「 Common problems of converged communication 」 The monthly magazine will meet you at the end of each month , The monthly magazine mainly includes a collection of wrong questions 、 Knowledge gas station 、 Technology plus meal three plates , Collect the error prone problems and problem-solving ideas in the process of practice , Share cutting-edge information and technology dry goods in the field of integrated communication , Speed up your development , Add bricks and tiles to your advanced road .

Content overview of this issue

Look here ！ Get around the hole that others have stepped on ！

In the process of listening to music and communicating, the voice becomes smaller .

After calling the interface leaving the room , The camera is still in use .

When the audience switches to the wheat Lianmai , Hear the voice of the anchor and repeat it twice .

Web After the end bypass is pushed , The pull end cannot pull the flow .

Turn the camera off and back on , The camera is switched and cannot be maintained .

Use Web In the end pure audio call scenario , I can't hear a voice .

These knowledge points, you know ？

Why failed to open the camera ？

How to deal with video blur ？

Why is there a Caton in the video ？

One 、 Set of wrong questions

Talking room

Difficult problems 1： Voice scene in the chat room , In the process of listening to music and communicating, the voice becomes smaller .

Error prone grade ：

Reasons for wrong questions ：

The sound volume and voice volume settings are unreasonable , Resulting in poor audio effect at the receiving end .

Their thinking ：

（1）setAudioMixingPlaybackVolume The recommended volume setting is no more than 25, After that, the experience of voice communication may be affected ;

（2）adjustRecordingSignalVolume The default volume of this interface is 100, It is not recommended to adjust .

Difficult problems 2： After calling the interface leaving the room , The camera is still in use .

Error prone grade ：

Reasons for wrong questions ：

Use nertc-web-sdk when , Repeated calls to some interfaces .Stream.init（ Initialize the audio and video stream object ） In the case of being called twice , Two different video streams are created locally , Use the camera device at the same time . stay Client.leave（ Leave the audio and video room ） when , Only one stream of device usage is ended , So that the camera is still in use .

Their thinking ：

In business , Need to manage Stream.init Number of calls and Stream Object lifecycle , Every Stream Just initialize once , To ensure the normal use of audio and video .

Interactive live broadcast

Difficult problems 3： When the audience switches to the wheat Lianmai , Hear the voice of the anchor and repeat it twice .

Error prone grade ：

Reasons for wrong questions ：

In interactive live broadcast application , Switching between spectators and wheat fans , Involving players from CDN Pull flow switch to join RTC The room subscribes to the main broadcast video . After the audience successfully connected wheat , Join the audio and video room and subscribe to the main audio and video without stopping the player , Cause the anchor audio to be played repeatedly from the player and the audio and video room at the same time .

Their thinking ：

Interactive live broadcast , The standard implementation process of wheat Lianmai ：

（1） Lian Mai succeeded

（2） Quit playing , Release player instances and resources mLivePlayer.release();

（3） Initialize audio and video and enter the audio and video room

（4） Subscribe to remote audio and video

Difficult problems 4： Web After the end bypass is pushed , Occasionally, the flow end cannot pull the flow .

Error prone grade ：

Reasons for wrong questions ：

Push the bypass flow （addTasks perhaps updateTasks） And push RTC Room flow （publish） Timing error , This leads to the lack of data source during interactive live streaming

Their thinking ：

Before pushing the bypass flow, ensure that the corresponding flow has been in RTC The room was published successfully , So we need to publish Call... After success addTasks;

If the bypass layout also contains the flow of other users , You have to receive the corresponding user's stream-added/stream-subscribed After the stream callback, call addTasks perhaps updateTasks.

General problems

Difficult problems 5： When using audio and video , Turn the camera off and back on , The camera is switched and cannot be maintained .

Error prone grade ：

Reasons for wrong questions ：

Switch video usage NERtc#enableLocalVideo() Interface , At this time, the front or rear camera is opened by the last call setLocalVideoConfig In the middle of frontCamera Parameters determine , If you're calling enableLocalVideo Then reset setLocalVideoConfig Interface frontCamera Parameters , Then turn on the corresponding camera based on this parameter .

Their thinking ：

setLocalVideoConfig Configure the interface for all parameters , When calling this interface repeatedly ,SDK All previous parameter configurations will be refreshed , Subject to the latest transmission parameters . Therefore, you need to set all parameters every time you modify the configuration , Unset parameters will take the default value .

Audio call

Difficult problems 6：

Use Web In the end pure audio call scenario , After receiving the subscribed remote video stream , I can't hear a voice .

Error prone grade ：

Reasons for wrong questions ：

Web After receiving the subscribed remote audio, the client needs to call play Method play .

Their thinking ：

stay stream-subscribed Callback （ Indicates subscribing to the remote voice / Video streaming succeeded ） Inside , call play To play remote audio and video streams , here audio and video All recommended settings are true.

Two 、 Knowledge gas station

Why failed to open the camera ？

There are many reasons why the camera fails to open , You can refer to the following steps for troubleshooting ：

Confirm whether the camera permission is turned on .Android、iOS/macOS All systems have permission management , Please check... In the system settings . meanwhile Android Some security software on also manage permissions .
Check if there are other apps occupying the camera . Close other apps , Restart the phone and try again .
Camera hardware problem . Open the system's own video capture program to see if you can record .

How to deal with video blur ？

Video blur is generally caused by low video bit rate or resolution .

confirm SDK Medium resolution settings , You can setLocalVideoConfig Method to set video related properties .
Try 4G/5G Connect , Or other WiFi The signal eliminates network problems .
Whether the receiving end accepts a large stream or a small stream , If it is a small flow, you can call the interface to apply for a large flow and close the small flow .
Before video processing , Please turn off the pre-processing to test , Eliminate pre-processing problems .

Why is there a Caton in the video ？

The video Caton problem is generally caused by the network 、 Equipment performance and other reasons .

Judge whether it's continuous or one-off . The one-off jam is caused by the randomness of the network and equipment , Normal phenomenon .
Check network status , Determine whether the connection is normal , Whether you can surf the Internet .
If the network connection is normal but still stuck , Please try changing the network connection , Check whether it is still stuck when the network is in good condition .
If the network is good and conditions permit , Please try to replace the device .
Before video processing , For example, beauty, etc , Please close the pre-processing first , Check whether the jam is caused by pretreatment .

3、 ... and 、 Technology plus meals

information ｜WebRTC M97 to update

Description of content ：WebRTC M97 Currently in Chrome Available in the stable version of , contain 10 Multiple bug fixes 、 Enhance and stability / Performance improvements .

Technical dry cargo | C++ Three of the four characteristics ：concept Feature details

Description of content ： The evolution of templates is C++ A very important line in the history of development , The author thinks concept Is the biggest feature of this line , This article will explain in detail C++ Of concept characteristic , With a view to C++ Have a deeper understanding .

Technical dry cargo | WebRTC ADM Source flow analysis

Description of content ： This paper is mainly based on WebRTC release-72 Source code and relevant experience accumulated by cloud audio and video team , This paper mainly analyzes the following problems ： ADM（Audio Device Manager） What is the architecture ？ADM（Audio Device Manager） How about the start-up process of ？ADM（Audio Device Manager） How the data flows ？ This paper mainly analyzes the relevant core processes , So that when you need it , Can quickly locate relevant modules .