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Vidu S1: A Real-Time Interactive Video Generation Model
Vidu S1 addresses the gap between high-quality offline video generation and live visual interaction by making video synthesis respond continuously to spoken user instructions. The paper proposes a speech-guided streaming generation model, supported by TurboDiffusion and TurboServe, that can produce stable 540p video at up to 42 FPS on consumer GPUs. Its reported results on Vidu-StreamBench and HDTF suggest that real-time, open-ended, controllable video generation can move from a batch creation workflow toward interactive applications such as digital characters, live entertainment, and conversational visual agents.
Source: Vidu S1: A Real-Time Interactive Video Generation Model

Why This Matters
The paper begins from a practical limitation in current systems such as Sora, Veo, Wan, and Seedance: they mainly follow an offline, one-shot generation paradigm in which a user submits a prompt and waits for a completed video. This workflow can produce high-quality clips, but it does not let the user steer the content while generation is underway. Vidu S1 is motivated by use cases where visual content must respond immediately, including face-to-face communication, livestreaming, games, and interactive digital characters. The authors argue that demand for real-time interactive visual content scales differently from replayable offline video, because interactive sessions are consumed as live experiences rather than shared artifacts. This framing positions real-time interactive video generation as a distinct problem, not merely a faster version of offline text-to-video synthesis.

The Gap
The paper identifies four gaps that prevent existing video generation methods from meeting this interactive target. First, autoregressive generation alone does not guarantee interaction, because a model may generate sequentially while still taking all control inputs only before generation begins. Second, many prior approaches do not treat speech as a direct and explicit control signal for future video content, which makes natural spoken instruction difficult to use as the main interface. Third, long-horizon video generation suffers from accumulated errors that can cause drift, instability, blur, or visual collapse over time. Fourth, the authors emphasize that practical real-time generation requires not only a model architecture but also efficient inference kernels, scheduling, serving systems, and deployment infrastructure.

Vidu S1's Core Idea
Vidu S1 is presented as a model for continuous user interaction in which speech instructions can guide what the video should generate next at any moment. The paper’s central design goal is future control: the user’s voice input is not simply an initial prompt but a continuing signal that can alter subsequent actions and behavior of a digital character. The system supports custom images of real people, anime subjects, and pets, and it also allows different voice tones for personalized generation. The authors further claim that Vidu S1 supports infinite-length real-time generation by mitigating the error accumulation that typically degrades streaming video models. This combination of speech-guided control, personalized characters, and long-horizon stability defines the paper’s main technical objective.

How They Make It Practical
The method section describes a data preparation pipeline built to support controllable, temporally coherent character video generation. The authors collect livestream or talking-head videos to learn facial expressions, body movement, and lip synchronization, and they add film and television footage to improve generalization across shot angles, scenes, and visual styles. Raw videos are deduplicated, prefiltered for frame rate, resolution, audio-visual integrity, and synchronization, then segmented into single-shot clips of 3 to 60 seconds without cutting through speech. The filtering process combines expert models with an omni model for global semantic understanding, screening for subject consistency, frame cleanliness, visual quality, content safety, shot stability, and interactivity. Speech diarization separates onscreen, offscreen, and overlapping speech, while structured clip-level and speech-aware chunk-level captions provide temporally localized conditioning signals. On the deployment side, the paper states that TurboDiffusion and TurboServe enable 540p real-time output at up to 42 FPS on regular consumer GPUs.

Takeaway
The reported experiments evaluate Vidu S1 on Vidu-StreamBench and HDTF, where the authors claim leading performance while satisfying real-time inference requirements. The paper reports best scores of CSIM 0.9192, Sync-D 7.847, and DOVER 0.5660, indicating attention to identity consistency, audio-visual synchronization, and perceptual video quality. The contribution statement also emphasizes strong human preference results, though the excerpt does not provide additional numerical detail for those judgments. These results support the paper’s broader claim that speech-guided interaction, stable open-ended streaming, and efficient serving can coexist in a single video generation system. The implication is that future video models may be evaluated less as isolated clip generators and more as responsive visual systems that operate continuously under user control.
