Next Block Prediction: Video Generation via Semi-Autoregressive Modeling
Authors: name: Shuhuai Ren, name: Shuming Ma, name: Xu Sun, name: Furu Wei

Next-Token Prediction (NTP) is a de facto approach for autoregressive (AR)
video generation, but it suffers from suboptimal unidirectional dependencies
and slow inference speed. In this work, we propose a semi-autoregressive
(semi-AR) framework, called Next-Block Prediction (NBP), for video generation.
By uniformly decomposing video content into equal-sized blocks (e.g., rows or
frames), we shift the generation unit from individual tokens to blocks,
allowing each token in the current block to simultaneously predict the
corresponding token in the next block. Unlike traditional AR modeling, our
framework employs bidirectional attention within each block, enabling tokens to
capture more robust spatial dependencies. By predicting multiple tokens in
parallel, NBP models significantly reduce the number of generation steps,
leading to faster and more efficient inference. Our model achieves FVD scores
of 103.3 on UCF101 and 25.5 on K600, outperforming the vanilla NTP model by an
average of 4.4. Furthermore, thanks to the reduced number of inference steps,
the NBP model generates 8.89 frames (128x128 resolution) per second, achieving
an 11x speedup. We also explored model scales ranging from 700M to 3B
parameters, observing significant improvements in generation quality, with FVD
scores dropping from 103.3 to 55.3 on UCF101 and from 25.5 to 19.5 on K600,
demonstrating the scalability of our approach.