oa::ResidualVqResult

residual Vector quantizer (RVQ) Stacks Q VectorQuantizer levels: level 0 quantizes z_e, level q quantizes the residual left by levels 0..q-1. The quantized output is the SUM of all levels' codes, so Q tokens per frame give far finer reconstruction than one (K^Q effective codes) — the basis for MoMask / MotionDreamer residual-token generation, where a masked model later predicts these per-level tokens. Each level keeps its own EMA codebook; the straight-through estimate and commitment loss apply once on the total.