One-Step Diffusion Refiner Cuts Latency Ninefold

A single diffusion step now matches the fidelity of multi‑step refiners while slashing inference time by roughly nine times. In practice the latency drops from dozens of seconds to a handful, reshaping what real‑time high‑resolution video generation can look like.

Before SoL‑Refiner, most pipelines generated a low‑resolution clip and then applied two or three denoising passes to reach 4K quality. Each additional diffusion step introduced a second sampling bottleneck, so the overall throughput was dominated by the refiner rather than the base generator.

The one‑step refiner cuts refinement latency from 57.461 seconds down to 6.447 seconds in the standard 2K setting, an 8.91× speedup over the three‑step LTX‑2.3 Refiner [1]. This reduction is achieved with a combined training recipe that includes high‑resolution continual learning, reinforcement‑learning post‑training, and a final distillation step.

Across three different base generators, the pipeline trims overall latency by 54.7 %, 71.1 % and 64.4 % respectively while also improving mean VBench and UniPercept scores compared with direct high‑resolution generation [1]. The aggressive single‑step denoising therefore delivers both speed and quality gains.

With only one refinement pass, SoL‑Refiner outperforms every evaluated external refiner on VBench AQ, IQ, AVG and UniPercept AVG under the same step budget [1]. Even methods like SEEDVR2 fall short despite having comparable computational budgets.

The reported numbers are tied to a 2K latency benchmark; scaling the approach to native 4K or beyond may expose new bottlenecks in memory bandwidth or model stability. Moreover, the reinforcement‑learning fine‑tuning stage adds engineering complexity that could limit adoption in resource‑constrained environments.

If these results hold across broader hardware stacks, production video generation services should replace multi‑step refinement modules with the one‑step SoL‑Refiner and re‑evaluate their throughput metrics on benchmarks such as VBench. The shift promises near‑real‑time 4K output without sacrificing perceptual quality.

References

1. SoL-Refiner: Speed-of-Light One-Step Refinement for High-Resolution Video