Masked Generative Nested Transformers with Decode Time Scaling
Sahil GoyalDebapriya TulaGagan JainPradeep ShenoyPrateek JainSujoy Paul
Presents a decode-time scaling framework for masked generative transformers that shares parameters across nested sub-models and reuses cached computations, reducing visual generation inference compute nearly threefold without sacrificing quality.
Visual generation models, such as diffusion and discrete masked transformers, generate high-quality images and videos but face severe inference bottlenecks. Standard parallel decoding algorithms repeatedly pass the entire model across all decoding iterations. Running a uniform, large model throughout the entire sequence causes substantial computational redundancy because initial generation stages primarily require coarse structuring rather than fine-grained refinement.
The article introduces Masked Generative Nested Transformers with Decode Time Scaling (MaGNeTS) to accelerate inference in visual generation. The authors evaluate whether dynamic model scaling paired with key-value caching across decoding iterations can significantly lower computational requirements without compromising generation quality.
The researchers designed an architecture that scales nested sub-models extracted from a single transformer backbone, sharing all parameters without increasing memory footprint. Generation starts using the smallest nested model and progressively switches to larger models as iterations proceed. The approach incorporates key-value caching to store and reuse representations of unmasked tokens across iterations, combined with periodic cache refreshes during model transitions to preserve accuracy. The framework was trained using progressive knowledge distillation alongside ground-truth losses and evaluated across standard visual benchmarks, including class-conditional ImageNet image generation, UCF101 video generation, and Kinetics600 frame prediction.
The experimental findings show substantial efficiency gains across all evaluated tasks. First, MaGNeTS reduces computational operations by 2.5 to 3.7 times compared to strong baselines, cutting ImageNet generation compute by approximately 3x (from 1,800 to 608 GFLOPs in a 16-step setup) while maintaining competitive image quality. Second, on hardware evaluations using a single accelerator chip, real-time throughput increased by 2.5 times, rising from 22.5 to 56.3 images per second. Third, scaling model sizes upward from small to large outperformed reverse or static schedules, confirming that larger capacity is strictly necessary only in final refinement steps. Fourth, while basic caching degraded output quality, periodic cache refreshes during model transitions restored generation fidelity while retaining major computational savings.
These results demonstrate that uniform compute allocation across iterative generation is inefficient. By front-loading computation onto smaller nested structures and caching static tokens, organizations can drastically reduce infrastructure costs, operational energy consumption, and user-facing latency in generative media pipelines. The framework achieves state-of-the-art efficiency while avoiding the overhead of deploying separate, disjoint models for each stage.
Decision-makers should consider adopting dynamic compute schedules and nested architectures for parallel decoding workflows. Development teams can implement progressive model scaling schedules immediately on compatible masked architectures, while ensuring guidance mechanisms are applied only during final iterations to maximize efficiency. Future work should focus on investigating token-dependent dynamic schedules and optimizing cache-refresh mechanisms to eliminate remaining compute overheads.
The primary limitation of this method is its reliance on discrete token representations, meaning key-value caching cannot be directly transferred to continuous-space models without modification. Furthermore, overall visual fidelity remains dependent on the quality of underlying visual tokenizers, and baseline visual artifacts can persist in the output. Within the scope of discrete masked transformer generation, confidence in the reported computational savings and throughput improvements is high.
- Paper: Scalable Adaptive Computation for Iterative Generation, Allan Jabri et al. (2023). Its adaptive computation and reuse of latent context across iterative generation provide the key ideas behind allocating less compute to some generation steps and caching work.
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