Evaluation of GPU Video Encoder for Low-Latency Real-Time 4K UHD Encoding

TL;DR

This paper evaluates GPU hardware encoders for 4K UHD real-time streaming, demonstrating that Ultra Low-Latency modes significantly reduce end-to-end latency with minimal impact on quality, outperforming software encoders.

Contribution

It provides a comprehensive performance analysis of GPU hardware encoders' low-latency modes across major vendors, highlighting their advantages over software solutions.

Findings

Hardware encoders achieve lower latency than software encoders.

Ultra Low-Latency mode reduces latency to 83 ms without quality loss.

Latency is insensitive to quality presets, enabling high-quality low-latency streaming.

Abstract

The demand for high-quality, real-time video streaming has grown exponentially, with 4K Ultra High Definition (UHD) becoming the new standard for many applications such as live broadcasting, TV services, and interactive cloud gaming. This trend has driven the integration of dedicated hardware encoders into modern Graphics Processing Units (GPUs). Nowadays, these encoders support advanced codecs like HEVC and AV1 and feature specialized Low-Latency and Ultra Low-Latency tuning, targeting end-to-end latencies of < 2 seconds and < 500 ms, respectively. As the demand for such capabilities grows toward the 6G era, a clear understanding of their performance implications is essential. In this work, we evaluate the low-latency encoding modes on GPUs from NVIDIA, Intel, and AMD from both Rate-Distortion (RD) performance and latency perspectives. The results are then compared against both the normal-latency tuning of hardware encoders and leading software encoders. Results show hardware encoders achieve significantly lower E2E latency than software solutions with slightly better RD performance. While standard Low-Latency tuning yields a poor quality-latency trade-off, the Ultra Low-Latency mode reduces E2E latency to 83 ms (5 frames) without additional RD impact. Furthermore, hardware encoder latency is largely insensitive to quality presets, enabling high-quality, low-latency streams without compromise.