Live Streaming Basics: Push/Pull Workflow, Protocols, and OBS Configuration

What is Live Streaming

In one sentence: the server pushes a stream while the client pulls it, and together they form a live broadcast.

Implementation Process

1. Capture video and audio from the host using a camera and microphone.

2. Generate a push‑stream URL locally based on the room ID.

3. Use OBS to package audio and video and send them to the Tencent Cloud media service via the push URL.

4. Viewers enter the live room; the front‑end obtains the room ID and requests the playback URL from the server.

5. After receiving the playback URL, the front‑end calls Tencent Cloud APIs to get real‑time stream information.

6. Viewers can now see the live video.

Push Streaming

Push streaming (publish/up‑stream) refers to the broadcaster sending the locally captured audio‑video stream to a media server.

Key components of a push URL include:

Live code (room ID) with a BIZID prefix.

txTime – a hexadecimal UNIX timestamp indicating when the URL expires (commonly set 24 hours ahead).

txSecret – an anti‑hotlink signature to prevent URL forgery.

Combining these parts creates a Tencent‑compatible push URL.

Video Protocol Details

1. RTMP (Real‑Time Messaging Protocol) – a TCP‑based protocol suite widely used for live streaming, supported by servers such as Adobe Media Server, Red5, etc.

2. WebRTC – an API enabling browsers to perform real‑time audio/video communication, standardized by W3C.

3. UDP – some live applications build custom protocols on top of UDP for better performance in weak network conditions.

How to Obtain a Push URL

Use the platform’s backend to generate the URL with the three components above.

OBS (Open Broadcaster Software)

OBS is a free, open‑source tool for video recording and live streaming.

OBS setup steps:

Set core parameters: video bitrate (1500‑3000 kbps), output resolution (1280×720), FPS (30).

Add sources (game capture, window capture, video capture device, images, text) by right‑clicking the Sources box.

Enter the push code (live code) in Settings → Stream → Custom → URL and Stream Key.

For classic OBS, configure Broadcast Settings → Mode (Live Stream) → Service (Custom) → FMS URL and Stream Key (URL must start with rtmp:// ).

Click “Start Streaming” to begin broadcasting.

Important Notes

Ensure the computer has sufficient performance; live streaming is similar to running a game.

Upload bandwidth should be at least 2 Mbps.

Refresh the push code from the platform before each broadcast.

Pull Streaming

Pull streaming means the server already has live content, and the client retrieves it using a specified playback address.