Announced on January 3, sicong weibo “” currency”, 100000 yuan, after a less than 10 days to release the App “race” blew up weibo and circle of friends. Overnight, the online version of the happy dictionary rocketed to the top of App downloads.

What is a summit meeting?

Chongding Conference is a puzzle answering App. As long as you answer 12 questions correctly online, you can share the prize money with your friends. Note that the “prize” here is real money.

The forerunner of this model is “HQ” of the United States. HQ was launched on the App Store in August last year, and after four months, it gained 400,000 users, climbing to 27th in the total list of the App Store, and 7th in the game category. In China, there are also yingke, Huajiao Live, Pai Pai, Momo and watermelon videos.

The rules of the game are simple. The competition starts at 1 p.m. and 8 p.m. each day. After receiving the notification push from the App, users can enter the App to watch the live broadcast and participate in answering questions. At that time, a high appearance level, eloquence of the host will guide all the audience answer questions. The whole journey a total of 12 four choose a topic, in front of more to send points, the problem is in ambush. Correct answers to all questions will be rewarded with large prizes. One wrong answer, you lose your chance to reach the top. However, if you send an invitation code to your friends, you can get an extra chance to revive them.

“One Stop to the end”

The rules of the game sound familiar to many people born in the 1980s and 1990s. In the past, we have CCTV’s Happy Dictionary, which has been with us for more than ten years, and then Jiangsu SATELLITE TV’s popular program One Station to the End. And chongding is the online version of the Happy Dictionary.

This App has a very low entry barrier and is suitable for all ages. What’s more, when trivia moves from TV to online, there are no limits to how many people can participate, no barriers to entry, and anyone can just turn on their phone. Let everyone understand what is called “knowledge is money, knowledge is power”.

Even the producer of Happy Dictionary couldn’t help but sigh after the event went viral on Weibo. This could be another upend to the paradigm.

So how to make a top conference App, the next interpretation for you.

I. Functional decomposition of the summit assembly

Live,

• Play host screen • Play bonus pool rolling and grand prize screen • Host background replacement • Scene switch • Bullet screen effectsCopy the code

Questions and answers,

• Other business functions

• Notification push • Registration and login • PaymentCopy the code

The main business difficulties and key points are live broadcast and q&A.

Key points of each function

1. Live video streaming

The traditional CDN mode can be selected for live broadcast, and the delay is generally more than 2s. In this way, it is necessary to synchronize the screen and answer time between different audiences, otherwise the network delay of some audiences will be too long, resulting in a short answer time.

A more recommended approach is to use Agora’s low-latency interactive livestreams, which can last up to milliseconds. The advantage of this is that you can add more interactive elements to the program. From the example of cross-broadcast PK, we know that interaction is the gold weapon of live broadcast (according to observation, a cross-broadcast PK on Momo can attract more than 10,000 yuan in 5 minutes). For example, we can open:

• Group questions online. Friends and relatives in different places will form a group to answer the questions together through voice or video connection. After reaching the top, members will share the prize money equally. In terms of business structure, the program is a large channel with several sub-channels under it.

• Star answer. Audiences who are eliminated in the first round are often not in the mood to continue watching. If the star takes the quiz, the audience will be motivated to keep watching. What’s more, star answers are an effective way to promote the App. Dinner werewolf kill just online on the App download list, ma Dong and a lot of weird star said every night live video werewolf kill, contributed. In the star answering scenario, stars need to send their own video stream, and it must be a low-latency interaction. Otherwise the audience see the star screen and their local time difference of a few seconds, the rhythm of the answer is not unified. In the live broadcast architecture, stars link video with the main channel to send their own video streams. At the same time, these streams support social sharing via RTMP. Similar can also be derived, cross-broadcast PK answers, 1 on 1PK answers.

Sonnet’s globally deployed virtual communications network, SD-RTN, is designed for real-time transmission. Sd-rtn is based on UDP protocol and further optimized on the global network to avoid the uncontrollable delay of TCP and ensure real-time interaction. In terms of network organization, the SD-RTN network selects the optimal transmission path based on customized routes and directly transmits content to the peer end. Sd-rnt network can greatly reduce the data transmission delay, achieve a delay of 100 milliseconds. In addition, sD-RNT network has strong anti-packet loss capability. Different policies and models are adopted according to different network environments of users to ensure that service requirements can be met even when 30% packets are lost.

2. Replacement of live background

The picture of the summit meeting is slightly different from that of the live broadcast. The background of the host is replaced by a green screen. Agora’s live SDK supports live video background replacement.

In addition, you can do it more imaginatively with AR. Soundnet’s live SDK can be seamlessly integrated with ARkit and ARcore to add virtual props in real-time videos, such as virtual screens and big gold ingot.

3. Scene switch and channel message

The signaling system of acoustic network can be used to schedule scene switching and intra-channel messages. The signaling system of acoustic network is consistent with that of SD-RTN node, which can guarantee cross-network, trans-provincial, trans-national and trans-continental transmission, and support high concurrency and high availability.

4. The questions and answers

As the most relevant business logic for users, we need to ensure that users receive messages at the “millisecond level”. If CDN’s high-delay live broadcast is used, the delay will differ by several seconds due to different network conditions of users. There are related analytics costs, and the way to deal with this delay is to use synchronous push, asynchronous feedback. In other words, a single server will push questions to the moderator after he or she speaks the question.

But as the popularity of video question-and-answer sessions grows and the prize pool grows, this approach creates a new problem — cheating. Use speech recognition to read the topic, or use image recognition technology to identify the topic text on the screen, automatic search answers. This cheating process can be accomplished by taking advantage of the time difference caused by asynchronous feedback. As long as the prize money is higher than the cost of developing cheating techniques, someone will do it. However, if the low delay broadcast of acoustic network is used, the delay is only a few hundred milliseconds, there is no need for asynchronous reception, there is no time difference, and cheating is difficult. All users answered questions synchronously and gave feedback synchronously, thus eliminating the possibility of cheating from the root.

Three, business key

High concurrency is a business characteristic of the rush. Unlike ordinary live broadcasts, the summit only has one channel at a time, accommodating hundreds of thousands of viewers at a time. If you open up groups, the scene becomes one big channel, with hundreds of thousands of sub-channels. Therefore, the problem of high concurrency is more prominent than ordinary live streaming.

From the initial architecture design, acoustic network is oriented to mass and high concurrency. It uses global distribution servers and edge servers to access users nearby. When the backbone network is congested or even faulty, intelligent routing automatically avoids it, so as to ensure the high availability of services and the capacity of mass concurrency.

If you are interested in our solution, or you have any development problems, please visit our Agora q&A section to communicate with our engineers.