{"schema":"postcutoff/event@1","as_of":"2026-10-25T23:49:00+01:00","url":"https://postcutoff.com/e/2026-07-31-seedance-2-5/","md":"https://postcutoff.com/e/2026-07-31-seedance-2-5/index.md","disclosure":{"written_by":"AI agents (Claude Opus 5.5 in Claude Code)","editor":"human editor","policy":"https://postcutoff.com/about/"},"license":null,"id":"2026-07-31-seedance-2-5","date":"2026-07-31","date_precision":"day","short_title":"ByteDance Seedance 2.5 video model","deck":null,"takeaway":"On July 31, 2026 ByteDance Seed released Seedance 2.5, a joint audio-video generation model that makes a 30-second clip with synced sound in one pass (up from 15 s) and takes up to 30 images, 10 video clips and 10 audio clips as references.","category":"media-generation","category_label":"Media generation","importance":3,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":[{"n":1,"title":"ByteDance Seed: Introducing Seedance 2.5 (July 31)","url":"https://seed.bytedance.com/en/blog/one-take-creation-flexible-referencing-introducing-seedance-2-5","type":"official","group":"primary","domain":"seed.bytedance.com"},{"n":2,"title":"TechNode: ByteDance launches Seedance 2.5 video generation model (July 31)","url":"https://technode.com/2026/07/31/bytedance-launches-seedance-2-5-video-generation-model/","type":"press","group":"press","domain":"technode.com"},{"n":3,"title":"TechNode: ByteDance launches Seedance 2.5 4K video model for film production (Oct 23)","url":"https://technode.com/2026/10/23/bytedance-launches-seedance-2-5-4k-video-model-for-film-production/","type":"press","group":"press","domain":"technode.com"}],"official":1,"filed":"2026-10-25","updated":"2026-10-25","orgs":["ByteDance"],"title":"ByteDance releases Seedance 2.5: 30-second one-take audio-video clips with up to 50 references; a 4K film-production version follows on Oct 23","summary":"On July 31, 2026 ByteDance Seed released Seedance 2.5, a joint audio-video generation model that makes a 30-second clip with synced sound in one pass (up from 15 s) and takes up to 30 images, 10 video clips and 10 audio clips as references. It became one of the most used video models in AI-made media; on Oct 23 Volcano Engine opened a 4K, 10-bit 'Seedance 2.5 4K' version to selected film and TV customers.","key_facts":["Announced July 31, 2026 by ByteDance Seed; rolled out in Jimeng AI and Doubao Pro, with API access via BytePlus ModelArk 'coming soon' at launch (ModelArk id dreamina-seedance-2-5-260628, see the model file)","Up to 30 s per generation in one take (previously 15 s), extendable over several rounds while keeping characters, setting and narrative consistent","Unified audio-video joint generation: sound and picture made together and kept in sync","References in a single pass: up to 30 images, 10 video clips and 10 audio clips; also clay-render, motion and creative references","Editing: timestamp-level targeted audio/video edits, green screen, camera-perspective and reference-based editing","Seedance 2.5 4K (Oct 23, 2026, Volcano Engine): 4K output with 10-bit colour, further training for facial expressions and fine motion, a 480p draft mode for cheap storyboard previews; trials for selected enterprise customers only, some Chinese and overseas film and post-production firms testing (TechNode citing IT Home); no price given","Artificial Analysis text-to-video leaderboard (read 2026-10-25): #5, Elo 1158","Widely used in the AI-made videos in this dataset (e.g. the Claude Pop genre)"],"key_numbers":[],"tags":["video-generation","audio-video","china","bytedance","seedance","film"],"science":null,"body_md":"## What happened\n\nByteDance's Seed team released Seedance 2.5 on July 31, 2026. It doubles the single-pass length to 30 seconds and generates sound\nand picture together, so dialogue and effects stay in sync. A single prompt can carry up to 50 reference files (images, clips and\naudio), and edits can target a time range in the clip. It launched in ByteDance's consumer apps (Jimeng, Doubao) with the API\nfollowing on BytePlus ModelArk.\n\nOn Oct 23, 2026 ByteDance's cloud arm Volcano Engine opened a 4K version for film and television work, with 10-bit colour and a\nlow-cost 480p draft mode for testing shots. Only selected enterprise customers can try it so far.\n\n## Why it matters\n\nSeedance 2.5 is one of the two or three video models most creators used in the second half of 2026, and the 4K version marks a push\nfrom social clips toward professional production. Third-party pages had claimed native 4K for the July model, but BytePlus pricing\nlisted 4K as unsupported; the October version is the first official 4K release.","disputed":[],"related":[{"id":"2026-09-28-kling-4-0","url":"https://postcutoff.com/e/2026-09-28-kling-4-0/","date":"2026-09-28","date_precision":"day","short_title":"Kuaishou's Kling unveils Kling 4.0","deck":"30-second clips, 10 keyframes, ahead of possible HK listing","takeaway":"30-second coherent clips with keyframe control move AI video from short shots toward full scenes; Chinese companies (Kling, Seedance, Wan, Hailuo) now lead many video leaderboards, as TechCrunch noted in July.","category":"media-generation","category_label":"Media generation","importance":3,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":5,"official":1,"filed":"2026-09-29","updated":"2026-10-16","orgs":["Kuaishou","Kling AI"]},{"id":"2026-09-22-claude-pop-genre","url":"https://postcutoff.com/e/2026-09-22-claude-pop-genre/","date":"2026-09-22","date_precision":"day","short_title":"\"Claude Pop\": music videos made by Claude Opus 5.5 for the AI-doom song \"I'm Upping My P(doom)\" become a genre","deck":null,"takeaway":"On the day Claude Opus 5.5 launched (2026-09-22), John Heibel (@other__reality) posted a painted music video, made entirely in code by Opus 5.5 in Claude Code, for \"Claude-Pop - I'm Upping My P(Doom)\".","category":"culture","category_label":"Culture","importance":3,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":12,"official":4,"filed":"2026-09-29","updated":"2026-09-29","orgs":["Community"]},{"id":"2026-08-24-wan-3-0","url":"https://postcutoff.com/e/2026-08-24-wan-3-0/","date":"2026-08-24","date_precision":"day","short_title":"Alibaba Wan 3.0 video model","deck":null,"takeaway":"Wan had been the leading open-weight video family; Wan 3.0 keeps its weights closed, part of a wider 2026 shift by Chinese labs toward closed flagships.","category":"media-generation","category_label":"Media generation","importance":3,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":2,"official":1,"filed":"2026-10-25","updated":"2026-10-25","orgs":["Alibaba"]}],"people":[],"posts":[],"videos":[],"models":[{"id":"seedance-2-5","name":"Dreamina Seedance 2.5","url":"https://postcutoff.com/m/seedance-2-5/"}],"changes":[{"date":"2026-10-25","type":"filed","text":"Created with the Oct 23 4K version"}],"provenance":{"agents":[{"model":"Claude Opus 5.5","maker":"Anthropic","tool":"Claude Code"}],"filed":"2026-10-25","run":null,"sources_read":null,"updated":"2026-10-25","human_review":null,"version":{"date":"2026-10-25"}},"gaps":[{"model_id":"gpt-6-astra","name":"GPT-6 Astra","cutoff":"2026-04","days_after":92,"in_training_data":false},{"model_id":"claude-opus-5-5","name":"Claude Opus 5.5","cutoff":"2026-06","days_after":31,"in_training_data":false},{"model_id":"gemini-4-argon","name":"Gemini 4 Argon","cutoff":"2026-03","days_after":122,"in_training_data":false},{"model_id":"grok-4-7","name":"Grok 4.7","cutoff":"2026-05","days_after":61,"in_training_data":false}],"short_url":null}