Add Audio to Video in Your Browser

A video can be complete visually and still feel unfinished. You may have a silent animation, a screen recording whose clicks are distracting, or a short phone clip that needs music underneath a voice. Start with the video you want to keep and an audio file you have the right to use. The tool combines those files into a fresh download; it does not generate a new scene or alter the images in your existing clip.

Think about the audience before you choose a track. A fast montage can carry a more prominent rhythm, but a demonstration with spoken instructions needs space for the voice. Music that sounds exciting on its own may not serve the pictures once both are playing.

Keep the source files until you have watched the new download. The export is a separate result, which gives you room to try another track or change the balance without losing the original recording.

Choose a video file first, then choose the audio you want to hear with it. If the clip already contains sound, decide whether to keep that sound and mix it with the new track or replace it entirely. Move the volume controls to set the intended balance. A narrated tutorial often benefits from lower music, while a silent montage may call for a stronger soundtrack. The player initially shows your original video, not the new mix. Press the export button to create the result, then play it and adjust the settings for another export if needed.

You can choose where the new sound begins in the video and skip an unwanted introduction in the audio file. If the selected passage ends before the video does, turn on Repeat to fill the remaining time, or turn it off to play that passage only once. A long passage stops with the video. Use the fade controls to ease the music in and out, then listen near each loop join: ambient music often repeats more naturally than a song with a sharp ending. Adjust the settings and export again if needed; your original files remain unchanged.

Mix is for footage whose original audio matters. It lets you keep speech, ambience, or the sound of an action while adding another track underneath. Use the separate levels to keep the main sound intelligible; there is no universally correct percentage because recordings vary widely. After exporting, play a section where the speaker is quiet and another where the music is loud. If important words disappear, turn the added audio down and export again.

Replace is simpler: the existing sound is removed from the output and the selected audio becomes the soundtrack. Choose it for silent clips, unwanted camera noise, or footage whose original audio should not be heard. Replacing audio is not the same as muting the preview player: the new exported file uses the chosen track. If you change your mind later, return to the source video and make another version using Mix. The original file on your device is not modified.

A silent source does not need to be mixed with an imaginary original track. When there is no existing sound, the added audio carries the result by itself. If the video does include a quiet but useful background, compare both modes before deciding to remove it.

Volume controls change the balance of the exported audio rather than the loudness setting on your speakers. Set your listening device to a comfortable level first, then use the tool's sliders to adjust the relationship between the two recordings.

The export aims to copy the video stream rather than decode and encode every image again. Copying the stream avoids an additional generation of picture compression, so supported combinations retain the source frames, dimensions, and frame rate. Audio needs to be prepared for the new file, particularly when two tracks are mixed. The exact result also depends on whether the selected video stream can be placed in the output container.

This is not a tool for improving resolution, changing frame rate, adding visual effects, or converting an unsupported picture format. It will not secretly transcode a video to force an export through. If your input cannot be copied to a compatible output, you will see an error and can try another source file. That is a deliberate trade-off: the straightforward workflow protects the picture you supplied instead of making an unannounced quality decision for you.

A file extension alone is not a reliable description of the video codec inside. Two MP4 files from different apps may behave differently. If one fails, check how it was exported rather than simply renaming it; renaming does not alter the encoded picture.

Keeping the frame data intact does not guarantee that every player treats every container in exactly the same way. Test the downloaded file wherever you intend to show it, especially if you are sending it to another person for review.

The actual video and audio files are processed in your browser. They are not uploaded to this site's media server for mixing. The tool may need to load its processing code when you open or use it, so an internet connection can be needed to start even though the media operation itself is local. If you are working with private material, you can still review your browser's permissions and use a trusted device before selecting the files.

Local processing is also why performance differs across devices. A laptop with available memory may handle a clip that makes a phone tab struggle. This version accepts videos up to 150 MB and three minutes long, and audio files up to 30 MB. These are safeguards rather than a guarantee that every file under the limits will succeed. Close memory-heavy tabs, use a shorter clip, or switch to a desktop browser if a large job runs out of memory.

Do not close the tab while it is preparing the download. If the browser reloads or the device sleeps, you may need to select the files again. Keep the source copies in a safe place until the new file has opened successfully.

Working in a browser does not remove ordinary device-security considerations. On a shared computer, be mindful of the downloads folder and any browser extensions you have installed. Choose a device you trust when handling material you would not want others to see.

For a picture-preserving export, use H.264 or HEVC video in MP4 or MOV, or VP8 or VP9 video in WebM. The output keeps the video's container: MP4 remains MP4, MOV remains MOV, and WebM remains WebM. A browser may not preview every supported source codec, even when the tool can copy its picture stream. Common audio files can be selected, but whether a recording can be decoded depends on its actual encoding, not just its filename. If the audio cannot be processed, try a conventional export from the app that made it.

Preview playback and final export are related but separate. The preview depends on codecs your browser can play directly, whereas the processing engine handles the export. A browser that cannot display a particular source may still be able to process it, and a playable file may fail if its picture stream is not suitable for direct copying. Check the downloaded result in your usual player before deleting any source material. Keeping your originals is always the safest way to revise an edit.

If an audio file is rejected, export it again from the app that created it. Choose a common codec rather than changing the filename extension. The underlying recording needs to be readable; its label alone cannot make an incompatible encoding work.

If a source previews but cannot be exported, this is not necessarily a browser playback problem. Export with unchanged picture frames imposes stricter container requirements. The error is a cue to choose another source or prepare the video elsewhere, not a reason to expect the tool to convert it silently.

You can use your own recording, a track you composed, or music licensed for the way you intend to share the video. The ability to add a sound does not grant permission to publish it. A track that is fine for private listening may have different conditions for a public post, a client deliverable, or an advertisement. Check the license and any attribution requirements before you publish, and keep a record of the permission that applies to your project.

Sound choice also affects the edit itself. A voiceover should be clear enough to follow on a phone speaker. Background music should support the pace of the visuals without masking dialogue. Listen on more than one device if the result is important: a mix that seems balanced through headphones can be too heavy through small speakers. If the clip will be viewed without sound, consider captions in a separate editing step; adding music cannot convey spoken information to someone watching muted.

Keep the license information with your project files. If a platform or client later asks about the track, the terms that applied to your use will be easier to find. Seeing a song in another public video is not evidence that you can use it in yours.

Consider the sound's character as well as its rights. A song with prominent vocals can compete with narration, while a simple instrumental may leave more room for the message. There is no automatic selection here; you can audition different files and decide what fits.

This page is for one video and one added audio file at a time. It does not have a multitrack timeline, automatic beat matching, noise cleanup, or a library of songs. Keeping the task narrow makes it easier to finish a short social clip, a product demonstration, or a presentation excerpt when all you need is the right soundtrack. To make another version, download the first output, reset the tool, and select the next pair of files.

One added track can still make a meaningful difference to a short clip. A restrained background helps establish mood; a clearly recorded voice can explain a sequence that would otherwise be ambiguous. Keep the audio's role in mind when deciding how loud it should be.

For complicated projects with precise cues, multiple speakers, or layered effects, use a timeline editor instead. This focused workflow is intended for the last straightforward soundtrack step, not for replacing a full sound-design workspace.