Pre-call tests
In video calling scenarios that demand high communication quality, pre-call detection helps identify and troubleshoot issues beforehand, ensuring seamless real-time interaction.
This page shows you how to use Video SDK to run pre-call tests to identify and troubleshoot communication quality issues in your app.
Understand the tech
Pre-call testing typically covers two aspects:
-
Equipment quality test
To test whether the local microphone, speaker, and camera are working properly, you run an echo test. The basic process of conducting an echo test is as follows:
-
Network quality analysis
The quality of the last mile network affects the smoothness and clarity of the audio and video that the user sends and receives. Last mile refers to the last leg of communication network between the edge server of the SD-RTN and the end-user devices. Network quality analysis enables you to get feedback on the available bandwidth, packet loss rate, network jitter, and round-trip delay of the upstream and downstream last-mile networks. The following figure shows the basic process of running a last-mile probe test.
Best practice is to run the device test first and then perform a network test.
Prerequisites
Ensure that you have implemented the SDK quickstart project and that your app has obtained permissions to use the relevant devices.
Implement pre-call testing
This section shows you how to implement pre-call testing in your project.
Equipment quality test
The SDK provides the startEchoTest
[3/3] method to test the network connection and whether the audio and video devices are working properly. Refer to the following steps to implement the device quality test:
-
Before joining a channel, call
startEchoTest
[3/3] withEchoTestConfiguration
. Specify the channel name, whether to test audio or video, and the time interval for the echo. -
After starting the test, face the camera and speak into the microphone. The user's audio or video is played back after a short delay. If the playback is normal, it means that the user's devices and upstream and downstream network are working normally.
-
To stop the test, call
stopEchoTest
, and then calljoinChannel
to join a channel.
Using startEchoTest
[3/3] to test an audio device and a video device at the same time may result in a brief audio-video desynchronization of the test results.
To implement running an echo test in your app, refer to the following code:
Network quality analysis
The SDK provides the startLastmileProbeTest
method to probe the last-mile network quality before joining a channel. The method returns information about the network quality score and network statistics. Take the following steps to run a last-mile network quality probe test:
-
Before joining a channel or switching user roles, call
startLastmileProbeTest
to start the network test. Set the probe configuration and the expected maximum bitrate inLastmileProbeConfig
. -
After you start the test, the SDK triggers the following callbacks:
-
onLastmileQuality
: This callback is triggered two seconds afterstartLastmileProbeTest
is called. It provides feedback on the upstream and downstream network quality through a subjectivequality
score. -
onLastmileProbeResult
: This callback is triggered 30 seconds afterstartLastmileProbeTest
is called. It returns objective real-time network statistics, includingpacketLossRate
, networkjitter
, andavailableBandwidth
.
-
-
Call
stopLastmileProbeTest
to stop last-mile network testing.
To implement network quality testing in your app, refer to the following code:
Reference
This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.
Troubleshooting device and network issues
If you encounter problems while running pre-call tests, first ensure that you have implemented the API calls properly. To troubleshoot device and network issues, refer to the following table:
Problem | Solution |
---|---|
Can't hear sound when testing audio devices. |
|
Cannot see the screen when testing video devices. |
|
Poor uplink network quality detected (packet loss > 5%; network jitter > 100ms) |
|
Poor downlink network quality detected (packet loss > 5%; network jitter > 100ms) |
|
Sample project
Agora provides an open-source PreCallTest sample project for your reference. Download and explore this project for a more detailed example.