How to easily build your own live streaming low latency platform based on open source code. Final measured latency with regular player ~2s

1. Build your own low latency
live platform (∽2s)
By Jordi Cenzano
Syd<video>
June 2020

2. Credit
● 2017/07 Periscope
○ Article explained how to leverage chunked transfer in HLS to
achieve low latency
● 2018 Brightcove team, we built a prototype with:
■ Matthew Neil
■ Jon Carlos Rivera
■ Lahiru Dayanada
● FFMPEG (as always)

3. What is latency?
● The delay between when something happens and we
see it in the screen?
Latency

4. Chunk
Where is latency introduced?
● Everywhere!
GOP GOP GOP
Chunk
GOP GOP
Chunk
GOP GOP
Chunk
GOP GOP

5. Chunk
Where is latency introduced?
● Assuming
○ GOP = 2s, chunk = 6s
● Total latency = 26s
GOP GOP GOP
Chunk
GOP GOP
Chunk
GOP GOP
Chunk
GOP GOP
Encoder Transcoder Player

6. What did we do?

7. What did we do?

8. What did we do?
ffmpeg -listen 1 -i "rtmp://0.0.0.0:1935/live/stream"
-vf scale=1280x720
-c:v libx264 -tune zerolatency -b:v 6000k -g 30 -preset ultrafast -c:a aac -b:a 48k
-f mpegts "dir/fifo-720p"
-vf scale=854x480
-c:v libx264 -tune zerolatency -b:v 3000k -g 30 -preset ultrafast -c:a aac -b:a 48k
-f mpegts "dir/fifo-480p"

9. What did we do?

10. What did we do?

11. Measures, method?

12. Measures
Encoder: OBS MACos v25.0.8 (h264, 1280x720@30fps, CBR 8Mbps, 1s GOP, zerolatency)

13. Measures
Encoder: OBS MACos v25.0.8 (h264, 1280x720@30fps, CBR 8Mbps, 1s GOP, zerolatency)

14. Conclusions
● 2s glass to glass is possible
○ Just open source tools
○ LHLS principle
○ NO player modification (used Safari)
● Problems
○ ABR algorithm
○ Trade offs: Quality, stalls
○ Reliability / productionaliztion

15. Q&A - Thanks!
jordi.cenzano@gmail.com
@jordicenzano
www.linkedin.com/in/jordicenzano
jordicenzano
● Step by step guide to build this platform
○ https://github.com/jordicenzano/lhls-simple-live-platform
● Demo video
○ https://youtu.be/rTaL-9XL03g