FrameTrace: frame-level telemetry for media over QUIC

Live-streaming and remote control applications increasingly demand low end-to-end latency. Yet, evaluation tools of today give only connection-level or segment-level metrics. Coarse telemetry obscures the distinction between stalls experienced during encoding, propagation, and rendering, thereby concealing system bottlenecks. For example, under lossy conditions, long Group-of-Pictures (GoP) sizes increase stall duration as delayed I-frames block decoding of dependent frames. Prior studies of Media over QUIC (MoQ) use average segment times or logs from video players, leaving the frame-level latency and quality trade-off largely unexplored. In this paper, we introduce FrameTrace, a frame-level logger for analyzing Quality of Experience telemetry. Using FrameTrace, we demonstrate that MoQ itself cuts latency by 83% and 63% at 5% packet loss and 10 Mbps bandwidth limitation, respectively, compared to Low-Latency DASH (LL-DASH). As a case study, we investigate how dynamically adapting GoP size changes stall duration and perceived quality. A shorter GoP size improves the VMAF score by up to 30% compared to a longer one. Driven by FrameTrace, our lightweight real-time GoP adaptation controller reduces latency by an additional 10% while increasing VMAF by 3.65%.