Bytedance Seedance: a tool that supports multimodal input and generates video with native audio

Bytedance Seedance is an online authoring platform dedicated to running ByteDance's flagship video model, Seedance 2.0. Seedance 2.0 utilizes the Double Branch Diffusion Transformer (DB-DiT) architecture, which breaks through the limitations of traditional step-by-step generation of AI videos, and is able to output high-quality film and TV-grade footage and precisely synchronized original audio (including music, sound effects, and lip-synced dialog) simultaneously in a single generation process. It can simultaneously output high-quality film and television-quality images and accurately synchronized original audio (including music, sound effects, and lip-synchronized dialogue) in a single generation process. The platform supports a rich set of multimodal inputs, allowing users to mix text cues, up to 9 reference images, 3 reference videos, and 3 audio tracks to accurately control character consistency, screen style, and camera movement. Whether starting from scratch with text-to-graphic or graphic-to-graphic video, or utilizing Fast Video-Edit to rewrite the lighting, weather, or specified elements of the original video using only natural language commands (with perfect preservation of the original motion and composition), Bytedance Seedance provides creators with a highly efficient and professional production experience of up to 15 seconds at 2K resolution.

Function List

• Native audio and video generation in a single passThe parallel stream processing architecture is used to produce matching background music, ambient sound effects and lip-synchronized dialogues directly while generating the screen, eliminating the need for third-party post-production dubbing.
• Extreme multimodal mix-and-match input: Upload up to 9 style/character reference images, 3 reference videos and 3 audio clips in a single task to perfectly target the desired character image or visual style.
• First and last frame animation control (graphic video)Support to specify the image as the start frame and end frame of the video, the system automatically calculates the reasonable physical motion and physical coherent transitions.
• Fast Video-Edit (Fast Video-Edit)No need to mask keying, directly input the original video and natural language, you can quickly reconstruct the lighting, weather or specific elements of the picture, while retaining the original character identity, movement trajectory and picture composition without loss.
• Director-level professional shot controlThe built-in advanced lens parameters support cinematic effects such as Dolly Zoom, Rack Focus, POV, handheld camera shake, and tracking.
• High specification output with adaptive parametersIt supports resolutions from 480p to 2K UHD, covers all major screen aspect ratios (16:9, 9:16, 1:1, etc.), and supports flexible adjustment of video duration from 4 to 15 seconds.

Using Help

Bytedance Seedance is a cloud-based web-based online video generation platform that requires no client download. The platform is equipped with the latest Seedance 2.0 model, which allows you to create movie-quality video and audio by simply accessing the URL through your browser. In order to maximize the power of the platform, the following is a detailed procedure and user guide:

I. Account Registration and Workbench Initialization

1. Access & Login: Use your browser to open the official website https://www.bytedanceseedance.com and click the “Sign Up/Login” button at the top right corner of the page. The platform supports one-click authorization to log in using email or common third-party accounts, which is convenient and fast.
2. Access to the Creation DeskAfter logging in successfully, click “Start Creating” to enter the workbench. The workbench interface is intuitively distributed, mainly divided into three core areas: the left side of the [multimodal input area] (including text input box, image, video, audio upload module), the center of the [parameters and mirror settings area], and the right side of the [real-time preview and generation history area].

Core Function 1: Text to Video and Image to Video (Text/Image to Video)

Use this feature as a priority if you want to build a brand new video scene from scratch.

1. Fill in the Prompt: In the text box on the left, describe your desired image in detail and in natural language. For best results, it is recommended to use a structured formula of cue words, e.g. “Description of subject + Specific action + Setting environment + Lighting atmosphere + Medium/style of shooting”.
2. Add Image Reference：
   • If you need extremely precise control of the drawing style or to maintain consistency of character features, click on the image upload button. System Single GenerationSupports uploading up to 9 reference images, you can upload multiple photos of the same character to lock the IP image.
   • Precise control of the first and last framesIn Graphic Video mode, you can specify the first image as the “Start Frame” and the last image as the “End Frame”. The model will automatically complement the physical movement and transitions between the two, allowing the static image to move as you envisioned.
3. Setting the base parameters：
   • video resolution: 480p, 720p (recommended by default for speed and quality), 1080p to up to 2K resolution options.
   • aspect ratio: Choose the right size according to your posting platform, such as 16:9 (horizontal screen/B station/YouTube), 9:16 (vertical screen/Jitterbug/Reels), 1:1 (Circle of Friends/Instagram) or 21:9 (Movie Wide).
   • generation time: The slider can be adjusted by freely dragging it between 4 and 15 seconds.

Core Function 2: Fast Video-Edit (Fast Video Redraw)

This is the most efficient and least costly tool to use when you already have a video on hand, but want to change the weather, environment, character costumes, or even the overall painting style in it.

1. Upload source videoSelect “Video-to-Video” mode on the left side and upload the basic video clip you have prepared (if the original video is more than 15 seconds, the system will automatically capture the first 15 seconds as the processing object).
2. Enter the modification command: In the cue word box, there is no need to repeat the description of what is already in the original video, simplyDirectly describe the part you want to change.. For example, enter the command, “Change the scene from daytime to a cyberpunk style nighttime rainy day with the characters wearing mechs”.
3. Fully automatic non-destructive replacementThe model is different from traditional video post-production in that it does not require you to perform frame-by-frame masking, keying, or green-screen operations. The model will accurately identify and redraw the target pixels while keeping the original video's camera track, character movement and composition completely unchanged, which greatly improves productivity.

Core Function 3: Native Audio Sync

The biggest breakthrough of Seedance 2.0 is the simultaneous generation of audio and video, eliminating the need to switch to third-party audio software for dubbing.

1. Automatic Audio Generation: Check “Enable Audio” in the parameter panel. When you click Generate, the system will analyze the video content and automatically match the background music (BGM) and ambient sound effects (SFX), such as wind, car engine or footsteps, in the same generated channel.
2. Specify audio reference: If you have specific requirements for the soundtrack, you can upload theUp to 3 audio filesAs an emotional or rhythmic reference, the model will generate images that fit the ambience of that melody.
3. Lip-syncIf you enter a specific line text or upload a pure voice dialogue audio, the system will automatically recognize the facial features of the person pronouncing the line in the screen and generate a high-definition video clip that perfectly matches the pronunciation and mouth shape of the line.

V. Advanced operations: director-level camera control (Camera Control)

For a professional, cinematic look and feel to the resulting video, you can make precise adjustments with the center lens control panel.

1. Basic Lens Motion: Precisely control the speed and direction of Pan, Tilt, Roll and Zoom with sliders.
2. Advanced Movie Lens Effects：
   • Dolly Zoom: Turn on this item to realize the famous “Hitchcock Zoom” style of spatial distortion of the visual sense, that is, the subject of the figure remains the same size, while the background produces a sharp stretch or compression.
   • Rack Focus: You can set up timestamps to subtly guide the viewer's eye by smoothly shifting the focus from the foreground characters to the background scenery as the video plays.
   • Perspective switching and handheld sensationThe “POV Switch” option simulates a first-person subjective perspective; checking the “Handheld Movement” option adds a slight physical breathlessness to the image, enhancing the sense of realism and immersion. The

VI. Generation and export

Once all the parameters have been set, click on the “Generate” button at the bottom. Thanks to the DB-DiT parallel computing architecture, the system can produce both video and audio in a short time. Once generated, the media file will be displayed in the “History” column on the right. You can click the Play button to preview the file in real-time online, and then click “Download” to save the complete MP4 HD file with native sound effects to your local device for subsequent distribution or direct commercial use.

application scenario

1. Film and Video Scripting and Short Film Production
   Indie directors and film crews can use the text and reference images to quickly generate split-screen preview videos with precise camera movements and native soundtracks, or directly create conceptual movie shorts, dramatically reducing the cost of pre-production.
2. Advertising marketing and e-commerce material generation
   With Fast Video-Edit, merchants only need to shoot a basic video of a product, and can replace the background of different seasons, festivals or usage environments with natural language commands in a single click, producing multiple versions of marketing materials in batch and realizing cost reduction and efficiency.
3. Self-Publishing & Social Media Content Creation
   Short video creators only need to input the script, and then the platform can simultaneously generate images, background music and a digital narrator with precise mouth synchronization, eliminating the need for separate recording and editing and realizing one-stop content realization.
4. Game Asset Presentation and Concept Development
   Game developers can upload multi-angle 2D character design drawings and reference action videos to generate 3D-level dynamic performance and physical feedback of the character in specific environments through the multi-modal input function, which can be used for the production of the game's promotional PV.

QA

1. What are the limits on the resolution and duration of videos generated by the platform?
   The platform currently supports the output of HD video from 480p to the highest 2K resolution, can be adapted to 16:9, 9:16 and other types of aspect ratios, and the duration of a single generation of video can be set between 4 and 15 seconds.
2. Is it necessary to use additional audio software to dub the generated video?
   No need at all. The platform adopts the audio and video parallel stream generation architecture, which will directly produce matching native background music, ambient sound effects and even lip-synchronized dialogue audio while generating the screen, completing the audio-visual work in one go.
3. What is the difference between Fast Video-Edit (video editing) and the standard video generation mode? What are the fees?
   Fast Video-Edit is mainly used to quickly redraw the light, shadow, environment and elements of the existing video, while it will perfectly preserve the character movement and frame composition of the original video without masking. Compared with the standard video generation mode, this function can save about 19% computing cost, which is ideal for high-frequency iteration and modification of video.
4. How do you ensure coherent and consistent characterization in the generated video?
   The platform supports extremely powerful multimodal input controls. You can upload up to 9 reference images simultaneously in a single task. By providing photos of your characters in different angles and expressions, you can firmly lock down the IP attributes of your characters and ensure a high degree of consistency of character traits in your videos.