rtsp2webrtc has 4 seconds of latency

[kc7b...@gmail.com]

I am playing with Kurento and the rtsp2webrct application (https://github.com/lulop-k/kurento-rtsp2webrtc) to see if I can stream my live video sources (IP cameras) to a web page. I need low latency as the user will be panning and tilting the camera while watching the video. I was successful in installing Kurento and rtsp2webrct but when I play the video I see 4 seconds of delay between playing the video with VLC and playing the video through rtsp2webrct. I am new to WebRTC technology. Is there a way to reduce the delay in playing WebRTC video?

David

[Luis Lopez]

Your problem may be originated for several reasons:

1. WebRTC congestion control mechanisms. If the outgoing BW of your WebRTC connection is under the incoming BW of your RTSP connection, media will buffered and latency will increase. If this is the problem you are having, latency should be increasing with time, so that the longer the duration of the session the longer the latency. For solving this, you may need to improve the connectivity between KMS and the WebRTC browser.

2. Incompatibility of your encoded stream with GStreamer. GStreamer is somehow much more restrictive than VLC with non-compliant H.264 implementations. We have seen in many occasions RSTP streams that are not fully compliant and that VLC decode seamlessly but that GStreamer decode with problems, which may include latency. For finding if this is your problem, you may create a simple GStreamer pipeline receiving directly the RTSP stream into your screen and see what happens.

Best regards.

Luis Lopez
Kurento.org Project Coordinator
+34 914 888 713 • lu...@kurento.com • prof.luis.lopez • • • •

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El 28/09/2015, a las 20:45, kc7b...@gmail.com escribió:

I am playing with Kurento and the rtsp2webrct application (https://github.com/lulop-k/kurento-rtsp2webrtc) to see if I can stream my live video sources (IP cameras) to a web page. I need low latency as the user will be panning and tilting the camera while watching the video. I was successful in installing Kurento and rtsp2webrct but when I play the video I see 4 seconds of delay between playing the video with VLC and playing the video through rtsp2webrct. I am new to WebRTC technology. Is there a way to reduce the delay in playing WebRTC video?

David

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[kc7b...@gmail.com]

Thanks for the response. I am trying to receive video only. This application tries to play live video from an IP Camera and does not transmit any video or audio itself. Is there some way I need to explicitly tell WebRTC that I am not going to send any data?

Also, I've tried with multiple IP Cameras and am still seeing 3-4 seconds delay. I am using an HTML5 <video> tag for the video on FireFox on Ubuntu 14.04. Could whatever FireFox is using to play video in the <video> tag be causing the 3-4 second delay? Is there anyway to test that or disable that? Unfortunately, I am unsure how to exactly setup gstreamer to stream directory to the screen in Ubuntu (I work mostly in Windows).

Thanks, David

[kc7b...@gmail.com]

I was finally able to get gst_launch to work on my install and it is showing a 4 second delay in playing the video. When using Kurento is there a way to fix this delay when using gstreamer to transcode an IP camera for WebRTC?

David 

[Luis Lopez]

Then, it seems that the origin of your problem is not on Kurento but on GStreamer encode/decode. We have GStreamer with many RTSP cameras and in general we are not finding such kind of problem. Hence, the problem might be related to the interaction of GStreamer with your specific stream encoding. I'm afraid that solving that types of issues is not simple and that you'll need to dig deep into GStreamer for figure out what may be happening.

Best.

Luis Lopez
Kurento.org Project Coordinator
+34 914 888 713 • lu...@kurento.com • prof.luis.lopez • • • •

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Best WoW Factor Award at WebRTC Conference & Expo 2014 (California)

Audience Choice Award at WebRTC Conference & Expo 2014 (California)

Best of Show Award at WebRTC conference expo 2014 (Paris)

[Victor Rotenberg]

Hello, David!

Did you solve the problem? I have exactly  the same.

Thanks.