利用Cosmos微服务大规模提高Netflix视频质量
by Christos G. Bampis, Chao Chen, Anush K. Moorthy and Zhi Li
藉由 Christos G. Bampis, 陈超, Anush K. Moorthy 和 李智
Introduction
简介
Measuring video quality at scale is an essential component of the Netflix streaming pipeline. Perceptual quality measurements are used to drive video encoding optimizations, perform video codec comparisons, carry out A/B testing and optimize streaming QoE decisions to mention a few. In particular, the VMAF metric lies at the core of improving the Netflix member’s streaming video quality. It has become a de facto standard for perceptual quality measurements within Netflix and, thanks to its open-source nature, throughout the video industry.
测量视频质量的规模是Netflix流媒体管道的一个重要组成部分。感知质量测量被用来推动视频编码优化，进行视频编解码器的比较，进行A/B测试和优化流媒体QoE决策，仅此而已。特别是，VMAF指标是改善Netflix会员流媒体视频质量的核心。它已经成为Netflix内部感知质量测量的事实上的标准，由于其开源性质，也成为整个视频行业的标准。
As VMAF evolves and is integrated with more encoding and streaming workflows within Netflix, we need scalable ways of fostering video quality innovations. For example, when we design a new version of VMAF, we need to effectively roll it out throughout the entire Netflix catalog of movies and TV shows. This article explains how we designed microservices and workflows on top of the Cosmos platform to bolster such video quality innovations.
随着VMAF的发展，并与Netflix内部更多的编码和流媒体工作流程集成，我们需要可扩展的方式来促进视频质量创新。例如，当我们设计一个新版本的VMAF时，我们需要在整个Netflix的电影和电视节目目录中有效地推广它。这篇文章解释了我们如何在Cosmos平台之上设计微服务和工作流，以支持这种视频质量创新。
The coupling problem
耦合问题
Until recently, video quality measurements were generated as part of our Reloaded production system. This system is responsible for processing incoming media files, such as video, audio and subtitles, and making them playable on the streaming service. The Reloaded system is a well-matured and scalable system, but its monolithic architecture can slow down rapid innovation. More importantly, within Reloaded, video quality measurements are generated together with video encoding. This tight coupling means that it is not possible to achieve the following without re-encoding:
直到最近，视频质量测...