[heavyweight] the audio and video are perfectly synchronized with the whiteboard, which means the self-developed whiteboard SDK goes online

Time:2020-11-14

[heavyweight] the audio and video are perfectly synchronized with the whiteboard, which means the self-developed whiteboard SDK goes online
In the era of “educational technology”, more and more “black technology” is used to improve the quality of teaching. But whether it’s an offline classroom or an online classroom, one thing always exists – blackboard / whiteboard.

The blackboard in the offline classroom is the core area for teachers to write on the blackboard and write demonstration, while the whiteboard in the online classroom, in addition to displaying the teacher’s courseware, is also the carrier of the interaction between teachers and students at both ends of the screen.

Whether the whiteboard is good or not is related to the teaching quality of teachers and directly affects the students’ class experience. An excellent online interactive whiteboard should not only support diversified teaching tools such as paintbrush, text, eraser, laser pen and straight line, but also have the following three abilities:

1. Complete functions: supportVector enlarged file high definition not blurred, PPT dynamic display height restore animation”To meet the diversified needs of customers for whiteboard.

2. Interactive and efficient: guaranteeReal time synchronization of sound and picture and whiteboard, orderly cooperation of multi person operation”To make the online classroom interaction and cooperation more efficient.

3. Strong usability: solution“White board uses high bandwidth / memoryTo improve the applicability of interactive whiteboard in low-end computer, transnational teaching and other scenarios.

However, at present, most of the interactive whiteboard manufacturers in the market still have some problems, such as insufficient capacity, out of sync between audio and video and whiteboard, and inability to cooperate with multiple people, which deeply perplexes many online education platforms.

Therefore, after receiving the pain point needs of many educational customers and investigating several whiteboard / file sharing manufacturers in the industry, we decided to develop a self-developed interactive whiteboard and file sharing system, so that users can get a better experience of multi person whiteboard interaction and collaboration.

At present, the interactive whiteboard and file sharing SDK are online. Click here to download the experience app

In addition to providing comprehensive interactive whiteboard and file sharing capabilities to meet the teaching interaction needs of educational customers, the structure also specifically solves the pain points in the application process of whiteboard, helps the platform obtain better quality online classroom, and effectively reduces the work order rate and the drop out rate.

1、 White board application pain point 1: the ability of whiteboard is not complete

In online classroom, teachers should share courseware as teaching content support. However, if the whiteboard is not comprehensive in ability, the teacher will make a hard preparation of the courseware with 10 points, and only 3 points will be displayed, which will greatly reduce the teaching effect.

Too few file types are supported

Preschool education and k12 education pay attention to dynamic PPT, while subject courseware involves excel, word, PDF and other types of files. If only a few file types are supported, some courseware of teachers can not be shared and the teaching form is limited;

Courseware sharing is too vague

In the process of teaching, when students use small screen devices such as mobile phones / tablets in class, they will zoom in and view the courseware shared by teachers. However, some file sharing only transforms the files into fixed size pictures for sharing, which will cause the courseware to become very fuzzy after being enlarged and directly affect the students’ class experience.
[heavyweight] the audio and video are perfectly synchronized with the whiteboard, which means the self-developed whiteboard SDK goes online

Some whiteboard files are blurred after being enlarged

Using the instant interactive whiteboard SDK can effectively avoid the above problems:

Support dynamic ppt display, support 10 + file format

The interactive whiteboard supports the dynamic transcoding of pptx format into HTML5, and highly restores the animation content on the original ppt; supports more than 10 kinds of mainstream file formats including PPT, Doc, xls, PDF, JPG, BMP, TXT, etc.; at the same time, it also provides the complete display of multiple forms, and is compatible with different PDF files of different sizes on each page.

Vector amplification, high definition rendering of shared files

That is to say, the file sharing in interactive whiteboard uses vector amplification to present the file content as it is. Through vector rendering file content, even if zoomed in, it also presents high-definition file and whiteboard content to ensure students’ normal class.
[heavyweight] the audio and video are perfectly synchronized with the whiteboard, which means the self-developed whiteboard SDK goes online
That is, the clear effect of enlarged whiteboard file

2、 The second pain point of whiteboard application: high efficiency and difficult interaction

In addition to the perfect sharing of courseware, whiteboard, as a carrier of high-frequency interaction between teachers and students, also needs a strong interactive ability.

It is difficult to synchronize audio and video with whiteboard / file in real time

As audio and video and whiteboard belong to different manufacturers, most whiteboards in the market are difficult to achieve real-time synchronization with audio and video. This directly leads to the unsynchronized sound and picture in class. For example, the teacher says “look at the next page” and turns the page. Students will first see the next page and then hear the teacher’s voice.

It is difficult to operate in real time with multiple people

In the process of class, when teachers and students operate at the same time, it is easy to have conflicts because of the same element operation at the same time, which leads to the content of teachers and students watching is not synchronized. For example, when a teacher and a student select the same element at the same time, the teacher drags to the left, and the student drags to the right. Finally, what the teacher sees is on the left and what the student sees is on the right.

Based on the technical advantages of self-developed technology, the audio-video and whiteboard are closely combined to realize the real-time synchronization of audio-video and whiteboard, and multi-person cooperation can be carried out orderly.

Real time synchronization of audio and video with whiteboard / file

In other words, the time stamp is carried on the audio and video stream and whiteboard file signaling when streaming is pushed, and the synchronization of audio and video stream and whiteboard drawing is achieved by aligning the time stamps of the two when streaming. At the same time, aiming at the problem of multi terminal asynchronous whiteboard file caused by network anomaly, the SDK can monitor the network status in real time, and use signaling SEQ to synchronize the latest status of server in real time to ensure multi terminal synchronization.

Multi person real-time operation and efficient interaction

In the scenario of multi terminal operation at the same time, that is, the whiteboard / file sharing SDK ensures the orderly interaction through the self-developed intelligent multi person real-time conflict determination algorithm, and can realize the efficient interaction and cooperation of 100 people at the same time. Whether it is 1v1 or multi person interactive small class, it can meet the needs of courseware cooperation in the classroom.

[heavyweight] the audio and video are perfectly synchronized with the whiteboard, which means the self-developed whiteboard SDK goes online

The effect of multi person operation on white board

3、 Three points of experience: white card pain

Every online education platform has high requirements for classroom quality. Once there are problems such as stuck, dropped line and unclear hearing, it is easy to cause parents’ complaints, and the work order rate will rise, and even lead to students’ dropping out of class.

White board bandwidth memory consumption is too high, resulting in stuck

White board information transmission needs to occupy network bandwidth and memory. When the amount of data is too large, it will preempt the bandwidth resources of signaling, audio and video, and cause audio and video stuck problems. When the bandwidth resource and memory are used too much, the performance requirements of the device are also improved.

It is difficult to guarantee the quality of interactive whiteboard in transnational Teaching

Transnational teaching has become the norm. Most of the teachers on the platform come from North America, Europe or Southeast Asia. However, due to the limitation of network deployment and service nodes, some of the whiteboard services in some platforms are prone to be stuck and dropped in transnational teaching.

That is, based on self-developed technology, it optimizes signaling service from the bottom layer and compresses the amount of data transmitted by whiteboard; based on the coverage of Global 500 + service nodes, the teaching experience at home and abroad is not different.

Optimize signaling service and reduce the bandwidth and memory occupied by whiteboard

In other words, by optimizing the signaling service, simplifying the signaling protocol, reducing the amount of data in the process of synchronization and caching during whiteboard file operation, and reducing the occupation of bandwidth and memory. In different scenes such as file rendering and whiteboard stroke drawing, different rendering schemes are selected based on canvas and SVG, which can reduce the memory and CPU overhead in the rendering process on the basis of ensuring high smoothness of rendering.

Global deployment, good transnational teaching experience

That is to say, audio and video services have covered 200 countries and regions around the world. We will provide domestic and overseas service deployment according to the distribution characteristics of customer platform users, accelerate the whole station, and ensure the consistency of each data center with distributed technology, so as to truly achieve the nearest access and nearby reading, and realize ultra-low delay access for long-distance transnational transmission.

With the progress of technology, education can take off. Based on the excellent self-study ability, it is to provide interactive whiteboard and file sharing ability with more comprehensive ability, more efficient interaction and higher quality for education customers, so that each classroom teaching is more vivid and reliable.

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