Seedance 2.1: Multimodal Inputs, Longer Videos, and Frame-Level Control

The Next Evolution

We are thrilled to announce that Seedance 2.1 — ByteDance's next-generation AI video model — will be available exclusively on Lumavo. This is not a minor update. Seedance 2.1 represents a fundamental leap forward in what AI video generation can do.

What Is Seedance 2.1?

Seedance 2.1 is the successor to Seedance 2.0, built on an entirely new architecture that ByteDance calls the MultiModal Video Transformer (MMVT). The model has been trained on a significantly larger and more diverse dataset, with a focus on solving the hardest problems in video generation: temporal consistency, character persistence, and fine-grained creative control.

Key New Features

1. 30-Second Video Generation

Seedance 2.0 capped out at 10 seconds. Seedance 2.1 triples that to 30 seconds — enough for full commercial spots, music video segments, and narrative scenes with multiple beats.

What changes: You can now tell complete stories in a single generation rather than stitching multiple 5-10 second clips together. The model maintains visual quality and coherence across the full 30-second duration. Credit cost: 40 credits/second for 720p Pro mode. A full 30-second clip at Pro quality costs 1,200 credits — roughly equivalent to three 10-second clips under Seedance 2.0, but with dramatically better consistency.

2. Multimodal Inputs (Text + Image + Audio)

Seedance 2.1 accepts text, images, and audio simultaneously as conditioning inputs:

• Text + Image: Provide a style reference image alongside your prompt for more controlled output
• Text + Audio: The model analyzes audio waveforms to sync motion to music beats or speech patterns
• Text + Image + Audio: The full multimodal stack — describe the scene, provide a visual reference, and let the model sync motion to your soundtrack

// Multimodal generation with Seedance 2.1
const response = await fetch("https://api.lumavo.com/v1/txt2video", {
  method: "POST",
  headers: {
    "Authorization": Bearer ${API_KEY},
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    model: "seedance-21",
    prompt: "A ballet dancer performing a slow, graceful routine in an empty theater. The choreography follows the music.",
    duration: 15,
    resolution: "720p",
    referenceImage: "https://cdn.example.com/dancer-costume-ref.jpg",
    audioUrl: "https://cdn.example.com/ballet-score.mp3",
    audioSync: "beat"     // Sync motion to musical beats
  })
});

The audio sync feature is particularly exciting for music video creators — the model detects BPM, downbeats, and intensity changes to choreograph motion automatically.

3. Frame-Level Editing

This is the most requested feature from professional creators. Seedance 2.1 exposes keyframes that you can edit individually:

• Keyframe insertion: Specify exact frames where you want compositional changes
• Interpolation control: Adjust how the model interpolates between keyframes (linear, ease-in-out, custom curve)
• Motion brush: Paint motion vectors directly on specific regions of a frame
• Inpainting: Fix artifacts in specific frames without regenerating the entire video

// Frame-level editing with keyframe insertion
const response = await fetch("https://api.lumavo.com/v1/txt2video", {
  method: "POST",
  headers: {
    "Authorization": Bearer ${API_KEY},
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    model: "seedance-21",
    prompt: "A camera flies through a futuristic city",
    duration: 10,
    keyframes: [
      {
        timestamp: 0,
        description: "Starting at ground level looking up at skyscrapers",
        cameraParams: { angle: "low", movement: "none" }
      },
      {
        timestamp: 5,
        description: "Mid-flight between towers, neon signs pass by",
        cameraParams: { angle: "level", movement: "dolly-forward" }
      },
      {
        timestamp: 10,
        description: "Ascending above clouds revealing the full skyline",
        cameraParams: { angle: "high", movement: "crane-up" }
      }
    ]
  })
});

4. Enhanced Prompt Adherence

Seedance 2.1's new MMVT architecture improves prompt adherence by approximately 40% over Seedance 2.0 based on internal benchmarks. The model now reliably handles:

• Complex multi-subject scenes (up to 5 distinct subjects interacting)
• Nuanced lighting instructions ("split lighting with warm key and cool fill")
• Camera lens specifications ("85mm portrait lens at f/1.4")
• Emotional tone descriptions ("melancholic atmosphere", "joyful energy")
• Negative prompts with higher specificity ("no motion blur, no face distortion, no floating objects")

5. Superior Temporal Consistency

Seedance 2.1 introduces Temporal Consistency Modules (TCM) — dedicated attention layers that cross-reference frames across the entire video sequence, not just adjacent frames. This means:

• Characters maintain consistent appearance from frame 1 to frame 300
• Lighting changes are smooth and physically plausible
• Objects do not morph or "drift" over time
• Background elements stay locked in place

Early testing shows that character consistency at 30 seconds in Seedance 2.1 is better than Seedance 2.0 at 5 seconds.

6. Improved Multilingual Prompt Understanding

Seedance 2.1 has been trained on prompts in 12+ languages including English, Chinese, Japanese, Korean, Spanish, French, German, and Arabic. Non-English prompts now achieve quality comparable to English prompts — a significant improvement over 2.0 which showed a noticeable quality gap.

7. 4K Native Output

Seedance 2.0 required a separate upscale step for 4K. Seedance 2.1 supports native 4K output at 80 credits/second, eliminating the upscale pass and delivering cleaner results with better detail retention.

Performance Benchmarks

Metric	Seedance 2.0	Seedance 2.1	Improvement

Max Duration	10s	30s	3x
Prompt Adherence	82%	91%	+11%
Character Consistency (10s)	78/100	94/100	+21%
Motion Naturalness	7.8/10	8.9/10	+14%
Avg Gen Time (5s 720p)	38s	32s	16% faster
Multilingual Quality Gap	-15%	-3%	80% reduction

Backward Compatibility

All existing Seedance 2.0 API calls will continue to work. Seedance 2.1 is accessed via the model parameter seedance-21. To upgrade an existing integration, simply change:

- "model": "seedance-20"
+ "model": "seedance-21"

Your existing prompts will work, but we recommend adding camera and audio instructions to take full advantage of the new capabilities.

Pricing

Seedance 2.1 pricing on Lumavo:

Quality	Resolution	Credits/Second

Pro	720p	40 cr
Pro	1080p	60 cr
Pro	4K Native	80 cr
Fast	480p	14 cr
Fast	720p	24 cr

Existing Seedance 2.0 pricing is unchanged. Both models are available side-by-side so you can choose based on your needs and budget.

Availability

Seedance 2.1 will be available on Lumavo in the coming weeks. We are in the final integration and testing phase with ByteDance. All Lumavo users will get access on launch day — no additional sign-up or approval required.

What About Kling and HappyHorse?

Seedance 2.1 is the first of several major model updates coming to Lumavo this year. We continue to work closely with Kuaishou, Alibaba, and other AI labs to bring their latest models to the platform. Our commitment to being model-agnostic means you will always have access to the best model for your specific use case — not just the one we built.

Get Ready

To prepare for Seedance 2.1:

1. Stock up on credits — 30-second generations at Pro quality cost 1,200 credits. The [XL Pack](/pricing) offers the best value for heavy users
2. Prepare your multimodal assets — Start collecting reference images and audio tracks you want to use
3. Plan your keyframe sequences — Frame-level editing rewards pre-production planning
4. Follow our updates — Subscribe to the [Lumavo newsletter](/about) for launch announcements

The team at Lumavo cannot wait to see what you will create with Seedance 2.1.