SRT Point-to-Point Transmission Solution Caller, Listener & Rendezvous Modes

Background

In Internet-based video transmission scenarios, different network environments require different SRT connection methods.
To ensure reliable point-to-point delivery, Zowietek series products (firmware v1.1.0.7 and later) support SRT Caller, Listener, and Rendezvous modes, allowing flexible deployment between encoder and decoder devices.

By selecting the appropriate mode combination, users can establish stable SRT streaming links under various network conditions.

Products Used

 Zowietek series encoder/ decoder

Solution Highlights

1. Listener (Encoder) + Caller (Decoder) Mode

In this mode, the encoder works as the Listener, waiting for the decoder to initiate the connection.

  • The encoder generates an SRT Listener URL from Settings → Streaming → Local Stream

  • The decoder switches to Decoder Mode and disables the local server

  • The decoder selects Caller mode, fills in the Listener URL, then starts decoding

This mode is suitable when the encoder can expose a listening port and the decoder actively connects.

2. Caller (Encoder) + Listener (Decoder) Mode

In this configuration, the decoder works as the Listener, and the encoder initiates the connection.

  • The decoder switches to Decoder Mode, disables the local server, and sets the decoding type to Listener mode

  • A listening URL is generated, with a port that does not conflict with existing services

  • The encoder creates a new SRT stream in Settings → Streaming → Live, sets the protocol to SRT Caller, and fills in the decoder’s IP, port, and Stream ID

This mode is commonly used when the decoder side has a fixed public address or open listening port.

3. Rendezvous Mode on Both Encoder and Decoder

In Rendezvous mode, both devices actively establish the connection, using matching parameters.

  • The encoder sets the protocol to SRT Rendezvous, configuring a custom port and Stream ID, and enters the decoder’s IP address

  • The decoder switches to Decoder Mode, disables the local server, and selects Rendezvous mode

  • Both devices use the same Stream ID and port, and point to each other’s IP addresses

This mode is typically used when neither side can act purely as a Listener.

Outcome

1.Flexible SRT Deployment

Multiple SRT connection modes allow users to adapt to different network and firewall conditions.

2.Stable Point-to-Point Transmission

Direct encoder-to-decoder SRT links ensure reliable video delivery over the Internet.

3.Consistent Configuration Logic

All modes follow the same encoder/decoder workflow, making operation predictable once the logic is understood.

Zowietek Electronics, Ltd. established in the year of 2004, has many years of excellent experiences in the design, development and manufacture of high-quality Medical Video Recorder, 4K Surgical Video Camera, 4K Video Encoder Decoder, PTZ Camera, PTZ Controllers, and on-going development efforts. We have strong hardware, firmware, software, and R&D experiences to be the market leader in developing, manufacturing, and integration, digital video technology for professional video applications for many years. Zowietek is focusing on OEM/ODM customers worldwide. We keep presenting the latest medical, industrial and consumer video technology and full range solutions to our customers. For more information, please visit the company’s web site at enterprise.zowietek.com.

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