Bridging the Perception Gap: A Lightweight Coarse-to-Fine Architecture for Edge Audio Systems
Hengfan Zhang, Yueqian Lin, Hai Helen Li, Yiran Chen
TL;DR
The paper tackles the perceptual gap in edge audio understanding, where single-pass Audio-LLMs struggle with multi-step reasoning under tight resource and privacy constraints. It introduces CoFi-Agent, a coarse-to-fine, hybrid edge-cloud architecture that performs a fast local perception and conditionally triggers lightweight cloud-guided refinement using on-device tools like temporal re-listening and local ASR while keeping raw audio on-device. On MMAR (N=1,000), it raises accuracy from 27.20% to 53.60% and reduces unnecessary cloud offloading by gating about 62% of samples, demonstrating a favorable accuracy-latency trade-off. This approach demonstrates practical edge deployment viability by maximizing informational value from compact evidence while preserving acoustic privacy.
Abstract
Deploying Audio-Language Models (Audio-LLMs) on edge infrastructure exposes a persistent tension between perception depth and computational efficiency. Lightweight local models tend to produce passive perception - generic summaries that miss the subtle evidence required for multi-step audio reasoning - while indiscriminate cloud offloading incurs unacceptable latency, bandwidth cost, and privacy risk. We propose CoFi-Agent (Tool-Augmented Coarse-to-Fine Agent), a hybrid architecture targeting edge servers and gateways. It performs fast local perception and triggers conditional forensic refinement only when uncertainty is detected. CoFi-Agent runs an initial single-pass on a local 7B Audio-LLM, then a cloud controller gates difficult cases and issues lightweight plans for on-device tools such as temporal re-listening and local ASR. On the MMAR benchmark, CoFi-Agent improves accuracy from 27.20% to 53.60%, while achieving a better accuracy-efficiency trade-off than an always-on investigation pipeline. Overall, CoFi-Agent bridges the perception gap via tool-enabled, conditional edge-cloud collaboration under practical system constraints.
