Live Stream

2022-07-19
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Overview

The live streaming mainly sends the camera payload of the aircraft and the surveillance video stream of the airport to the tripartite cloud platform for broadcasting, and users can conveniently broadcast live on the remote web page.

Supported Live Streaming Types

TypeDescription
AgoraThe DJI public cloud platform is also based on the "Interactive Live Streaming Standard" function of Agora. The overall live broadcast delay is relatively low and the effect is good.
For the third-party cloud privatization deployment, Agora also provides a hybrid cloud deployment model. The data is in the customer's private server, and then a link is opened through the air gap to the Agora's public cloud. This link channel is mainly used to upgrade and operate and maintain the privatized deployed servers.
RTMPReal-Time Messaging Protocol (RTMP) is a communication protocol for streaming audio, video and data over the Internet. This protocol is based on TCP and is a protocol family that includes the RTMP and RTMPT, RTMPS, RTMPE and many other variants.
RTSPRTSP (Real Time Streaming Protocol) is an application layer protocol in the TCP/IP protocol architecture that defines how one-to-many applications can efficiently deliver multimedia data over IP networks. RTSP is on top of RTP and RTCP in architecture, and it uses TCP or UDP to complete data transmission. Compared with RTSP, HTTP transmits HTML, while RTSP transmits multimedia data.
GB28181GB/T 28181-2016 for the "Technical requirements for information transport, switch and control in video surveillance network system for public security", mainly in mainland China for security video equipment access platform for a transmission control specification. For some servers which already have 28181 downlink gateway, the data rate of DJI enterprise devices can be pushed to the server directly through this protocol.

Framework for Live Streaming

image-20220320180829159

As shown above, the aircraft flight platform is not directly connected to the tripartite cloud platform, it needs to be forwarded through the remote control or the airport. The communication between the remote control and the airport and the aircraft is still using DJI private AirLink.

The tripartite cloud platform requires pre-deployment of MQTT and streaming media server. DJI's streaming protocol supports RTMP, RTSP, GB28181 and Agora. MQTT is mainly used for message communication, configuration information setting and reading.

Dock Interactive Timing Diagram

Load Live Streaming Ability

dock livestream ability.png

Server Side call protocol to start live stream

web point to livestream.pnglivestream check  success.png

Introduction to the Interface of the API

Live Capacity

The field live_capacity is placed in the object model of the gateway device and is only pushed when there is a state change on the device side.

API: Refer to Server API > MQTT > Live Streaming > Update Live Streaming Capacity

Start Live Streaming

The server sends the command method=live_start_push to the device via mqtt, which uses the service method of the thing model to interact.

API: Refer to Server API > MQTT > Live Streaming > Start Live Streaming

Stop Live Streaming

API: Refer to Server API > MQTT > Live Streaming > Stop Live Streaming

Set Live Streaming Quality

API: Refer to Server API > MQTT > Live Streaming > Set Live Streaming Quality