A few years ago, many people were very unfamiliar with online courses. With the popularity of mobile devices and the development of audio and video technology, online education products are now flourishing. Online education products cannot serve millions of students without the support of streaming media distribution technology. This LiveVideoStackCon
2021 Audio and Video Technology Conference Beijing Station invited Zhou Xiaotian, R&D engineer of NetEase Youdao, to share with us content related to streaming media distribution of NetEase Youdao's online education business.
Written by Zhou Xiaotian
Organized by | LiveVideoStack
Hello everyone, I am from the R&D team of NetEase Youdao Premium Courses. Nowadays, audio and video have attracted widespread attention from all walks of life, and "live broadcast+" has become a hot topic. Major manufacturers have also launched a series of audio and video related services.
NetEase Youdao is an intelligent learning company whose mission is to achieve "efficient learning" for learners, relying on powerful Internet AI and other technologies By means of learning scenarios, we have created a series of learning products and services that are popular among users. In addition to online education platforms for a variety of scenarios, there are also market-leading software and hardware learning tools such as Youdao Dictionary and Youdao Dictionary Pen.
Among them, the online education business is an important business that has emerged based on the continuous maturity of audio and video technology.
Audio and video technology has a wide range of content, a long chain, and each point is very deep. Therefore, the content shared today is based on Youdao’s online education business, focusing on the streaming media distribution server part of the Youdao team.
Today’s content is divided into three parts, namely an introduction to Youdao’s online education business, the evolution of the distribution system architecture, and thoughts and practices on distribution difficulties.
1. Introduction to online education business
First, understand the needs through the online education live broadcast business form and clarify what the media distribution server should consider.
Different class types correspond to different needs. The first ones that appeared around 2013 were 1V1 courses and ordinary small class classes. Essentially, it is an educational product built with the help of RTC real-time communication mode. Later, game live broadcasts and entertainment live broadcasts became familiar to everyone, and the main form of online learning known at this stage was the video-on-demand model, such as NetEase open courses. As technology in the audio and video field matures and users’ demands for online education escalate, live online classes have developed rapidly. Live classes appeared around 2014 and received unprecedented attention after the epidemic.
Traditional large-class live classes are one-way push by teachers. In interactive large-class classes, students can further interact with teachers and get a better class experience. Student mic, screen/whiteboard, teacher video and interactive messages constitute the main content of a class.
Interactive small classes further optimize the interactivity of the product and enhance students' sense of classroom participation, learning experience and learning effect. Audio and video + H5 interactive components + flexible layout requirements also bring additional complexity.
To design services for business, you need to understand the differences between different businesses before adopting corresponding technologies. Here is a way to think about it: Take an interactive large class class as an example. A teacher and a student are connecting to each other, and then distribute the process of connecting to other students. For streaming distribution, listed on the right are some elements to consider: What level of latency and smoothness is required? At what scale? What media quality is required? How sensitive are current business lines to solution costs?
Further, different course forms can be compared horizontally in this way, and more refined needs can be obtained through their differences.
For example, compare a large-class live class with an interactive large-class class: For a session of size M, a large-class live class needs to distribute one person's information to M-1 people. This can be done through CDN-based video live broadcast. If you further want to add more interactivity to the product, it will become an interactive large class class. The addition of Lianmai will turn the simplified model into two parts. How to meet these two needs in one classroom at the same time? The simplest idea is to exchange Lianmai content through RTC on the basis of the original CDN distribution, and then distribute their information through the original CDN system. However, this will cause problems such as content delay and user switching delay.