Helios is an open-source, real-time long video generation model from PKU-YuanGroup, the team behind Open-Sora Plan. It is a 14B diffusion transformer that achieves minute-scale, high-quality video synthesis at 19.5 FPS on a single H100 GPU (about 10 FPS on a single Ascend NPU). The headline result is notable because Helios reaches this without relying on the conventional long-video anti-drifting strategies or standard video acceleration techniques that most real-time systems depend on. ## Minute-Scale Video Without Anti-Drifting Tricks Most long-video generators fight temporal drift with mechanisms like self-forcing, error banks, keyframe sampling, or inverted sampling. Helios generates minute-scale videos with high quality and strong coherence without any of these, simplifying the pipeline while maintaining consistency over long durations. This makes it a clean baseline for studying long-horizon video generation. ## Real-Time Speed Without Standard Acceleration Helios also forgoes the usual acceleration toolbox — no KV-cache, causal masking, sparse or linear attention, TinyVAE, progressive noise schedules, hidden-state caching, or quantization — yet still delivers 19.5 FPS end-to-end on a single H100, with some users reporting over 20 FPS on stronger hardware. Instead, the authors introduce optimizations that raise both training and inference throughput while cutting memory, enabling image-diffusion-scale batch sizes during training and fitting up to four 14B models within 80GB of GPU memory. ## Flexible Deployment and Low VRAM Despite its 14B scale, Helios is engineered for accessibility. Group Offloading brings VRAM usage down to roughly 6GB, and Context Parallelism enables multi-GPU inference with Ulysses, Ring, Unified, and Ulysses-Anything attention variants. Community tutorials demonstrate installation on consumer-grade PCs and even 4K video generation, broadening its reach beyond datacenter hardware. ## Broad Ecosystem Support Helios launched with day-0 integration across the generative video ecosystem: Diffusers, SGLang-Diffusion, vLLM-Omni, and Huawei Ascend-NPU, plus Cache-DiT acceleration support. It ships three model variants — Helios-Base (best quality with v-prediction and a custom HeliosScheduler), Helios-Mid, and Helios-Distilled — covering text-to-video, image-to-video, video-to-video, and interactive generation. A Gradio demo, technical report on arXiv, and HuggingFace/ModelScope collections round out the release. ## Assessment Helios is a strong open-source contribution to real-time long video generation, pairing a genuinely fast inference path with permissive Apache-2.0 licensing and unusually broad framework support. Its willingness to drop common anti-drifting and acceleration tricks makes it both a practical tool and a useful research reference. The main caveats are hardware-dependent performance — real-world FPS varies with CPU, memory, and driver versions — and the fact that H100-class throughput remains out of reach for most consumer setups, where VRAM optimizations trade speed for accessibility.