Wowza with cmaf or llhls reduce latency

[Nguyen_Canh_Toan]

HI @all!
Hope you have a nice day.
I am currently configuring according to the following 2 links
A. CMAF HLS/DASH
https://www.wowza.com/docs/stream-using-cmaf-with-wowza-streaming-engine
B. You’ll need to setup a 2nd application for LL-HLS here:

https://www.wowza.com/docs/deliver-apple-low-latency-hls-live-streams-using-wowza-streaming-engine
I have a question regarding using cmaf and llhls on wowza about latency :
I pushed rtmp to wowza server from OBS and use extension chrome hls player to view clock time but latency about 15-30 seconds.

P/s :

• Wowza server : 4.8.0
• Setting
  • cmafSegmentDurationTarget :2000 ms
  • cmafPlaylistSegmentCount : 3

I want to reduce the delay to about 3-5 seconds.
Do you have any advice for me?
Thank you!

[Rose_Power-Wowza_Com]

@Nguyen_Canh_Toan

extension chrome hls player

Hello @Nguyen_Canh_Toan thanks for reaching out, I think what stands out here for me is that not all HLS players support LL-HLS and I am not sure about that chrome extension player, but I don’t think it does based on a bog I read:

On the other hand, players that had not been optimized for LL HLS, like the Native HLS Playback Chrome extension, showed latency as high as 26 seconds, which tends to prove that LL HLS is backward compatible on non-LL HLS players, though at normal latency.

There are player that do support LL-HLS and you can see some of those here:

How to Implement Low-Latency HLS (LL HLS)

[Rose_Power-Wowza_Com]

You can test LL-HLS streams by entering the playback URL in the Safari browser on iOS 14, other native apps on devices running iOS 14, or any player that supports LL-HLS. If a player supports HLS but not LL-HLS, it will default to playing LL-HLS streams as standard HLS at a higher latency.

https://www.wowza.com/docs/deliver-apple-low-latency-hls-live-streams-using-wowza-streaming-engine#test-stream-playback10

[Nguyen_Canh_Toan]

@Rose_Power-Wowza_Com

There are player that do support LL-HLS and you can see some of those here:

Hi @Rose_Power-Wowza_Com!
I pushed with link rtmp://x.x.x.x:1935/livecmaf
and load from http://players.akamai.com/players/hlsjs with link http:///x.x.x.x:1935/livecmaf/stream01/playlist_sfm4s.m3u8 but it still latency about 15 seconds

Please support me!

[Rose_Power-Wowza_Com]

Can you tell me what you have for your cupertino settings:

cmafLLChunkDurationTargetVideo
Did you see in the docs that it cannot exceed the cmafSegmentDurationTarget?

Reduce the number of some of these properties, you may have to experiment to see what kind of latency you get.

https://www.wowza.com/docs/configure-cmaf-packetization-in-wowza-streaming-engine

Also make sure you are starting on a keyframe- that’s very important because the video won’t start until it seeks out the keyframe.

Please get a support ticket so we can spare you the trouble of trying to troubleshoot this, we need full access to your configuration and files to accurately diagnose the problem.

[jungin.kim]

For a single stream, we confirmed that the LL-HLS delay time is 5-6 seconds in Safari.

Is this same 5-6 second delay observed with multiple streams (ABR) as well?

I’m currently testing this on my iPhone, but whenever I load it, I experience a delay of 20 seconds, though it drops to 5-6 seconds if I immediately adjust the progress bar.

[Jason_Hilton]

Hi Jungin,
I was unable to reproduce the behaviour you described. As such, it’s possible that this issue is either limited to your environment or the player you’re using.

I tested playback using the Wowza-Flowplayer demo page and recommend you test with this player too as this should help to narrow down the cause of this problem.

If you’re still having issues with latency of adaptive bitrate streams with the LL-HLS protocol, I recommend that you create a ticket with the Technical Support Team and ensure to provide them with the configuration files, log files created during the reproduction of the issue and a copy of the .smil file used for playback.

If the stream is live and publicly available, the HLS playback URL that’s used would also be helpful for the Technical Support Team to troubleshoot further. Please share this in the ticket (not the public forum).

Regards,
Jason Hilton
Senior Technical Support Engineer
WOWZA | The solution you start with, the partner you scale with.

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