Best AI video generators with audio

Key takeaways

• Melius is the pick when one video needs several kinds of sound, because one subscription covers the leading native-audio video, voice, lip-sync and music models. Mel, the Melius agent, matches each part of your brief to the right one.
• Google Veo 3.1 generates dialogue, sound effects and ambient sound with the picture, and Flow gives every user free credits each day.
• Kling 3.0 handles multi-character dialogue in five languages, and its Lip Sync tool matches a face to audio you upload.
• HeyGen and Hedra are lip-sync tools first. Give HeyGen a script or a recording, or Hedra a recording, and an avatar or a portrait speaks it.
• LTX-2.5 is the open-weights option, generating picture and stereo sound in a single pass.

Which AI video generator has the best audio?

The best AI video generator with audio depends on which sound you need. For dialogue, effects and ambience generated with the picture, Google's Veo 3.1 and Kling 3.0 lead. For lip sync to a voice you've already recorded, HeyGen and Hedra are built for exactly that. Melius suits projects that need all of them, because it puts leading models for each kind of sound in one place, and Mel sends each shot and each track to the one suited to it.

We split audio into five jobs: native sound generated with the picture, dialogue in more than one language, lip sync to audio you supply, voiceover from a script, and sound effects and music. Then we ranked these six on how many of those jobs each tool does well, how long a clip can run with sound, and how much control you keep over the mix. Price isn't a ranking factor here, because plans change often.

What to know before you pick

• Native audio is generated in the same pass as the picture. That's what keeps footsteps on the beat and lips on the line. Sound added afterward is easier to control, but you have to sync it.
• Lip sync to your own audio is a separate feature. Native-audio models generate the voice. Lip-sync tools take a recording you already have and animate a face to match it.
• Clips with sound are short. Veo 3.1 runs 4, 6 or 8 seconds per generation, and longer scenes are chained extensions. Talking-head tools run for minutes because the audio sets the length.
• Speech is the hardest part. Google DeepMind's own Veo page says natural, consistent speech in shorter segments is still an area of active development, so plan for a few rerolls on dialogue.
• Keep tracks separate if the mix will change. If the music or the voiceover might be replaced later, generate it as its own track instead of baking it into the clip.

The six compared

Melius: the leading audio models, matched to each job

Melius is the AI-native operating system for creatives. You brief Mel, the Melius agent, with the script and the shots you want, and Mel builds the project on one canvas.

What sets Melius apart on sound is the range of models behind it. A single-model tool gives you that model's audio, whether it's strong at dialogue or not. Our library of leading models covers every part of the mix. For native sound there's Seedance 2.5, which makes high-motion clips with synchronized audio, plus LTX 2.5 and Wan 3.0, with Wan running up to 30 seconds. Voiceover comes from ElevenLabs and other voice models; lip sync to a recording from Kling Lipsync, HeyGen Lipsync or Sync Lipsync v3; music and effects from ElevenLabs and Sonilo. The voiceover, the lip sync and the score in one video can each come from a different model, picked because it does that job well.

Mel does the routing. It picks the model for each step, writes the prompts and wires the nodes together, so you don't need to know each model's input limits or which one handles dialogue best. You stay the director: every step sits on the canvas as a node, and when a line read is off you tell Mel, or ask it to try that shot on another model, and the rest of the project stays as it is.

What Melius does well

• Puts native-audio video, voice, lip-sync, music and effects models under one subscription, so every track comes from a model built for it.
• Runs the same shot through more than one native-audio or lip-sync model when you ask, so you can keep the take that sounds best.
• Lip syncs a shot to your own recording once you drop the file onto the canvas and ask Mel.
• The agent chooses and connects the models, so you get the right one for each step without learning each one's strengths.
• Keeps every step editable, so a wrong line read is one note to Mel or one change on one audio node.

The trade-off with Melius

Length and sound quality vary from model to model, so a video built from several models needs a listen-through to check that voices and levels match from shot to shot.

Best for: creators and teams who want the best model for each part of the sound, from dialogue to score, in one video.

Google Veo 3.1: sound generated with every clip

Veo 3.1 is Google DeepMind's dedicated video model, available in Flow, Google Vids and the Gemini API; in the Gemini app, Google's newer Gemini Omni model has replaced it. It generates sound effects, ambient noise and dialogue with the picture, so a prompt that describes a line of dialogue or a door slamming returns a clip with both. It comes in Lite, Fast and Quality variants.

What Veo 3.1 does well

• Generates dialogue, effects and ambience in a single pass.
• Outputs at 1080p and 4K.
• Gives every Flow user free credits each day.

The trade-off with Veo 3.1

Each generation runs 4, 6 or 8 seconds, so a longer scene is a chain of extensions. Veo doesn't lip sync to audio you supply, and speech in short segments is still the weakest part of its sound.

Best for: short cinematic clips where the sound has to arrive with the shot.

Kling 3.0: multilingual dialogue and lip sync

Kling is Kuaishou's AI video platform. Kling 3.0, released in February 2026, generates speech natively in English, Chinese, Japanese, Korean and Spanish, and several characters can speak in one scene, each in a different language, with control over what they say and in what order. Kling 4.0 was announced on September 28, 2026 and is still rolling out.

What Kling 3.0 does well

• Handles multi-character dialogue, shot-reverse-shot scenes and voiceover across several shots.
• Runs clips up to 15 seconds with audio.
• Matches a face to your own voiceover or song with its Lip Sync tool, or to built-in text to speech.

The trade-off with Kling 3.0

Lip sync needs the face fully visible in the shot. Kling's free plan comes with low-resolution, watermarked output, so serious work needs a paid plan.

Best for: dialogue scenes with more than one speaker or more than one language.

HeyGen: avatars that speak your script

HeyGen is an AI avatar video platform. Write a script or upload audio and an avatar delivers it, with lip sync HeyGen describes as phoneme-level. Its Avatar V model builds a digital twin from a 15-second webcam clip, and its video translation re-voices and re-syncs a video into another language.

What HeyGen does well

• Turns a script into a voiced, lip-synced presenter, with voice cloning available on the free plan and more clones on paid plans.
• Translates with lip sync in 175+ languages and dialects on paid plans, and in a smaller set on the free plan.
• Runs long: up to 30 minutes per video on the Creator plan.

The trade-off with HeyGen

HeyGen's strength is talking-head video. Its newer HeyGen Video model generates short scenes with dialogue, ambience and effects, but only 5 to 15 seconds at a time and through the API, so it isn't the tool for a full sound mix. The free plan is limited to a few short videos a month, with a watermark.

Best for: explainers, training and translated videos where a presenter carries the message.

LTX-2.5: open weights with sound

LTX-2.5, released on August 11, 2026, generates audio and video together in one model pass, as 24 kHz stereo. It also works the other way round: audio-to-video lets your voice, music or effects drive the picture, and a LipDub workflow, validated so far on LTX-2.3, redubs existing footage with new dialogue. You can run it through the LTX API, the free LTX Desktop editor, LTX Studio, or as open weights.

What LTX-2.5 does well

• Generates up to 20 seconds at a time.
• Outputs 1080p, 1440p and native 4K at up to 50 fps, including portrait up to 1080x1920.
• Is free to run as open weights for organizations under $10M in annual revenue.

The trade-off with LTX-2.5

Running it locally takes serious hardware: LTX Desktop asks for an NVIDIA GPU with 15GB+ of VRAM or an Apple Silicon Mac with 32GB+ of memory. The license isn't open source in the usual sense, since organizations above $10M in revenue need a commercial license. Which languages its dialogue supports isn't documented.

Best for: developers and studios that want audio and video generation on their own hardware.

Hedra: a talking character from one image

Hedra Avatar, which Hedra calls its latest longform avatar model, animates a single portrait to an audio track you upload. Lip sync follows the speech sound by sound and covers dialogue, explainers and singing in multiple languages, and the clip runs as long as the audio, up to 10 minutes.

What Hedra does well

• Starts from one image and one audio file.
• Outputs at 540p, 720p or 1080p.
• Has a free plan with no credit card required.

The trade-off with Hedra

Hedra needs the audio, and quality depends on a clean recording and a well-lit, front-facing portrait. Hedra Avatar doesn't generate effects or music, and the company now leads with inference infrastructure, with its creative Studio one product among several.

Best for: a host or character speaking a recorded track, from a single still.

Native audio or sound added afterward?

Native audio is the faster route to a clip that feels finished, because the sound is timed to the motion as it's generated. A glass breaking lands on the frame where it breaks. The cost is control: you can't swap the music or soften one effect without regenerating the clip.

Sound added afterward is slower but editable. A voiceover generated on its own track can be rewritten line by line, a lip-sync model can match a face to a recording you've approved, and effects can be placed and mixed by hand. Most finished videos use both: native sound for the shots where timing matters, separate tracks for the voice and the music.

Making a video with sound on Melius

Most projects on Melius start with a brief to Mel and end with a few notes back. A brief that gets the sound right covers these points.

1. Paste the script and say who speaks. Name or describe the voice, and say which shots carry dialogue and which are voiceover.
2. Describe the sound of each shot. Rain on a window, a crowd, footsteps on gravel. Mel sends those shots to a video model that generates sound.
3. Name a model if you have one in mind. Otherwise Mel picks one for each step, and you can ask it to rerun a shot on another model to compare.
4. Bring your own recording if you have one. Drop the audio file onto the canvas, then ask Mel to lip sync the shot to it.
5. Ask for music and effects on their own tracks if the mix might change later, so a new score doesn't mean regenerating the clips.
6. Review, then direct. Play the result and tell Mel what to change, or open the one node that's off. Finish in the multi-track editor, where you set each clip's volume and export the cut as MP4.

For the shots themselves, see AI video generators for filmmakers, compared. For the voice, see how to turn a script into a natural voiceover.

Frequently asked questions

Have a scene that needs sound? Open Melius, brief Mel with the script and the shots, and let it pick the right model for each part of the mix.