SRT Stream Settings

The following tables list the TS over SRT-specific parameters:

Connection

Setting	Default	Description/Values
Mode	Listener	Specifies the SRT Connection Mode (to simplify firewall traversal): Caller: The decoder acts like an SRT caller and connects to a server listening and waiting for an incoming call. Listener: The decoder acts like an SRT listener and listens for a server to connect to it. Rendezvous: Allows calling and listening at the same time. To simplify firewall traversal, Rendezvous Mode allows the encoder and decoder to traverse a firewall without the need for IT to open a port.
Address	n/a	(Caller and Rendezvous modes) Specifies the destination IP address for the SRT stream.
Port	n/a	(Listener mode only) Specifies the UDP local port for the SRT stream.
Source Port	Auto-Assign	(Caller and Rendezvous modes) Specifies the UDP source port for the SRT stream. If not filled in, a (default) source port will be assigned. Note This simplifies firewall configuration as the firewall/NAT rules can be precisely tailored to the SRT stream.
Destination Port	n/a	(Caller and Rendezvous modes) Specifies the destination port for the stream.

SRT Settings

Setting	Default	Description/Values
Latency	125	Specifies how long the decoder will buffer received packets. Range = 20 - 8000 ms Note The SRT buffer, configured as “Latency’”, is the time reserved in the decoder to recover missing packets. Because real-time video cannot be paused, restarted, slowed down, or accelerated, the buffer adds a fixed delay in the end-to-end latency. If a lost packet cannot be recovered, this may result in an A/V artifact. In this case, you should increase the SRT latency as it is likely too low. Please see the SRT Deployment Guide for tuning guidance.
Encrypted	Off	Toggle to On to enable decryption of encrypted streams.
Passphrase	n/a	(Encrypted must be On; must match encoder passphrase) This parameter is required if the stream is encrypted and is used to retrieve the cryptographic key protecting the stream. Range = 10-79 UTF8 characters
Authentication	none	(Only available if Encryption is enabled) Configures Authenticated-Encryption with Associated-Data (AEAD). AEAD not only requires a key to decipher the encrypted stream, but also binds it to certain associated data. This associated data (composed of some non-confidential information about the stream) is integrity-protected, which allows users to determine if their streams have been tampered with or not. Options are: None - Default for Caller and Rendez-vous modes. Not available for Listener mode. Auto - Default for Listener mode. Not available for Caller or Rendez-vous modes. AES-GCM - Available for Caller, Listener, and Rendez-vous modes. Note Setting the authentication to Auto allows the Listener to accept Callers with authentication set to either None or AES-GCM. Listeners with the authentication set to AES-GCM will only accept Callers which are also set to AES-GCM.

SRT Access Control

Setting	Default	Description/Values
SRT Access Control	Off	(Caller and Listener modes) Toggle on to enable SRT Access Control.
Format	Standard Keys	Select the format to configure the Stream Publishing ID: Standard Keys: Simplifies defining the Stream Publishing ID. The Stream Publishing ID field is read-only and auto-fills when you fill in the Resource Name and User Name fields. Example Standard Keys format Stream ID: #!::u=admin,r=haivision1 ,m=publish Custom: Select Custom to enter the Stream Publishing ID using your own format. Tip If you first select Standard Keys format and fill in the Resource Name and User Name fields, you can then modify or complete the resulting Stream Publishing ID by switching to Custom format. See Configuring SRT Access Control.
Resource Name	n/a	(Standard Keys only) Identifies the name of the resource and facilitates selection should the listener party be able to serve multiple resources.
User Name	n/a	(Standard Keys only) The user (authorization) name that is expected to control which password should be used for the connection. The application should interpret it to distinguish which user should be used by the listener party to set up the password.
Stream Publishing ID	n/a	(Standard Keys) Read-only/auto-filled when Resource Name and User Name fields filled in. (Custom Format) Enter the Stream Publishing ID using your own format.

Stream Conversion

Setting	Default	Description/Values
SRT to UDP Stream Conversion	Off	Toggle to On to enable UDP retransmission of SRT streams on the local network. Note The SRT input stream may be encrypted and includes error correction. Enable this to rebroadcast the SRT stream on the local LAN without the encryption and error correction elements over UDP. A single multicast or unicast destination TS/UDP stream is supported for re-streaming.
Address	n/a	Specifies the destination IP address for the stream.
Destination Port	n/a	Specifies the UDP source port for the stream.
TTL	64	(Time-to Live for stream packets) Specifies the number of router hops that IP packets from this stream are allowed to traverse before being discarded. Range = `1..255`
ToS	184 or 0xB8	(Type of Service) Specifies the desired quality of service (QoS). This value will be assigned to the Type of Service field of the IP Header for the outgoing streams. Range = `0..255` (decimal) or `0x00..0xFF` (hex) Important A DiffServ or DSCP (Differentiated Services Code Point) value must be converted to a ToS precedence value. For example, AF41 or DSCP 34 becomes ToS 136. For more information, see RFC2474. Note The ToS setting must be chosen so as to not interfere with Voice over IP systems and other equipment that may reside on your network. For example, when the ToS value for a stream is set to 0xB8, it can interfere with some third party Voice / IP Telephony systems.