Also read: SRT playback stats and paywall for Nimble Streamer, RIST in Larix Broadcaster, SRT playback on tvOS and Android TV and more in our Q3 news digest
Secure Reliable Transport
SRT support in Nimble Streamer
What is SRT
Secure Reliable Transport (SRT) is a UDP-based transport technology that optimizes streaming performance across unpredictable networks.
SRT is applied to contribution and distribution endpoints as part of a video stream workflow to deliver the best quality and lowest latency video at all times.
- SRT detects and adapts to the real-time network conditions between the two endpoints.
- SRT helps compensate for jitter and bandwidth fluctuations due to congestion over noisy networks.
- Error recovery mechanism minimizes the packet loss typical of Internet connections.
- AES 128/256 bit encryption is also supported for end-to-end security, keeping your streams safe from prying eyes.
Softvelum is an active member of SRT Alliance, a group dedicated to managing and supporting the open source implementation of SRT.
SRT features in Nimble Streamer
Nimble Streamer has full support for SRT protocol.
- Both Push (Caller) and Listen delivery modes are supported
- Both Listen and Pull receive modes can be used to get SRT streams for further processing.
- Rendezvous mode can be used for both receiving and sending data.
- Custom latency and maxbw parameters are supported for re-transmission control, we highly recommend using them both for all connections.
- One-to-many multi-point listener: multiple Pull-mode clients can be supported when working in "Listen" mode.
- SRT playback stats and paywall protection feature set similar to other playback protocols.
- FEC (forward error correction) filter is supported.
- AES-128 bit encryption provides stream security.
- Both IPv4 and IPv6 are supported.
- Multiple programs can be sent via single SRT channel.
- Mux rate can be set correctly - Nimble Streamer has 100% PCR accuracy, 0ns PCR drift and PCR interval <20 ms according to StreamGuru.
This is typically used for precise testing of channel throughput.
- You can use Nimble Streamer API to get SRT sender and receiver statuses.
Take a look at full SRT setup instructions to try it in action. Also read Streaming SRT via OBS with Nimble Streamer and Larix Broadcaster to see a brief example of OBS usage with Nimble Streamer.
streamid parameter support
- As a sender, Nimble supports streamid in Push mode.
- As a receiver, Nimble supports streamid in Listen mode as part of Publisher Assistance Security Set.
SRT flexible publication management: SRT Publisher Assistance Security Set (SRT PASSet)
Nimble Streamer provides wide security and management feature set for SRT receiver Listen mode.
- Accept streamid parameter with "application/stream" format.
- Make per-application and per-stream authentication with user and password.
- Apply any SRT parameters to each individual stream and even individual publisher.
- Apply allow and deny lists for IP addresses on server and stream level.
- Manage published streams via publish control framework.
Read the following articles to learn more about PASSet:
Hot swap capabilities allow switching between source origin and substitute streams with no glitches or artifacts:
These features are available for SRT once you enable instant inactivity disconnect for MPEGTS-based streams
for your server instance.
Installation and usage
To start using SRT in Nimble Streamer, you need to do the following:
- Install Nimble Streamer if you haven't done it yet, or upgrade it to latest version.
- Install SRT package for Nimble Streamer to add respective functionality.
- Follow Setting SRT in Nimble Streamer article to see how to set up SRT streaming in all modes using WMSPanel control web service.
Related Nimble Streamer features
Nimble Streamer covers wide variety of live streaming scenarios so SRT can be used as an element in complex delivery scenarios.
- Live Transcoder allows processing incoming streams to change the content according to your business logic.
This includes decoding, applying various filters and encoding. All setup is performed via drag-n-drop web UI.
- Process incoming streams via RTMP, NDI, RTSP, MPEG-TS, HLS and SRT.
- Produce RTMP, NDI, RTSP, MPEG-TS, HLS, MPEG-DASH, Icecast and SRT outgoing streams.
- Generate thumbnails for output streams.
- Use DVR feature set to record incoming live streams and provide further playback via MPEG-DASH and HLS.
- Usage snapshots show examples of combined usage of Softvelum products.
SRT in other products
SRT is supported in all major products of Softvelum besides Nimble Streamer.
This includes Larix Broadcaster streaming app and Larix Player.
Visit SRT reference page for more information and links.
Free trial of WMSPanel included
Easy installation and upgrade
Nimble Streamer can be installed in a couple of small steps and upgraded to the latest version by running two or three simple commands in console.
Let us know if you need any help and search through our documentation to find more information.