Why does frame loss occur?

[Charles Luo]

Hello.

I use the following way to live streaming.

OBS (Boardcaster) -> RTMP protocol -> Wowza -> RTP protocol -> Janus -> WebRTC -> browser (Viewer)

At present I encountered a issue that in the browser (Viewer) i get some frame loss, and then the video playback is not enough smooth.

According to Chrome debug tool data (chrome: / / webrtc-internals /), the googFrameRateDecoded and googFrameRateOutput is almost 30, but the googFrameRateReceived have a large fluctuations, always between 15 to 25.

Anyone have any advice on the issue?

[Lorenzo Miniero]

Loss can occur for different reasons, and in different parts of the delivery chain you mentioned. You should try capturing traffic and see if any packet is lost before it gets to Janus. If they're all there, loss may be occurring between Janus and the viewer, e.g., because of network issues, or because you're trying to send RTP packets that exceed the MTU and so are dropped.

L.

[Charles Luo]

Hello Lorenzo,

Thank you for reply.

As your advice, i use tcpdump tool  to grab the RTP packet in the Wowza server, and it seems like no packages is loss.

Do you have any advices on this point? 

>>According to Chrome debug tool data (chrome: / / webrtc-internals /), the googFrameRateDecoded and googFrameRateOutput is almost 30, but the googFrameRateReceived have a large fluctuations, always between 15 to 25.

googFrameRateDecoded 30

googFrameRateOutput 30

googFrameRateReceived 19

This is stats graphs for video. 

Thank you very much.

Best Regards

[Lorenzo Miniero]

Il giorno mercoledì 19 luglio 2017 10:28:14 UTC+2, Charles Luo ha scritto:

Hello Lorenzo,

Thank you for reply.

As your advice, i use tcpdump tool  to grab the RTP packet in the Wowza server, and it seems like no packages is loss.

I also mentioned packet loss between Janus and viewer, though. You should check the Admin API for information on that, as it will tell you some stats related to the WebRTC stuff for the viewers.

L.

[Charles Luo]

Hello Lorenzo,

Thank you for reply.

I want to check the Admin API, but i found the Admin API HTTP can't work. 

I get the next error log.

It seems like the MHD_start_daemon function can't work fine.

Do I missing some of my libraries, or some other reason?

============================================

[Wed Jul 19 18:46:57 2017] Using a thread per connection for the Janus API HTTP webserver

[Wed Jul 19 18:46:57 2017] Binding to all interfaces for the Janus API HTTP webserver

[Wed Jul 19 18:46:57 2017] [FATAL] [transports/janus_http.c:janus_http_init:724] Couldn't start webserver on port 8088...

[Wed Jul 19 18:46:57 2017] Using certificates:

/opt/janus/share/janus/certs/mycert.pem

/opt/janus/share/janus/certs/mycert.key

[Wed Jul 19 18:46:57 2017] [WARN] HTTPS webserver disabled

[Wed Jul 19 18:46:57 2017] Using a thread per connection for the Admin API HTTP webserver

[Wed Jul 19 18:46:57 2017] Binding to all interfaces for the Admin API HTTP webserver

[Wed Jul 19 18:46:57 2017] [FATAL] [transports/janus_http.c:janus_http_init:803] Couldn't start admin/monitor webserver on port 7088...

============================================