SRT Low Latency

SRT Low Latency

"Secure Reliable Transport (SRT) is an open source video transport protocol that utilises the UDP transport protocol"


  • UDP is faster TCP
  • Lost packet?  SRT can retransmit lost packets quickly
  • AES encryption
  • Transport protocol, so you can use any video format, codec like HEVC, AV1 (Also AV2, VVC in the future)
  • Low latency ~1000ms

SRT test on local network

I install OBS, ffmpeg and srt-live-transmit on localhost. latency results around 300ms. Please note that I test on my low spec desktop (AMD 3200g). I believe that the video encoder process is a key factor of the result.

SRT End-to-End testing

Now, I use OBS to stream video to the SRT server at Singapore (RTT from Thailand around ~30ms) then playback from Thailand. The latency is around ~400ms which is not bad. However I have not optimized much, so may be a better result if I optimize all factors.

Test #1 ~530ms

Test #2 ~365ms

Test #3 400ms

What I Config