Apple's STARFlow2 unifies text-image generation with normalizing flows

STARFlow2, built on the Pretzel architecture, interleaves a frozen VLM with a TARFlow stream via residual skip connections, enabling continuous, single-pass, causal multimodal generation. It supports cache-friendly interleaved generation where text and visual outputs enter the KV-cache without re-encoding, showing strong performance on image generation and understanding benchmarks.