Live streaming video latency

Question

Trying to determine what's "most" responsible for latency - the round trip my video makes from my encoder, to my server, and back down to the player in my browser.

I'm at about 12 seconds right now with a player I like. Is it buffering in my player? Buffering on the way out by FMLE?

The reason I ask is I feel I've eliminated other culprits with my little test scenario outlined below. And also, all else equal, swapping other players in produces the greatest variance in the latency. One takes it down to 4 seconds. Can't get any lower than that though.

Eliminating other culprits:

-Bad network? Nope, running it all locally. -The codec?, Nope, setting FMLE to VP6 or H.264 produces same latency. -Pushing too much data out of FMLE? Nope, 50kbs or 1000kbs produces 12 seconds -Framerate settings to intense? Nope, 5-29.97 fps changes effects motion quality but delay stays around 12 seconds.

I'm developing a small FMS based web presentation package so the latency will have to be down to a second at most. I've seen a similar package with almost no latency. Here's my test set up:

-Camera connected to Windows XP machine -Flash Media Live Encoder 3.0.1 -FLash Media Server 3.51 -Video Player - Sample dynamic streaming player in Adobe Flash Media Server productivity tools (kind of like a reference implementation for Adobe's ActionScript 3.0 Dynamic Streaming Class)

If I bounce my video off a server about 30 miles from me the result is nearly identical.

I ran a test with a CDN and a player they provided and the best I could do was 4 seconds.

Does anybody have a really fast player I can test?

Answer 1

To make low latency web stream, do the following:

1. Setup your encoder normally and point it to the media server
2. Check media server edge configuration for low latency configuration, Wowza has low latency app built-in
3. In your player, make sure your buffer is 2 second or larger.

ps. With player having buffer less than 2 second it will not work properly for most people, especially over wifi or long range links.

ps2. If your encoder is on the same LAN as Encoder, you can use low latency app for origin application as well.

ps3. You will never go below 4 seconds and reliable stream at the same time, but if you will do extreme tuning on your LAN part (no buffering for encoder at all - you can do it), by just using buffering on edge you can archive 2 seconds - I have such player but it's not public :(

Answer 2

I would like to share my experience since recently I have been researching into this world of CDN and live video streaming.

My best result has been 2 seconds latency.

I have tried a few providers and I would like to know if anyone knows of any other provider that gets to that low latency.

I achieved those 2 seconds with The Original Livestream, do not confuse with The New Livestream (16 seconds latency).

Both, The Original Livestream and The New Livestream, are part of the same group, Livestream, but it seems they target a different market segment.

They also told me that although they area still supporting The Original Livestrean, they are not longer developing it.

It is not very reassuring when they tell you that they not longer develop the platform, this is the only reason for which we have decided not to get on board with them. You will also have a hard time when you try to get support from them if you want to get access to their RESTfull endpoint for the Guide API.

Still, 2 seconds latency.

I am based in London by the way.

Please let me know if you have some other ultra low latency CDN.

Ah, the url for the original livestream is not easy to find, here it is... https://secure.livestream.com/

Answer 3

Take a look at NetStream.setBufferTime() and ns.bufferTime in the FMS documentation. Also like Robert mentioned the player has its buffer too.