Native audio
AI video generator with sound, and what that phrase means
An AI video generator with sound generates the picture and the audio together in one pass, which only Veo 3 and Sora 2 currently do well. If what you want is sound added to a video you already have, that is a separate kind of tool and this page will not help you find it.
This phrase gets used for two completely different products. One generates a clip that arrives with its own audio track. The other takes a finished video and produces effects to sit under it. The search results mix them freely, so the first job of this page is to separate them, and the second is to say honestly how well the first one currently works.
Two different tools
| Native audio generation | Sound added to existing video | |
|---|---|---|
| What you start with | A prompt | A finished video file |
| What the model does | Generates frames and audio in one pass | Watches the video and produces effects to match |
| Alignment | Tight, because both came from the same generation | Approximate, and you nudge it on the timeline |
| Typical output | Ambience, effects, sometimes speech | Effects and stings |
| Length limit | Around eight seconds | Whatever your video is |
Which models emit audio
| Model | Ambience | Effects | Dialogue | Notes |
|---|---|---|---|---|
| Veo 3 | Yes | Yes | Yes, with weak lip sync | The most complete native audio available. Ambience is the strongest part. |
| Sora 2 | Yes | Yes | Yes, with the same lip sync problem | Strong scene sound. Access is the constraint rather than quality. |
| Kling 2.5 | No | No | No | Silent. Strong picture, especially from an image input. |
| Seedance 2.0 | No | No | No | Silent. Good at motion and vertical framing. |
| Wan 2.5 | No | No | No | Silent. Best on texture and atmosphere. |
Hear the difference
Turn the sound on for these. The first two arrived with their audio. The third is a silent generation with audio added afterwards, included so you can hear what the gap sounds like.
The eight second ceiling
Native audio generations are short, and the audio is the reason. Picture quality holds reasonably well as a clip runs on. Audio does not. Ambience starts to loop audibly, effects lose their relationship to what is on screen, and any speech drifts further out of sync with every second.
The practical consequence is that native audio is a single shot feature. It is excellent for one clip that has to feel real on its own. It is the wrong choice for a video assembled from eight generations, because each one arrives with its own room tone and the cuts between them are audible. For assembled videos, generate silent and build one continuous audio bed underneath.
Why generated speech does not lip sync
The model produces the mouth shapes and the sound from the same prompt, but nothing forces them to agree frame by frame. A dedicated lip sync system works the other way round: it takes an audio track as fixed and drives the mouth from it. A generative model has no such constraint, so it produces a mouth that is roughly talking and audio that is roughly the right words, and the two land a few frames apart.
A few frames is enough. Viewers detect lip sync error better than almost any other artefact in video, which is why generated dialogue reads as wrong even when the picture is excellent. If your video needs someone speaking on camera, use a lip sync tool over a recorded voice, or avoid the shot and put the words in a voiceover, which is the approach on the script to video page.
When to use which
- One hero shot that must feel real. Native audio. The alignment between picture and sound is the thing you cannot fake quickly.
- A cut sequence. Silent generations, one audio bed built underneath. Cheaper, more consistent, and you keep control of the mix.
- Anything with speech. Separate voice track. Always.
- Social posts. Something has to be playing. Native audio if the shot has a sound worth having, music if it does not. Details on the vertical format page.
Where this fits
Sound is one capability of a modern video AI generator, and it is the one changing fastest. If you are choosing between models on cost rather than capability, the free tier arithmetic is on the free comparison page.
Prompting for sound
On a model that emits audio, what you write changes what you hear as well as what you see. Most people describe only the picture and then wonder why the audio is thin.
- Name the environment. A narrow stone alley and an open field produce different reverb even with the same action in them.
- Name the materials. Footsteps on gravel, on wood, on wet tarmac. The model has heard the difference.
- Say what is off screen. Traffic in the distance, a kettle in the next room. Ambience you cannot see is what makes a clip sound real.
- Keep dialogue to one short line. The longer the speech, the further the lip sync drifts. Six words is about the limit.
- Ask for quiet when you want quiet. No music, no dialogue, room tone only. Models fill silence otherwise.
Building an audio bed for a cut sequence
Once you are assembling clips, native audio becomes a liability rather than a feature, because each generation carries its own room. The fix is four layers built underneath the whole timeline.
One continuous ambience
A single background track running the full length. It is what makes eight separately generated clips feel like one place.
Effects on the moments that need them
Not on every cut. Two or three placed on real actions do more than a full sound pass, and they cover the joins.
Voice on top, mixed loudest
If there is narration, everything else exists to support it. Duck the bed under the voice rather than turning the voice up.
Music last, or not at all
Music added first tends to dictate the edit. Added last it fills the gaps. Plenty of good short videos have none.
If you generated with native audio and then decided to cut the clips together, strip the generated audio and rebuild it this way. Keeping four different room tones and crossfading between them takes longer than starting again.
Sound problems and what causes them
| What you hear | Cause | Fix |
|---|---|---|
| The room changes at every cut | Each generation produced its own ambience | Strip the generated audio and lay one continuous bed |
| Speech sounds dubbed | Lip sync drift, which is inherent to generated dialogue | Use a separate voice track, or keep the mouth out of frame |
| Audible loop in the ambience | The clip ran longer than the audio stays coherent | Cut shorter, or replace the audio entirely |
| Effects land slightly late | Loose alignment between the two outputs | Nudge on the timeline, or re generate at a shorter length |
| Everything is too quiet | Generated audio often arrives well below broadcast levels | Normalise every clip on import before you judge the mix |
The other kind of tool, briefly
Since half the results for this phrase are tools that add sound to a video you already have, here is what they do, so you can tell within a sentence whether a page is offering you one.
| Product | Input | Output | When you want it |
|---|---|---|---|
| Video to sound effects | A finished clip | Effects timed to what it sees | You generated silent footage and need the actions to land |
| Text to sound effects | A description | A single effect or ambience file | You need one specific sound that is not in a library |
| Text to music | A description or a mood | A music bed of a chosen length | You need a bed and cannot licence one |
All three are useful and none of them is a video generator. If you are assembling a cut from silent generations, the first and third are what you actually want, layered as described above.
Levels
Generated audio arrives quiet and inconsistent between runs, which is easy to miss on headphones and obvious on a phone speaker. Normalise every clip on import before you make any decision about the mix, otherwise you will spend an hour balancing clips against each other and then have to redo it.
Set the voice as your reference and place everything else relative to it. Ambience wants to sit well under the voice, effects wants to peak briefly and get out of the way, music wants to be quieter than feels right while you are mixing it, because it always sounds louder on someone else's device.
Where this is heading
Native audio is the newest capability in this category and the one changing fastest. Two years ago no consumer model emitted sound at all. Today two do it well enough that a single shot needs no audio work. The obvious next steps are longer coherent audio and enforced lip sync, and neither is solved yet, which is why this page is written the way it is rather than as a feature list.
Sound questions
Which AI video generators produce sound?
Veo 3 and Sora 2 emit audio as part of the generation, including ambience, effects and some dialogue. Kling, Seedance and Wan generate silent video, so anything they make needs an audio pass afterwards.
What is the difference between native audio and adding sound later?
Native audio is generated with the picture by the same model, so it lines up with what happens on screen. Adding sound later means a separate tool analyses a finished video and produces effects for it, which is a different product and a different search.
How long can a clip with generated sound be?
Around eight seconds is the working ceiling on current native audio generations, and the audio degrades before the picture does. Longer videos need the audio built separately and laid over the cut.
Why does generated dialogue look badly dubbed?
The model generates the mouth and the sound from the same prompt but does not enforce a strict match between them. Small timing errors read as dubbing because human viewers are extremely sensitive to lip sync, far more than to any other audio error.
Can I get music from a video generator?
Not usefully. Native audio produces the sound of the scene, so footsteps, wind, room tone, traffic. Music is a separate generation and belongs on your timeline rather than inside the clip.
Should I use native audio or add my own?
Use native audio for single shots where the sound of the scene is the point. Use your own audio for anything cut together from several clips, because native audio does not match across generations and every cut will sound like a jump.
Does generated sound come with the same licence as the video?
It is part of the same output file and falls under the same terms as the video from the tool you generated with. Check those terms, because they differ between tools and between free and paid tiers.