With the change of thinking mode, students' demand for online classroom participation and interactive experience is increasing.
In recent two years, K 12 large class has become a popular course in online education.
As the representative enterprises of K 12 online education, the future school and online school first saw the need to improve students' classroom interaction.
However, the traditional large-class teaching mode based on CDN technology has a high delay, and the one-way output mode of teachers can no longer meet the needs of online schools to further improve the classroom experience.
Therefore, Wang Si School cooperates with Agora, a real-time interactive cloud service company, to find a solution and actively upgrade its technology.
Let 0 1 class have an experience of inter-class communication.
"The teacher stood in front of the screen and said,'11What is it? Imagine "at this time, children on different screens answered" 2 "to the teacher in unison. Is this exactly the same as the online course? "Before the online school prepares for the online group class, the technical director said excitedly.
As he expected, after the online school group course was officially launched, the exchange experience was very good, which was unanimously recognized and praised by students and parents.
"The real interaction between questions and answers can arouse children's enthusiasm and attention in class and concentrate on their studies.
"Some parents accompany their children after group class and give feedback to the lecturer.
In addition, parents also told the teacher that the audio and video link design of the online school group class is very "ceremonial".
In addition, the large class collective class in the online school is a group of 6 people.
According to students' classroom performance, including participating in the exchange of answers, reading aloud, and the correct rate of answers, the course carries out "energy integral".
Finally, the teacher judges the winner according to the value of "energy integral" obtained by the group in the class.
In the group classroom mode, students compete for English reading in the classroom scene.
This interactive online class is supported by the sound network Agora.
Through the real-time audio and video (RTC) technology of sound network, Xueersi Online School has created an interactive large class teaching with lower delay.
Interactive classroom teaching breaks through the bottleneck of CDN technology, and enhances classroom interaction through the characteristics of RTC technology, such as low delay, strong synchronization and multi-channel, so that students have a better sense of presence and participation.
The highlight of this classroom scene is to emphasize the communication between students, so that students can get better learning results in a team atmosphere, especially for younger students.
It is difficult for children to concentrate for a long time, but if they have study partners, they can encourage and inspire each other and stimulate their interest in learning in a rich learning atmosphere, and the classroom effect is better.
According to the industry report of Fastdata, the average study time of users who adopt interactive online courses is 28.7% longer than that of traditional classes. This means that users recognize the effect of the interactive course learning experience.
On the other hand, RTC technology allows educational institutions to realize scene innovation independently.
Taking the school as an example, based on the combination of video and audio, the interactive modes such as the whole class dancing in class, the teacher answering questions with any name in class, the whole class reading the text together, and grouping PK are realized, creating a unique differentiated experience.
In the teaching scene of group teaching mode, the teacher is starting to connect audio and video.
Regarding the reasons for the change, the technical director of the pedant heart network school said: "Providing users with better experience and service is the top priority. Voice network RTC technology has the ability of low delay, which helps to eliminate the "cloud barrier" between users, form deep communication, and improve the intimacy and stickiness between teachers and students in the long run.
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Overcome technical problems, taking into account low delay and low carton.
Since the first day of service, the sound network has maintained a large class size in the school, and has maintained a stable and reliable service quality even if it conducts large-scale visits at the same time.
With the implicit support of SD-RTN, a software-defined real-time network that has not had an accident in the whole network for 7 years in a row, it provides a reliable transmission guarantee for the interactive experience beyond the quality of the dedicated line.
Regarding the reason for choosing the sound network service, the relevant person in charge of Xueyanxin Online School said: "In the process of contacting the sound network, I gradually found that its technology is excellent, including stability, low delay and appropriate model width.
A live online class with lower delay is equivalent to developing new software from 0 to 1, and the course scene is very complicated.
In this process, there are also many difficulties. Through the joint efforts of engineers from both sides, with the attitude of "chasing all problems to the end", they were finally overcome one by one.
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From a technical point of view, there are indeed many problems in making large classes experience low waiting time. The most important thing is short waiting time and low cost.
Teachers play a very important role in large classes.
A teacher must face thousands of students. If there is a problem with the teacher's uplink network, it will lead to a picture jam and seriously affect the teaching experience.
In the low-delay interactive classroom teaching provided by voice network, teachers' uplink network can be monitored in real time.
In the case of abnormal network and network fluctuation, the system can be switched in seconds, which ensures the online network of teachers and the smooth progress of classroom teaching.
In addition, the self-developed AUT protocol and adaptive size stream transmission strategy are adopted in network transmission, and the frame error rate is less than 0.5% even in the case of low delay of 500 ms.
In this way, the problem that CDN technology can't give consideration to low delay and low congestion is solved, and students can get a complete and smooth high-quality classroom interaction experience.
In addition, the matching of sound quality and equipment is also a difficult problem that must be overcome in the research and development of large classes in online schools.
In class, if there is something wrong with the sound, it will have a great impact on the class and is likely to lead to interruption.
Therefore, a smooth and clear audio experience is one of the keys to ensure the quality of classroom teaching.
Because teachers and students live in different environments, the two sides interact through wheat, which is prone to echo, noise and other problems that interfere with classroom experience.
Through the industry-leading 3A algorithm, the acoustic network can intelligently adapt to various environments, realize accurate sound source separation, completely eliminate echoes, and realize high-fidelity audio experience.
In addition, the AI denoising algorithm of acoustic network can suppress the common noise in the environment by separating human voice and environmental noise in real time, and extract clear human voice from the environmental noise, thus providing a high-quality and clear voice environment.
Under the background of normalization of epidemic prevention and control, the sinking market has a stronger demand for high-quality online education resources. From an academic point of view, online schools have also welcomed many students from third-and fourth-tier cities and remote areas. The learning equipment of students in these areas is complex and diverse, which requires high regional network coverage and terminal adaptation ability of technical service providers.
In this regard, the voice network has achieved network optimization in third-and fourth-tier cities and full coverage of small operators' networks, with an end-to-end high-quality transmission rate of over 99%.
At the same time, through a professional compatibility testing team, more than 20,000 terminals and a large number of peripherals are actively matched by combining actual measurement and cloud measurement to meet the compatibility coverage of different devices and models, especially the performance optimization ability of low-end machines in the sinking market, accounting for 65,438+00% of the industry.
Join hands in innovation and achieve multiple "pioneering works"
In the process of cooperation with the scientific research thinking network school, not only did the two sides jointly innovate and polish the scene, but the sound network also broke through many "firsts" and constantly challenged the technical height brought by new demands.
1. The audio and video between the two devices are perfectly synchronized, so that teachers can attend classes anytime and anywhere.
For the education department, high-quality teachers are one of the most precious resources.
If the teacher's class place is more flexible, more high-quality resources will be released.
In contrast, the school has found its own method-"Wang You" course.
This course will allow teachers to adopt the dual mobile live broadcast mode of mobile phone iPad.
In this way, teachers can not only visit the classroom through mobile devices anytime and anywhere, but also conduct classroom teaching smoothly in a weak network environment where teachers have no video but only voice, and realize unique functions such as loading mother tongue courseware and simultaneous graffiti.
In addition, the online school speakers use the mobile phone iPad dual mobile live mode to teach.
Although the advantages are obvious, even if the audio and video are pushed separately, the sound and picture are often out of sync, which is a great technical challenge.
"One machine receives audio and one machine receives video. How to achieve sound synchronization is something we have never done before.
But since there is a scene demand, we must find a way to do this.
Tang Han, head of technical service for the group class project of Yinwang School, said: "In this regard, we quickly made a plan and put it into production, and realized the plan of time stamp synchronization before the winter vacation, which made full preparations for the user experience after the traffic increased.
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2. Duplicate content audit scheme saves money and is easy to use.
Content audit has become a necessary requirement for the safety of online education live broadcast, especially in the live interactive classroom.
Before the peak of winter vacation in online schools arrived, the voice network team also anticipated the pressure in this respect.
Before the cloud recorded screenshots to achieve content review, uploading would lead to insufficient back-end resources and bear huge cost pressure.
At this time, a new content audit scheme is needed. Sound Network proposed a new scheme to switch SDK screenshots. This can reduce additional performance overhead, such as CPU and memory consumption, and greatly save costs.
But new things mean difficulties and challenges, which should not only be redeveloped, but also be compatible with the original program and suitable for students of different versions.
Finally, the content audit is realized through the most friendly scheme of SDK screenshots, which not only ensures the effect and quality, but also saves money and is convenient to use from the perspective of reducing costs.
3, the industry's first quality monitoring function
In order to get real-time feedback on the quality of classroom experience, effective end-to-end quality monitoring is needed.
Agora Analytics is the industry's first quality monitoring data analysis tool released by Sound Network on 20 18, which provides solutions for full-cycle call quality monitoring and retrospective analysis, helping enterprises and developers to find problems in time, find out the reasons and finally solve the problems.
For the interactive large class teaching scene, Crystal Ball has also achieved a number of industry-first functions.
Among them, teachers and other important role equipment, real-time monitoring of network conditions and large-channel monitoring tools have been successfully applied to the online school service of learning and thinking. Through monitoring, we can grasp the quality of classroom experience and the root of the problem at a glance, so as to solve the problems of classroom experience quickly and effectively.
Professional service: close to the needs of the scene and don't give up every student.
"The essence of real-time interaction is service, not function.
"This is the idea that Sound Network has always believed in.
After the function is online, the service can officially start.
Good service experience is the most important and continuous optimization place for voice network.
In order to provide solutions suitable for application scenarios, the sound network technical service team has been rooted in the front line for a long time and has become the group that best understands customer needs.
They use the natural advantages of RTC and their deep understanding and insight into the education industry to learn online schools and innovate scenarios and processes.
For example, the above-mentioned dual-device voice synchronization and new content audit scheme are the best solutions after repeated conflicts with scientific research institutions.
According to the characteristics of interactive large class courses, academically, online schools pay more attention to the upward quality of teachers and the actual experience of each student.
In this regard, the sound network technical service team actively proposed the optimization of service efficiency, realized the real-time monitoring of carton rate indicators in different dimensions, and found and solved the students' experience problems in class in time.
Most people may think that a student is only one tenth of all users of an educational institution, or even one million or ten million.
In addition, online school stakeholders believe that from the perspective of parents, all children are 100% parents.
Therefore, whether it is education or technical support, the problems related to children's learning must be 100%.
Not giving up all students who have difficulties in learning experience is the consensus reached by the online school and the sound network team from the beginning of cooperation.
Tang Han recalled that there used to be a boy who often had pronunciation problems in class.
After investigation, it was found that he used special audio equipment in class. This gadget was rarely used in educational scenes before.
It is understood that this equipment is the only one in his family. If the problem is not solved, it will continue to affect the classroom experience.
"In any case, it can't affect the children's classroom experience.
Tang Han said: "Through scientific research and online schools, we quickly discovered the proportion of similar equipment, and found that besides this kind of equipment, there are many special equipment also facing the same problem.
Although the total amount is less than one tenth of the total number of students, we have improved the priority and optimized the technology of this series of equipment to prevent students from affecting the classroom experience because of the limitation of equipment.
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Being able to learn online schools and improve the classroom communication experience of all students is the most important and valuable for Sound Network.
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