Use CDN Live Streaming

Function Overview

ZEGO Express SDK supports publishing streams to CDN (Content Delivery Network), including two functions: relaying to CDN and direct publishing to CDN. Based on this function, developers can connect RTC products and CDN live streaming products, making it convenient for users to watch and listen to live content directly from web pages or third-party players. To ensure security, CDN authentication is enabled by default when publishing to CDN.

To prevent attackers from stealing or forging your publishing URL, you can refer to CDN Stream Publishing Authentication to improve the security of your publishing stream usage.

Relaying to CDN

Relaying to CDN refers to the process of pushing audio and video streams from ZEGO audio and video cloud to ZEGO's own CDN or third-party CDN.

Relaying to CDN includes the following three ways:

Direct Publishing to CDN

Direct publishing to CDN refers to the process of pushing audio and video streams directly from the local client to CDN. Users can directly watch from web pages or third-party players through the playing stream URL address. However, because the direct publishing to CDN function does not go through ZEGOCLOUD during network transmission, developers cannot use ZEGO's real-time audio and video services.

Function Comparison

The descriptions and usage scenarios of the two functions are as follows:

Prerequisites

Before using CDN live streaming, please ensure:

• You have created a project in ZEGOCLOUD Console and applied for valid AppID and AppSign. For details, please refer to Console - Project Information.
• You have integrated ZEGO Express SDK in the project and implemented basic audio and video publishing and playing functionality. For details, please refer to Quick Start - Integration and Quick Start - Implementation Flow.

Download Example Source Code

Please refer to Download Example Source Code to get the source code.

For related source code, please view files in the "Assets/ZegoExpressExample/Examples/AdvancedStreaming/StreamByCDN" directory.

Relaying to CDN

Initialize and login room

Please refer to "Create Engine" and "Login Room" in Quick Start - Implementation Flow.

Start publishing stream

Please refer to "Publishing Stream" in Quick Start - Implementation Flow.

Start relaying

After the publishing stream is successful, call the AddPublishCdnUrl interface to add the URL for dynamic relaying to CDN, which can dynamically relay the audio and video stream that has been successfully published to ZEGO real-time cloud to a third-party CDN. The supported relay address format is "rtmp".

// After publishing stream is successful, start relaying to CDN

// Stream ID used when publishing stream
string streamID = "STREAM_ID";
// CDN address that needs to be relayed, please fill in according to the actual URL, streamID is the stream name of the publishing stream, can be customized
string URL = "rtmp://<Push domain name>/<Access point>/streamID";
engine.AddPublishCdnUrl(streamID, URL, (int errorCode)=>{
    if(errorCode == 0)
    {
        // Relay successful
    } else
    {
        // Relay failed, possibly due to network reasons causing the relay request to fail to send
    }
});

// After publishing stream is successful, start relaying to CDN

// Stream ID used when publishing stream
string streamID = "STREAM_ID";
// CDN address that needs to be relayed, please fill in according to the actual URL, streamID is the stream name of the publishing stream, can be customized
string URL = "rtmp://<Push domain name>/<Access point>/streamID";
engine.AddPublishCdnUrl(streamID, URL, (int errorCode)=>{
    if(errorCode == 0)
    {
        // Relay successful
    } else
    {
        // Relay failed, possibly due to network reasons causing the relay request to fail to send
    }
});

(Optional) Listen to CDN callback status notifications

Add/Remove relay CDN address status callback

Developers can obtain add/remove relay CDN address status callbacks by setting the OnPublisherRelayCDNStateUpdate delegate. After ZEGO RTC server relays the audio and video stream to CDN, if the CDN relay status changes, such as relay stopping or relay retrying, this callback will be received.

public delegate void OnPublisherRelayCDNStateUpdate(string streamID, List<ZegoStreamRelayCDNInfo> infoList);

engine.OnPublisherRelayCDNStateUpdate = (string streamID, List<ZegoStreamRelayCDNInfo> infoList)=>{

};

public delegate void OnPublisherRelayCDNStateUpdate(string streamID, List<ZegoStreamRelayCDNInfo> infoList);

engine.OnPublisherRelayCDNStateUpdate = (string streamID, List<ZegoStreamRelayCDNInfo> infoList)=>{

};

Relay CDN information details

Relay CDN information ZegoStreamRelayCDNInfo includes the URL of CDN publishing stream, relay status, reason for relay status change, and time when the status occurred. All parameters in ZegoStreamRelayCDNInfo are as follows:

Among them, state values are as follows:

updateReason values are as follows:

Stop relaying

Call RemovePublishCdnUrl to delete the URL for dynamic relaying to CDN. When calling the removePublishCdnUrl interface to stop relaying, please ensure that the current stream streamID exists.

// Stream ID used when publishing stream
string streamID = "STREAM_ID";
// CDN address that needs to stop relaying, please fill in according to the actual URL, streamID is the stream name of the publishing stream
string URL = "rtmp://<Push domain name>/<Access point>/streamID";
engine.RemovePublishCdnUrl(streamID, URL, (int errorCode)=>{
    if(errorCode == 0)
    {
        // Stop relay successful
    } else
    {
        // Stop relay failed, possibly due to network reasons causing the stop relay request to fail to send
    }
});

// Stream ID used when publishing stream
string streamID = "STREAM_ID";
// CDN address that needs to stop relaying, please fill in according to the actual URL, streamID is the stream name of the publishing stream
string URL = "rtmp://<Push domain name>/<Access point>/streamID";
engine.RemovePublishCdnUrl(streamID, URL, (int errorCode)=>{
    if(errorCode == 0)
    {
        // Stop relay successful
    } else
    {
        // Stop relay failed, possibly due to network reasons causing the stop relay request to fail to send
    }
});

Direct Publishing to CDN

Start direct publishing to CDN

Call the EnablePublishDirectToCDN interface before publishing stream to publish the audio and video stream directly to CDN.

ZegoCDNConfig config = new ZegoCDNConfig();
// URL needs to be filled in by developers according to actual situation, streamID is the stream name of the publishing stream, can be customized
config.url = "rtmp://<Push domain name>/<Access point>/streamID";
engine.EnablePublishDirectToCDN(true, config);
engine.StartPublishingStream("STREAM_ID");

ZegoCDNConfig config = new ZegoCDNConfig();
// URL needs to be filled in by developers according to actual situation, streamID is the stream name of the publishing stream, can be customized
config.url = "rtmp://<Push domain name>/<Access point>/streamID";
engine.EnablePublishDirectToCDN(true, config);
engine.StartPublishingStream("STREAM_ID");

Stop direct publishing to CDN

To stop direct publishing to CDN, call the StopPublishingStream interface to stop publishing stream.

After stopping publishing stream, if the next publishing stream does not need direct publishing to CDN, you can call the EnablePublishDirectToCDN interface and pass the value "false" to turn off the direct publishing to CDN function. Calling this interface during publishing stream will not affect this publishing stream.

engine.StopPublishingStream();
ZegoCDNConfig cdnConfig = new ZegoCDNConfig();
engine.EnablePublishDirectToCDN(false, cdnConfig);

engine.StopPublishingStream();
ZegoCDNConfig cdnConfig = new ZegoCDNConfig();
engine.EnablePublishDirectToCDN(false, cdnConfig);

Audience Playing Stream

• When the publishing side directly publishes to CDN, the playing side can directly play stream through streamID. Please refer to "Playing Stream" in Quick Start - Implementation Flow.

• After the audio and video stream is successfully relayed to CDN, when developers want users to play stream from CDN, they need to use the custom playing stream method with URL parameter, and cannot play stream through stream ID. For URL playing stream operation steps, please refer to "1 Configure playing stream parameters" and "2 Start playing stream" in Playing Stream by URL.