Volcano Engine releases Doubao Large Model 1.8 and Seedance 1.5 pro

Background

Volcano Engine is the cloud arm of ByteDance. Its FORCE conference on 18 December 2025 was the setting for two model releases: Doubao Large Model 1.8 and the audio-video generation model Seedance 1.5 pro.^[1]

Video understanding means that a model can analyse what happens in a clip, including objects, actions and the order of events. The number of frames a model can take in one pass sets how much of a video it sees at once, so raising that number lets it take in more footage without splitting the clip.

Pay-as-you-go pricing charges according to how much a customer uses, rather than a fixed subscription fee. Tiered discounts reduce the unit price once usage passes set levels.

Tool calling means that a model can decide to call an external function, such as a search, a calculator or a software interface, and then use the result in its answer. An OS agent works on a computer's operating system: it observes the screen, moves the pointer and types, which allows it to complete tasks inside ordinary applications.

What happened

Doubao 1.8 was optimised for multimodal agent tasks, with stronger tool calling, instruction following and OS-agent abilities.^[1] Its single-pass video understanding capacity doubled from 640 to 1,280 frames.^[1] The launch was accompanied by Seedance 1.5 pro, which generates sound and picture jointly with millisecond-level audio-video sync.^[1]

Key details

Volcano Engine also introduced AgentKit and HiAgent Workbench, which are agent tools, and an AI savings plan. The plan offers tiered discounts of up to 47% on pay-as-you-go model usage.^[1][2]

At the event, Tan Dai, Volcano Engine's president, said daily token usage of Doubao models had passed 50 trillion. That was up more than tenfold year on year.^[1]

Impact

The release showed ByteDance putting its models into agent products and offering them to businesses through pay-as-you-go pricing with discounts. The growth figure Tan Dai gave was the company's own measure of how much the Doubao models were being used.