BytePlus Seedance 2.5 multimodal video generation, the next generation after Seedance 2.0 with long-form storytelling, omni references, and controllable editing. Inputs are greatly expanded: up to 50 reference assets per request (up to 30 images, 10 reference videos, and 10 audio clips). Freely combine text, images, videos, and audio to generate a video, edit a reference video (add or remove objects, replace the subject), or extend it forward or backward. The control panel offers an aspect-ratio selector with 7 options: 16:9 (landscape, YouTube), 9:16 (portrait, IG Reels / TikTok), 1:1 (square, IG posts), 4:3, 3:4, 21:9 (ultrawide cinematic), and adaptive (follows the reference assets). Upload a first-frame image to set the opening shot and a last-frame image to set the ending shot; upload multiple keyframe images to chain scenes in order. When a first/last frame is uploaded, the aspect ratio automatically follows the image. Refer to assets in the prompt as @Image 1, @Video 1, and @Audio 1 to assign their roles. Dialogue generation natively supports more than 10 languages including Chinese, English, Japanese, and Korean - great for product ads, story shorts, music videos, and multilingual marketing clips. The result downloads as an MP4 file. Usage: 1. Prompt only, no file uploads. 2. Prompt + first-frame image (optionally + last-frame image). 3. Prompt + keyframe images. 4. Prompt + reference images / videos / audio clips (assign roles with @Image 1, @Video 1, @Audio 1). Do not upload first-frame, last-frame, and keyframe images at the same time. Generated videos are 15 seconds long at 720P; the aspect ratio follows the control-panel selection (default 16:9). With a first/last frame or a reference video the aspect ratio follows the asset automatically, and with a reference video the model decides the video length (up to 30 seconds). Maximum total upload size per request: 256MB (all files and message content combined). Accepted image formats: bmp, gif, heic, heif, jpeg, jpg, png, tif, tiff, webp. Maximum number of images: 30. Maximum size per image: 30MB. Image dimensions: 300 to 6,000 pixels per side. Accepted video formats: mov, mp4. Maximum number of videos: 10. Maximum size per video: 200MB. Video duration: 2 to 30 seconds (total at most 30 seconds). Video dimensions: 300 to 6,000 pixels per side. Video resolution: 407,696 to 8,295,044 pixels in total. Video aspect ratio: 0.4 to 2.5. Video frame rate: 24 to 60 fps. Accepted audio formats: mp3, wav. Maximum number of audio files: 10. Maximum size per audio file: 15MB. Audio duration: 2 to 30 seconds (total at most 30 seconds). Output content formats: Video Video output: one 15-second 720P MP4 video; the aspect ratio follows the panel selection (with a reference video the model decides the aspect ratio and length automatically, up to 30 seconds). This module does not support continuous conversations.