On December 10th of 2017, we celebrated our second anniversary for LINE LIVE, our live streaming service. The service has been up and running ever since the launch with no trouble, thanks to the efforts put in by countless engineers at LINE. On this blog post, as a member of ITSC, a team at LINE running a global infrastructure system, I’d like to share with you some of decisions we had to make in the initial phase of designing and implementing the system. Back then, I had absolutely no experience in building or running a live media service.
Greetings, this is Yappo, in charge of LINE LIVE development. On this blog post, I will introduce a queue for delaying tasks, created for transmitting LINE LIVE service from users’ PC.
How LINE LIVE was broadcasting
We used to have two ways to broadcast LINE LIVE. One is to broadcast directly from the LINE LIVE app and the other is to broadcast from computers. Broadcasting from computers required using the LINE Official Account Manager site and RTMP software (or an exclusive tool). In other words, users were only able to broadcast using the LINE LIVE app, and not PC; only the LINE OA managers have been able to use computers to broadcast.
When you look at the following two sequence diagrams, you would probably think that the implementations for the two transmission types would be completely different. Much to your surprise, the fundamental designs are the same.
This is Oklahomer from LINE Corp. In this post, I’d like to explain the architecture behind the chatting function of LINE LIVE, a video streaming service.
LINE LIVE for iOS and Android has a chat feature that lets its users send comments in real-time while they are watching a live-streaming video. This not only lets users (or viewers in this case) communicate with each other, but it also lets the streamers connect with their viewers. Streamers can chat with their viewers back and forth, and sometimes plan their videos according to what the viewers say in the chat. This is why the chat is an integral part of the streaming experience.
As you can probably imagine, celebrity live streams attract a large number of viewers, and along with them a torrent of comments. Comments sent to the stream must be simultaneously broadcast to every other viewer, and effectively distributing the load has always been one of our top-priority tasks. There are sometimes 10,000 comments sent per minute on just one stream alone.
We took the possibility of large amounts of comments into consideration when we were developing LINE LIVE and presently have over 100 server instances in operation for the chat feature.