Evolution of NVENC Efficiency: A Longitudinal Analysis of HQ and UHQ Tuning Efficiency, Latency and Energy Trade-offs

TL;DR

This paper analyzes the evolution of NVIDIA NVENC hardware encoding, highlighting efficiency gains and the significant latency and energy trade-offs of the new UHQ mode, which limits real-time use but benefits VoD transcoding.

Contribution

It provides a comprehensive longitudinal analysis of NVENC from Pascal to Blackwell, revealing efficiency improvements and the impact of UHQ mode on latency and power consumption.

Findings

Blackwell architecture achieves up to 22.79% BD-Rate gain in UHQ mode.

UHQ mode increases latency by over 400% and power consumption by up to 40%.

UHQ mode is unsuitable for real-time applications but effective for VoD transcoding.

Abstract

The rapid expansion of uplink-intensive applications necessitates video coding solutions that balance high Rate-Distortion (RD) efficiency with ultra-low latency. This paper presents a longitudinal performance analysis of NVIDIA hardware encoding (NVENC), spanning from Pascal to the emerging Blackwell generation. We specifically evaluate the operational viability of the new "Ultra High Quality" (UHQ) tuning mode against standard low-latency configurations. Our results demonstrate that while the Blackwell architecture breaks historical efficiency plateaus, achieving a 5.94% BD-Rate gain in standard modes and up to 22.79% in UHQ modes, these gains incur severe system-level penalties. We reveal that UHQ operates as a hybrid pipeline, offloading complexity to CUDA cores and enforcing aggressive temporal structures (up to 7 B-frames) that increase end-to-end latency by over 400% and GPU board power consumption by up to 40%. Consequently, while UHQ successfully bridges the quality gap with software encoders, its prohibitive serialization delay renders it unsuitable for interactive real-time communications, positioning it instead as a specialized solution for Video-on-Demand (VoD) transcoding.