You've generated a video that's almost perfect — but it needs to be longer, or there's one element that doesn't belong, or you need to add a character that wasn't in the original. In previous-generation AI video tools, your only option was to start over from scratch and hope the new generation captured what the first one got right. Seedance 2.0 changes that fundamentally.

Seedance 2.0 — ByteDance's multimodal AI video model, available through Dreamina and inside Agent Opus — introduces two capabilities that transform AI video from a one-shot gamble into an iterative creative process: video extension and video editing. Extension lets you smoothly continue any existing video, stretching its timeline without breaking visual continuity. Editing lets you modify specific elements within an existing video — replace a character, remove an object, add a new element — while keeping everything else untouched.

These aren't minor features. They're the difference between AI video as a novelty and AI video as a production tool. Real creative work is iterative. It requires revision, extension, and selective editing. Seedance 2.0 finally makes that possible.

Video Extension: Seamless Continuation of Any Video

Video extension is conceptually simple: you have a video, and you want it to keep going. But the technical challenge is enormous. The extended portion needs to maintain the same visual style, lighting, subject appearance, camera movement trajectory, background consistency, and narrative logic. Any discontinuity between the original and the extension breaks the illusion.

Seedance 2.0 handles this through its deep understanding of temporal visual coherence. When you upload a video for extension, the model analyzes the existing footage comprehensively — not just the final frame, but the entire trajectory of movement, lighting, and composition. The extension then continues from that trajectory, not just from the last frame's static appearance. This is why the extensions feel smooth rather than stitched.

How Video Extension Works Technically

The base generation window for Seedance 2.0 is 4 to 15 seconds. With extension, you can chain multiple generations together, each one continuing smoothly from the previous output. There's no hard limit on how many times you can extend, though each extension adds another 4-15 second segment.

Crucially, you can provide new text prompts with each extension. This means you can evolve the narrative as you extend. The first generation might be a wide establishing shot. The extension might introduce a camera push-in. The next extension might shift to a detail close-up. Each step maintains visual continuity while the creative direction evolves.

Step-by-Step: Extending an Existing Video

Step 1 — Select Your Base Video

Upload the video you want to extend. This can be a video you previously generated with Seedance 2.0, or it can be an externally sourced video. The model accepts video files up to 15 seconds in length. If your base video is longer, select the portion whose ending you want to continue from. The model will analyze the full uploaded clip to understand context, then generate a continuation from the final moments.

Step 2 — Describe the Extension Direction

Your text prompt for the extension should describe what happens next, not what has already happened. Think of it as directing the next scene. Be specific about how the camera should continue moving, what new elements should enter the frame, and how the mood should evolve.

Example — Extending a Product Reveal:

"Continue from @Video1. The camera completes its orbit around the product and begins a slow push-in toward the brand logo on the front face. Lighting shifts from cool blue side-light to warm golden front-light as the camera approaches. The surface reflections intensify as we get closer. Duration: 10 seconds."

Example — Extending a Landscape Scene:

"Continue from @Video1. The camera continues its upward crane movement, rising above the treeline to reveal the mountain range and valley below. Morning fog drifts through the valleys. The sun crests the peak as the camera reaches its highest point. A hawk enters the frame from the right. Duration: 12 seconds."

Example — Extending a Fashion Sequence:

"Continue from @Video1. After the whip pan transition, the camera settles on the second outfit — a structured blazer over a silk camisole. The model turns slowly, and the camera tracks in a smooth semi-circle from a three-quarter angle to profile. Soft studio lighting with gentle shadows. Duration: 15 seconds."

Step 3 — Configure and Generate

Select your extension duration. For smooth continuity, the extension should use the same aspect ratio as the original video. Generate and review. If the extension doesn't flow seamlessly — perhaps the lighting shifts too abruptly or the camera trajectory diverges — adjust your prompt to be more explicit about maintaining specific elements. "Maintain the exact same lighting angle and color temperature from the original" is a helpful directive.

Step 4 — Chain Multiple Extensions

For longer narratives, chain extensions sequentially. Take the output from Step 3 and use it as the input for the next extension. Each chain link adds another segment to the total duration. A typical workflow might look like this:

Result: a 45-second continuous video with evolving camera work and narrative progression, all generated from AI with seamless transitions between each segment.

Video Editing: Modify Without Rebuilding

Video editing in Seedance 2.0 operates on a different principle than extension. Instead of adding time, you're modifying content within the existing timeline. The model supports three primary editing operations: character replacement, element deletion, and element addition.

Character Replacement

Upload the existing video and a reference image of the new character (or product, or object) you want to substitute. The model replaces the specified element while maintaining everything else — background, lighting, camera movement, timing, and all other elements in the scene.

Example prompt:

"In @Video1, replace the red handbag with @Image1 (a black leather briefcase). Keep the same hand movements, camera angle, lighting, and background. The briefcase should match the same scale and position as the original handbag throughout the entire video."

This is extraordinarily useful for product variants. Generate one hero commercial, then swap the product for each SKU in your line — different colors, different models, limited editions — without regenerating the entire video each time.

Element Deletion

Remove an object, a background element, or a visual distraction from an existing video. The model fills in the removed area with contextually appropriate content, maintaining the background and visual flow.

Example prompt:

"In @Video1, remove the coffee cup from the desk on the left side of the frame. Fill the area with a continuation of the desk surface. Keep everything else unchanged — the lighting, the other objects, the camera movement."

Element Addition

Add new objects, characters, or visual elements to an existing video. Upload reference images for the new elements and describe their placement, behavior, and integration with the existing scene.

Example prompt:

"In @Video1, add @Image1 (a small potted succulent) to the right side of the desk, near the monitor. It should be stationary and lit consistently with the existing scene lighting. It should remain in frame as the camera pans. Everything else unchanged."

Real-World Workflows for Extension and Editing

Building Long-Form Product Stories

Start with a 15-second product reveal. Extend it with a usage scenario. Extend again with a detail showcase. Extend once more with a brand lifestyle moment. In four generations, you have a 60-second product story that flows continuously, built iteratively rather than trying to nail everything in a single generation.

Product Line Variations

Generate one commercial with your flagship product. Use video editing to swap the product for each variant — different colors, sizes, configurations. Five product variants from one commercial generation, each maintaining the exact same camera work, lighting, and production quality. This is how you scale video production across a product catalog.

Fixing Imperfect Generations

Generated a video that's 90% perfect but has a distracting element in one corner? Use element deletion to remove it rather than regenerating from scratch and losing everything that worked. Generated a product video where the background is slightly wrong? Edit the background element without touching the product. This selective editing means you never lose a good generation to a minor imperfection.

Iterative Storyboarding

For creative projects, use extension as a storyboarding tool. Generate scene one, review it, then extend with scene two based on what scene one established. Each extension builds on the visual foundation of the previous segment, and you can adjust the narrative direction as you go. This iterative approach produces more coherent and intentional long-form content than trying to plan everything upfront.

Social Media Content Series

Generate a base video and then create multiple edited versions for different platforms. The base version for YouTube at 16:9. An edited version with additional text overlays for Instagram. A trimmed, punchy version for TikTok. Each version starts from the same successful generation and is modified for its destination platform.

Advanced Techniques

Progressive Scene Building: Rather than generating an entire complex scene in one shot, build it progressively. Generate a basic scene first, then use element addition to place objects and characters one at a time. Each addition is more controlled than trying to specify everything in a single generation prompt.

Style Evolution Through Extension: Use extensions to create deliberate style shifts within a video. The first segment might be bright and colorful. The extension prompt can introduce a mood shift — "the lighting gradually transitions from warm daylight to cool blue twilight as the camera pushes forward." The model handles the transition smoothly because it's working from the existing visual context.

Reference-Guided Extension: When extending, you can include reference videos alongside your base video. "Continue from @Video1. Use @Video2 as a reference for the camera movement in this extension — replicate the spiral descent from @Video2 while continuing the scene from @Video1." This lets you change camera techniques mid-sequence, creating complex choreography through iterative generation.

A/B Version Creation: Generate a base video, then extend it in two different directions. One extension takes the scene toward a dramatic reveal. Another takes it toward a subtle, atmospheric conclusion. Same starting point, different creative directions, each available as a complete video. This is invaluable for testing different narrative approaches without committing to a single direction upfront.

Pro Tips for Extension and Editing

The ability to extend and edit video iteratively transforms AI video from a slot machine — pull the lever, hope for the best — into a genuine creative tool. You build, you review, you refine. Each generation step makes the output closer to your vision. That's how real production works, and Seedance 2.0 is the first AI video model that truly supports it.

Start experimenting with extension and editing workflows in Seedance 2.0 — access it through Agent Opus and bring the iterative creative process to your AI video production.

Frequently Asked Questions

Can I extend a video that wasn't originally created with Seedance 2.0?

Yes. Seedance 2.0's video extension feature works with any video input, not just videos generated by the model itself. You can upload footage from your phone, clips from a DSLR, screen recordings, or videos from other AI generators. The model analyzes the uploaded video's visual properties — style, lighting, camera movement trajectory, subject appearance — and generates a continuation that matches. The key constraint is the 15-second maximum input length. If your source video is longer, select the segment whose ending you want to continue from, trim it to 15 seconds or less, and upload that as your base.

How many times can I chain extensions together? Is there a limit?

There is no hard limit on the number of extensions you can chain. Each extension adds 4 to 15 seconds of new footage. Practically, you can build videos that are several minutes long by chaining multiple extensions. However, be aware that visual consistency may gradually drift over very long chains — the 20th extension might not perfectly match the style of the first generation. To mitigate this, include explicit continuity instructions in each extension prompt, and periodically reference the original generation's visual properties. For most use cases, 3 to 6 extensions (producing 30-90 seconds of total footage) maintain excellent consistency.

When I edit a video to replace a character or object, does the rest of the video stay exactly the same?

The model works to preserve everything outside the edited element as closely as possible. Camera movement, lighting, background, timing, and all non-edited objects remain consistent. In practice, extremely minor differences might appear in areas immediately adjacent to the edit — similar to how content-aware fill in Photoshop might slightly adjust pixels near the edit boundary. However, for the vast majority of the frame, the video remains identical. The quality of the preservation depends on how clearly you specify what should change and what should stay the same in your prompt. Be explicit: "Replace only the handbag. Keep all camera movement, lighting, background elements, and hand positions exactly as they are."

Can I use video extension to create seamless looping videos for websites?

Yes, and this is an excellent use case. To create a seamless loop, generate your base video, then extend it with a prompt that directs the scene back toward its starting composition. For example, if your base video features a slow orbital camera movement around a product, extend it by directing the orbit to complete a full 360 degrees, ending at the same angle where it started. The key phrase to include in your prompt is: "The final frame should match the composition, lighting, and camera angle of the first frame of the original video to create a seamless loop." You may need to do minor trimming at the edit point, but Seedance 2.0's temporal coherence makes near-seamless loops achievable in one or two attempts.