To fight the epidemic, let’s take a cool online exam

With the rapid development of mobile Internet, mobile phones have become a part of the body of middle and young people, who never leave their hands from waking up to the last minute before going to bed. In recent months, online learning and exams have once again become hot topics on the Internet due to the epidemic.

The question is, how can online learning and testing ensure the quality of students’ learning and testing? Gradually, all kinds of online teaching and online examination functions emerged in various network organizations, and the state also introduced the policy of attending classes without suspension. As a Web side development or very curious audio and video this function. Rongyun was selected as the third party of audio and video, which opened my exploration journey.

Function idea

(1) The student side does live broadcasting, and one student has three views (camera collection, screen sharing, and mobile phone collection) which are transferred to CDN through the background of Rongyun. (2) The teacher subscribes and plays multiple live images of students at the same time, and can also check the screenshots of the videos collected by the students or the videos of the first few minutes; (3) When the teacher finds that a student needs warning or answering questions, the teacher can enter the room where a single student is and communicate with the student through the mic in real time.

Student side implementation

(1) I use “anchor” for the role of students; In multi-camera shooting, two devices are needed, generally a PC and a mobile terminal; One account is used to log in to the application at the two ends, but two UUIds are used when joining rongyun audio and video room (there are some pits here, which took a long time to understand after debugging. The PC side creates and joins the live broadcast room to push the audio and video stream; Then the mobile terminal joins the corresponding room and also sends audio and video streams; (You can turn off the microphone and see the business scenario requirements); After debugging, the test can be carried out normally.

Here is the host process documents: docs. Rongcloud. Cn/v3 / views/rt…

(2) Students log in to the examination system through a browser on PC;

(3) After login, the computer camera will collect students’ positive real-time images. Students can also send out screen sharing. The login application on the mobile phone will join the same examination room and be placed behind students to capture the overall view of the examinee.

(4) The student application can call the screenshot interface provided by Rongyun to take snapshots at any time, so as to detect whether the image recognition module is cheating or not;

(5) Face picture, whole body image and screen shared image uploaded by students; A stream will be synthesized on the rongyun server.

Teacher-side implementation

(1) The role of the teacher is “audience”; Subscribe to multiple student output images as a whole; Viewers interface documents: docs. Rongcloud. Cn/v3 / views/rt…

(2) When teachers find problems, they can view the playback of the first few minutes of the specified student’s live stream. Real-time recording is required and recorded at CDN.

(3) When a warning or question answering is needed, the teacher can enter the room where a single student is and communicate with the student in real time. You can only send audio when joining. To answer the teacher warned the reference document: docs. Rongcloud. Cn/v3 / views/rt…

Record retention

(1) Rongyun Cloud can be used to record; All video streams uploaded by each student can be recorded in a picture to meet the requirements of the examiners to check whether students cheat in the whole process of the exam after the exam. Melts the recording time end, more than you can upload object storage, can choose according to the requirements in audio format reference documentation docs. Rongcloud. Cn/v3 / views/rt…

Pictured above,

The students end

The teacher side