Add Audio to Video
Lays a separate audio file over the video.
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A NEW LAYER OF SOUND FOR YOUR VIDEO.
Add Audio to Video lays a separate audio file over your video. There are two methods: “Replace the video's audio” drops the old sound and puts the new one in its place (music beds, voice-over); “Hear both together” keeps the old sound and mixes the new one over it (background music). The level of the added sound is set between 0% and 200%; if the audio is longer than the video, the excess is cut. As the audio file you can upload MP3, WAV, M4A, AAC, OGG, Opus or FLAC.
The picture is not re-encoded: the job takes seconds and the source quality is preserved. A royalty-free option (MP3 / Opus) is recommended for the audio codec; for the widest device compatibility you can choose AAC. With MKV and WebM output, Opus is used with either choice, because those containers do not carry AAC. MP4, MOV, MKV, AVI, WebM and M4V files can be uploaded up to 10 GB.
From start to finish
- Upload the video and the audio. Add the video first, then the audio file. The duration and format of both are read.
- Choose the method and the level. Replace the sound or hear both together; set the level of the added sound as a percentage and choose the audio codec.
- Join and download. The picture is copied and the audio is mixed; it is ready within seconds. Download it; the copies on the server are deleted when you leave the tool.
Frequently asked questions
The music is drowning out the speech; what should I do?
If you chose “Hear both together”, bring the level of the added sound down to 30–50%: the background music then sits under the speech. If the speech itself is quiet, first prepare the sound with the “Audio Volume Normalizer” and add it afterwards.
What happens if the audio is shorter than the video?
The sound stops where it ends; the rest of the video continues with the old audio (in hear-both mode) or in silence (in replace mode). There is no looping; if you need a longer piece, first join the piece to itself with the “Audio Merger”.
Can I start the audio at a particular second?
This tool lays the audio on from the start of the video. If you want an offset, you can add silence to the beginning of the audio file, or take the part of the sound you want with “Audio Crop” and add that.
Does my file stay on the server?
No. Your file reaches the server only to be processed and is deleted when the job is done; the output is deleted too once you download it and leave the tool. You don't need an account, a name or an email address, and your files are never sent to a third-party service. It is free to use: we set no hourly or daily quota on the number of jobs, we don't make you watch an ad before processing, and we add no watermark to the output.
Other Video tools
- Video Converter — Converts your video to the format you want; sets the resolution and frame rate in the same pass.
- Video Compressor — Re-encodes to a target size or quality and verifies the output.
- Video Cutter — Place as many cut points as you like and cut them all at once.
- Video Merger — Joins multiple videos end to end into a single file.
- Video to Images — Extracts frames from a video, shows them as a gallery and lets you download them as a ZIP.
- Video → MP3 — Gives you a video's audio as an MP3 file.
- Video → WAV — Exports the video's audio as lossless WAV.
- Video → GIF — Turns the range you pick into a looping GIF.
- Video → WebM — Produces lightweight WebM output for the web.
- Video → MP4 — Converts to MP4, which plays everywhere.
- MOV → MP4 — Converts iPhone and Mac MOV videos to MP4 that opens everywhere.
- MKV → MP4 — Converts MKV videos to MP4 that opens on phones, TVs and in editing programs.
- AVI → MP4 — Converts old AVI videos to MP4 that opens on today's devices.
- WebM → MP4 — Converts WebM videos to MP4 that opens on the iPhone and in presentation programs.
- Video Resizer — Scales the resolution to the size you want.
- Video Crop — Crops out the part of the frame you don't want.
- Aspect Ratio Converter — 16:9, 9:16, 1:1 — reframes for each platform.
- FPS Converter — Changes the frame rate to adjust smoothness or file size.
- Rotate Video — Rotates the video by 90, 180 or 270 degrees.
- Mirror Video — Flips the picture horizontally or vertically.
- Reverse Video — Plays your video from the end to the beginning.
- Loop Video — Repeats your video back to back; nothing is re-encoded.
- Split Video — Splits your video into equal parts or into fixed-length segments.
- Video Colour Adjust — Adjusts brightness, contrast, saturation and gamma.
- Video Filter — Applies ready-made looks such as black and white, sepia or negative.
- Video Quality Enhancer — Reduces noise and cleans up the picture.
- Add Text to Video — Burns text onto your video.
- Add Logo / Watermark to Video — Overlays your own image on the video.
- Add Subtitles to Video — Burns an SRT or VTT subtitle file permanently into the video picture.
- Edit Video — Trim, crop and rotate — all in one pass.
- Edit GIF — Shrinks a GIF, changes its speed, takes a section out of it.
- Mute Video — Silences the audio track completely.
- Remove Audio from Video — Removes the audio track from the file entirely.
- Speed Up Video — Increases playback speed and shortens the duration.
- Slow Down Video — Lowers playback speed for a slow-motion effect.
- Video Metadata — Reads codec, duration and resolution; removes tags.
- Frame Extractor — Exports every frame in the range as a PNG, JPG or WebP file.
- Video Thumbnail Extractor — Lets you pick the frame to use as a thumbnail and exports it as an image.
- Video Frame Analysis — Measures the change between frames and shows scene boundaries.
- Silence Remover — Finds the silences between speech and cuts them automatically.
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