Screen sharing quality

neogeo

Member
Screen sharing quality is very bad most of the times. There are a few times that things look crisp and good for a few seconds but then it is all blurry again.

We use chrome and all the latest examples and WCS server. We have also added the googCpuOveruseDetection: false parameter.
The CPU utilization on the broadcaster is low, around 20-25% on a quad core i7 and there is no bandwidth issue between the server and broadcaster.
What I have noticed is that most of the times the bandwidth usage on the broadcaster is 100-400kbps and at that times the screen share looks very blurry. Then all of a sudden without any movement on the screen the bandwidth usage spikes to 1.5-2Mbit and then the screen share looks crisp.

Are there any other parameters that I can bypass in order to make it look better?

upload_2017-3-20_17-59-11.png
 

Max

Administrator
Staff member
With latest builds try to add
Code:
webrtc_cc2_cc=false
into WCS_HOME/flashphoner.properties
This setting requires WCS restart
Code:
service webcallserver restart
Then please share your chrome://webrtc-internals graphs
 

neogeo

Member
I am not sure if that setting affected anything.

There are times that screen looks very good but when there is motion then it becomes very blurry. It feels to me that the problem is the encoding that chrome does but I do not have any solid evidence.

upload_2017-3-20_22-8-31.png
 

Max

Administrator
Staff member
Try the following settings
Code:
webrtc_cc2=false
codecs=opus,alaw,ulaw,g729,speex16,g722,mpeg4-generic,telephone-event,vp8,h264,flv,mpv
Note, vp8 codec is in priority here.
We have tested on our server. 720p quality looks good.
quality.png
 

neogeo

Member
The codes ordering fixed it, tt is perfect now. On the default config it was h264,vp8. Should I expect any side effects on any other browser by having vp8 before h264?
 

Max

Administrator
Staff member
H.264 has better compatibility in integration with other systems and has hardware acceleration on some mobile devices.
It ensures less bandwidth and less encoding bitrate. This is a side effect.
Anyway we have to check why it does not work properly with H.264, because streaming from webcam does not have such issue with H.264.
I will inform you if we have any updates related this issue.
 
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