 6 questions about Add Audio to Video, are on the Add Audio to Video page.
Drop the video and the music file here and save. The video frames are copied into the new file exactly as they were, not re-encoded, so a 1080p or 4K video keeps every pixel. Only the sound track is new.
Drop the video and the new audio, leave "Original sound" at 0%, and save. The old sound track is dropped and the new one takes its place, lined up where you put it and cut at the video's last frame if it is longer.
Yes. Set Original sound above 0% and the video's own sound stays, with the new audio mixed in at its own volume. For background music under speech, 100% original and 20 to 30% music is a common starting point; a fade-out at the end avoids stopping mid-note.
MP3, M4A, AAC, WAV, OGG, Opus and FLAC, and the sound of another MP4 or MOV. The video must be MP4, MOV or M4V. The result is always an MP4 that plays everywhere and uploads to YouTube as it is.
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Same job, other tools: Change Video Speed – Speed up a video or make slow motion, from 0.25x to 4x, with the sound kept in pitch · Compress Video – Make a video file smaller at a lower bitrate or resolution, right in your browser · GIF to MP4 Converter – Turn an animated GIF into a much smaller MP4 video, each frame kept for its own delay · Video to GIF – Cut up to 15 seconds out of a video and save it as a looping animated GIF · Video to Animated WebP – Turn up to 15 seconds of a video into a full-colour animated WebP, made in your browser.
On the related tools: Combine AI Video Clips – Join Google Flow, Veo or other AI clips into one video in story order.