Write the scene, put the spoken lines in quotes, and get a video where the voices, the footsteps, the room tone and the music arrive together with the picture. No silent clip waiting for a voiceover, no separate sound pass, and no hunting for the frame where the lips should have matched.
Most AI video generators hand you a silent clip and leave the rest to you: find a voice, hunt for footsteps, pick a music track, then nudge everything until the mouths match the words. A newer group of models skips that chain. Dialogue, sound effects, ambient sound and music are generated in the same render as the picture, so a character says the line you wrote and the door slams when it closes.
The old workflow is a relay race. You generate a silent clip, record or synthesize a voiceover, layer sound effects on top, add a music bed, and then drag everything around a timeline until it feels right. Every handoff is a place where sync breaks. The mouth in the clip was animated for silence, so the voice you add later never quite lands on it, and the footsteps you found are always a half beat off.
A model that makes audio and picture in one pass changes the order of operations. It decides what the scene sounds like while it decides what the scene looks like, so rain comes with rain noise, a crowd comes with murmur, and a speaking character comes with a mouth that follows the words. Seedance 2.5, for example, is described in the catalog as generating synced dialogue, sound effects and background music in the same render as the video.
That does not make the separate chain obsolete. If you already have a silent clip, adding sound effects to a silent AI video is still the right job, and a long narration is better handled by an AI voiceover. But for short scenes where the picture and the sound belong together, one render saves you the whole relay. Picasso IA lists 121 text-to-video models among its 502, and the ones below are the four where the catalog says audio is part of the output.
All four run from the same workspace, so comparing them costs you a prompt, not a new account. The table below sticks to what the catalog states about each model and puts the older silent chain in the last row for contrast.
| Approach | Audio the catalog describes | Clip length and resolution | Good fit |
|---|---|---|---|
| Seedance 2.5 | Dialogue written in quotes, sound effects and music in one render, plus lip-sync to a reference voice clip | Up to 30 seconds, 480p or 720p | Scenes with spoken lines and a character who must stay consistent |
| Seedance 2.5 Lite | Synchronized audio on by default, switchable off | 5 or 10 seconds, 480p or 720p | Quick drafts and short beats you want to iterate on |
| Veo 3.1 | Context-aware audio matched to the scene | 4, 6 or 8 seconds, up to 1080p | Short, sharp shots where resolution matters |
| Gemini Omni 1.1 | Built-in audio, with "no dialogue" available as a prompt instruction | From a 360p draft mode up to 4K | Ambient scenes, and edits to an existing clip by instruction |
| Silent clip plus separate voice and effects | Each layer made in its own tool | Whatever the silent clip allows | An exact script read by a chosen voice, or a specific music track |
Read the table as a set of trade-offs, not a ranking. Seedance 2.5 is the longest and the most controllable for speech. Seedance 2.5 Lite is the one to open when you are testing ten versions of the same idea. Veo 3.1 gives you 1080p for short shots, and the Picasso IA vs Google Veo page covers how a one-model service compares with a catalog.
The goal here is a single clip you can listen to and judge, not a folder of silent drafts. It takes one idea and a pair of headphones.
Think of the prompt as four layers that all need an owner: what is said, what is heard on screen, what is heard in the room, and what plays underneath. Models fill any layer you leave empty with their own guess, which is sometimes lovely and sometimes a swelling orchestra under a quiet kitchen scene. If you want silence in a layer, say so: Gemini Omni 1.1 accepts an instruction such as no dialogue, and the same trick works in plain words on the others.
A prompt that covers all four reads like this: a woman in a yellow raincoat reaches the end of a stone pier, laughs and says "We made it to the lighthouse", waves slap the posts, gulls cry overhead, soft piano under the whole scene. The spoken line sits in quotes, the effects are named, and the music is described by mood instead of by title.
Tip: keep each clip to the lines it can carry. One short line per speaker lands better than a paragraph of speech, and a scene with two lines and a clear pause between them is easier to check than a scene where five sentences overlap.
For a recurring character, give the model something to hold on to. Seedance 2.5 takes up to 30 reference images to keep a face and outfit steady, and it accepts reference audio clips to drive lip-sync, as long as at least one reference image or video comes with them. Only use a voice you own or have permission to use, and only faces that are yours or fictional characters, never a real person who has not agreed to it. If you are building a character you will reuse, consistent AI characters walks through that part.
Most bad results trace back to the same few habits. Asking for too much speech in one clip is the first: the model squeezes the lines in and rushes them. Leaving the soundscape unspecified is the second, which hands the choice of music to the model. Writing the dialogue outside quotes is the third, because then it reads as a description of the scene instead of words to be spoken. And judging a clip with the sound off, or on laptop speakers in a noisy room, hides the problems you most need to catch.
A page about sound should be honest about what it cannot yet do. These five limits are the ones worth planning around:
None of this undoes the main benefit. It marks the point where a human edit or a dedicated audio model takes over from the generator.
Yes, with the right models. On Picasso IA, Seedance 2.5, Seedance 2.5 Lite, Veo 3.1 and Gemini Omni 1.1 all produce audio as part of the video, so you get a single file with the picture and the sound together. The catalog describes Seedance 2.5 as rendering dialogue, sound effects and music in the same pass as the video.
Four are covered here: Seedance 2.5, Seedance 2.5 Lite, Veo 3.1 and Gemini Omni 1.1. Each describes built-in or synchronized audio on its model page. The catalog holds 121 text-to-video models, and not all of them make sound, so check the model page before you assume. If a model lists a generate audio or save audio option, that is the setting that controls it.
Write the line inside double quotes in your prompt, and say who speaks it. Seedance 2.5 treats quoted text as dialogue and renders the mouth movement to match, so a prompt like the woman says "Welcome back" gives you a clip where she says it. Keep each line short, and listen to the result, because a quoted line is a strong instruction but not a guarantee of perfect pronunciation.
Yes. Seedance 2.5 and Veo 3.1 have a generate audio setting, and Seedance 2.5 Lite has a save audio setting that you can switch off for a silent clip. With Gemini Omni 1.1 you can write no dialogue in the prompt to keep speech out, though the model still builds in sound.
It depends on the model. Seedance 2.5 is described as producing clips of up to 30 seconds, Seedance 2.5 Lite offers 5 or 10 seconds, and Veo 3.1 offers 4, 6 or 8 seconds. Longer pieces are built from several clips.
It is good enough to be worth trying and not good enough to skip checking. Seedance 2.5 renders the mouth movement for lines you write in quotes, and it can sync to a reference voice clip. Fast speech, several people talking at once and unusual words are the places it slips. Watch the clip with sound on, and regenerate the take if a key line looks off.
With Seedance 2.5, yes: it accepts reference audio clips to drive lip-sync, as long as at least one reference image or video is supplied with them. Use only your own voice, or a voice you have permission to use. Cloning or imitating a real person who has not agreed to it is not something this page suggests, and for a voice that belongs to a fictional character you are free to describe it in the prompt instead.
When the exact words, the exact voice or the exact music matter more than sync convenience. A script read in a chosen voice, a long narration, or a specific track all point to the separate chain. You can generate the clip with audio off and add a voiceover and music yourself, which gives you independent control over each layer of the mix.
That is a different job from native audio. Native audio models generate sound while they generate the picture, so they do not simply score footage you already shot. For an existing silent clip, the better route is adding sound effects to silent AI videos with a dedicated model. Gemini Omni 1.1 can edit an existing video with a written instruction, but that is editing the picture.
Generation costs credits, and the amount depends on the model and the settings you choose, such as resolution and clip length. New accounts get free credits, which is enough to try a short test clip. Because prices and plans change, the numbers are not repeated here. The pricing page is the place to check what a Seedance 2.5 or Veo 3.1 run costs before you commit to a longer scene.
Your next scene already has a sound in mind, so open the Picasso IA toolkit, write the line in quotes and hear what comes back.
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