Four Bits, One Identity Crisis: What W4A4 Video Quantization Actually Breaks
TL;DR for operators The useful surprise in Tail-Aware HiFloat4 is not that a 4-bit video model gets worse. That part is not exactly a Nobel-level plot twist. The useful surprise is where it gets worse. The paper reports a W4A4 HiFloat4 post-training quantization pipeline for Wan2.2-I2V-A14B, and under matched generation settings the unweighted mean score drops from 0.6800 to 0.5880. But the collapse is concentrated: subject consistency falls from 0.9331 to 0.5324, while aesthetic quality is effectively unchanged, overall consistency is comparable, and motion smoothness drops only slightly from 0.9923 to 0.9803.1 ...