SRT - Secure Reliable Transport

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Secure Reliable Transport is an open source video transport protocol. It optimises streaming performance across unpredictable networks, such as the Internet, by dynamically adapting to the real-time network conditions.


Technical/System Requirements

Setting up an input stream

See SRT Input for more information.

Setting up an output stream

1. From the vMix Settings, go to the Outputs tab and click the cog icon next to the output channel you wish to send.

2. The following settings will appear:

Enable SRT

Check this box to enable the SRT output.

Listener: Listen on the specified Port on all network adapters on the computer for connections. Hostname is ignored.
Caller: Connect to the specified Hostname and Port.

Rendezvous: Connect to the specified Hostname and Port. The other side must also be set to Rendezvous with an identical port number specified.
This mode allows connecting through most firewalls automatically.


Specify the latency of the connection in milliseconds to adapt to network congestion.
The higher this value, the better SRT can handle difficult network conditions.
As a general rule this should be set to at least 4x the ping time destination IP. So 20ms would require a latency setting of at least 80
This must be set to the same value on both ends.


Specify a password to encrypt the connection. This password must be used by both sides for the connection to be established.

Stream ID

Optional Stream ID that may be required by your streaming provider to uniquely identify the stream.


Select one of the built in compression profiles from the list or click the cog icon to customise the encoding settings.

Video Codec

Select either H264 or HEVC as the video compression method.

Video Bandwidth / Audio Bandwidth
Specify the bandwidth in bits per second for Video and Audio. Example 2000000 = 2mbps and 128000 = 128kbps.
Audio bandwidth is total for all channels. For example for 8 channels, 384 = 48 kbps per channel.

Use Hardware Encoder

Use accelerated encoding where available on the graphics card. NVIDIA GeForce cards (and some low end Quadro cards) are limited to 2 simultaneous encodes per system.
This includes the Streaming and Recording features in vMix, so care should be taken to ensure this tick box is only enabled at two locations when using these types of cards.
(such as 1x Stream and 1x SRT)

Use Low Power Encoder

Some Intel Graphics drivers included support for "VDENC" which is a low power, high performance encoder built in to some CPUs.
Tick this box to enable using this encoder where available.

Audio Channels

Specify the audio source for this output. A maximum of 8 channels of audio is supported by AAC.


Optionally specify a resolution to downscale to. Only progressive formats are supported.

Alpha Channel

This setting must be set to None as alpha is not supported by the video codecs used by SRT.