Add sound to video
Add Sound to Video with AI: Effects, Music and Voiceover
Add audio to a silent video in one pass: AI sound effects matched to the picture, music that follows your cuts, and a voiceover or dialogue in 35 languages.
- 1Upload a silent clip
- 2Pick effects, music and voices
- 3Download one MP4
- 1Upload a silent clip
- 2Pick effects, music and voices
- 3Download one MP4
Kling 3 4K · cinematic
Veo 3.1 native audio
Seedance 2 #1 arena
Wan 2.7 image-to-video
Hailuo 2.3 expressive
Hunyuan open sourceKling 3 4K · cinematicVeo 3.1 native audioSeedance 2 #1 arenaWan 2.7 image-to-videoHailuo 2.3 expressiveHunyuan open sourceWhy add sound to a silent video with AI
Sound is half of how a clip lands. Most tools add one piece: a sound effect, a stock track, or a voice-over. This one adds all three to the video you already have.
An AI sound effects generator plus music and voiceover
Effects, music and voices in a single pass, mixed and ready to download.
Sound effects matched to the action
Ambience and action sounds generated from what's on screen, plus any off-screen sounds you describe.
Music in six moods
Cinematic, upbeat, calm, tense, lo-fi or epic, scored to your clip and ducked under speech.
Narration or dialogue in 35 languages
Ten voices plus your own cloned voice. One voice per speaker, kept consistent through the clip.
AI-written script
AI watches your video and writes short, timed lines you can edit before generating.
Keep existing speech
Already have dialogue? Keep it and build the sound effects around it.
Who adds sound with OnVid
From silent AI clips to product demos and short stories.
AI video creators
Clips from many AI video models come out silent. Give them real sound before you post.
Every leading video model, one studio
Match the right engine to each idea — no extra accounts, no juggling tools.
Cinematic 4K text-to-video with native audio and multi-shot consistency.
The only model with synchronized dialogue and sound.
Film-grade generation with strong prompt adherence and synced audio.
Sharp, physically accurate motion in crisp 4K.
Native 2K motion with synced audio and omni-reference — the Hailuo 3 generation.
Expressive, characterful motion with lively faces.
Black Forest Labs' unified image + video + audio model, with clips up to ~20 seconds.
Native 4K clips up to 30s with synced sound.
Fast clips with synced native audio.
| Model | Resolution | Max length | Best for | Speed |
|---|---|---|---|---|
| 1080p | 5s / 10s | Cinematic, multi-shot | Max quality | |
| 720p / 1080p / 4K | 8s | Native audio | Balanced | |
S2 Sora 2 | 720p / 1080p | 4s / 8s / 12s | Prompt adherence | Balanced |
| 480p / 720p / 1080p | 5s / 10s | Sharp motion | Fast | |
| 768p / 2K | 5s / 10s | 2K detail with sound | Balanced | |
| 768p | 6s / 10s | Expressive motion | Fast | |
| 1080p+ | ~20s | Unified multimodal | Max quality | |
| 480p / 720p / 1080p | 5s / 10s | References + video remix | Fast | |
| 480p / 720p | 6s | Fast clips with sound | Balanced |
How to add sound to a video in three steps
No editing timeline, no sound library to search.
Upload your video
Drop in a silent MP4 or MOV up to 60 seconds. It can be phone footage, a screen recording or a clip from any AI video generator.
Kling 35s10s16:9Choose what to add
Sound effects are always included. Add music and pick a mood, add voices and type or auto-write the lines, and choose the language.
Download the result
In about a minute you get one MP4 with everything mixed. Not quite right? Change a line or the mood and run it again.
How do you add sound to a silent video?
What the tool does, what it doesn't, and how to get the best result.
Is there an AI that adds sound effects and voices to a silent video?
Yes. OnVid's Audio Studio takes a silent or near-silent video you upload and returns it with three optional layers: AI sound effects and ambience matched to the action on screen, a music track scored to the clip, and spoken narration or dialogue in 35 languages. Most other tools only cover one of these, or only work on clips they generate themselves. Here you start from your own footage, choose the layers, and download a single mixed MP4.
How does an AI sound effects generator match the picture?
A video-to-audio model looks at every frame and generates sound for what it sees: a door closing, rain on a window, a car passing, a crowd cheering. The sounds are timed to the movement, so a footstep lands when the foot hits the ground. You can also type a hint for sounds the camera doesn't show, such as distant thunder or a radio in the next room.
How do you add a voiceover to a video without recording?
To add a voiceover to a video, turn on Voice and choose Narrator or Characters. Type your lines and set when each one starts, or press Write it for me: the AI watches the clip and drafts short, timed lines in the language you pick, which you can edit before generating. Each speaker gets a distinct voice. Voices are placed over the video; mouths on screen are not lip-synced, so narration and off-screen speech work best.
Can you add music to a video at the same time?
Yes. To add music to a video, switch on Music and pick a mood: cinematic, upbeat, calm, tense, lo-fi or epic. The track is generated for your clip, so it follows its length and pacing instead of being cut off mid-phrase. When voices are on, the music automatically drops lower while someone speaks.
What videos work best?
Clips up to 60 seconds in MP4 or MOV with clear, visible action get the most convincing sound: people walking, waves, city streets, cooking, sports, animals, AI-generated scenes. If your video already has speech you want to keep, tick Keep speech that's already in the video and the new sound is built around it.
How to add audio to video online with AI
Most ways to add audio to video assume you already have the audio: a song, a recorded voice, a sound effect pack. OnVid makes the audio for you from the video itself. Upload the clip, keep sound effects on, add music and a voiceover if you want them, and press Add sound. The effects are generated from what happens on screen, the music is scored to the length and cuts of your clip, and the voice lines are placed where you set them. Everything is mixed into one track, with the music and effects turned down while someone speaks, so you don't need an editing timeline or a sound library.
Add sound to AI-generated videos
Many AI video models return silent clips, and others add sound you can't control. If you made a clip with an AI video generator and it came out silent, run it through Add sound before you post it: footsteps, wind, traffic, crowd noise or a door closing are added where they happen, and you can describe the mood you want for the music. It works the same on phone footage, screen recordings and product shots. If your clip already has speech you want to keep, tick Keep speech that's already in the video.
Made with OnVid
Real clips generated from a single prompt — hover any card to play.
MiniMax H3Seedance 2Kling 3Seedance 2.0Adding sound to video, answered
Limits, pricing and what to expect.
Is there an AI that adds sound effects and voices to a silent video?
Yes. OnVid's Audio Studio adds AI sound effects, optional music and optional narration or dialogue in 35 languages to a video you upload, and returns one mixed MP4.
How long can my video be to add sound?
Up to 60 seconds, in MP4 or MOV format.
Are the AI voices lip-synced to the video?
No. Voices are placed over the video at the times you set. Narration and off-screen dialogue work best.
Which languages can the voiceover use?
35, including English, Spanish, Portuguese, German, French, Italian, Turkish, Ukrainian, Arabic, Hindi, Japanese, Korean and Chinese.
Can AI write the narration for my video?
Yes. Press Write it for me and the AI watches your clip and drafts timed lines in your chosen language. You can edit every line before generating.
Can I use my own voice for the voiceover?
Yes. If you have cloned your voice in OnVid, it appears in the voice list next to the ten built-in voices.
What if my video already has some audio?
Tick Keep speech that's already in the video and the new sound effects are generated around the existing speech. Otherwise the original audio is replaced.
How much does it cost to add sound to a video?
It uses credits from a Pro or Max plan, charged per second of video: 30 credits per second for sound effects, plus 24 for music and 10 for voices. Clips shorter than 5 seconds are billed as 5. You see the exact credits before you generate.
Is there a free way to add sound to a video with OnVid?
You can create a free account and set everything up, but generating requires a Pro or Max plan.
Can I use videos with AI sound commercially?
Yes, the sound effects, music and voices generated for your video can be used in your own commercial and social content. You are responsible for the rights to the footage you upload.
How do I add audio to a video with AI?
Upload the video, choose sound effects (always on), music and a voiceover if you want them, and press Add sound. OnVid generates the audio from the picture and mixes it into one MP4, usually in about a minute.
Can I add music to a video without finding a song?
Yes. Turn on Music and pick a mood. The track is generated for your clip, follows its length and cuts, and gets quieter under any voiceover.
Is this an AI sound effects generator?
Yes, for video. Instead of typing a sound and downloading a file, you upload a clip and the AI generates sound effects and ambience timed to what happens on screen. You can also describe extra sounds, like distant thunder.
Can I add a voiceover to a video in another language?
Yes. Choose one of 35 languages and type the lines or let AI write them. To change the language of a video that already has speech, use the AI video translator instead.
Silent clip in, finished video out
Sound effects, music and voices for the video you already have.