Clarification on options for optimal configuration for quality video

Install & Config
#1

On a self hosted Debian 10 Jitsi server (behind NAT firewall), when I check the participants video, I notice “send max 360p”, and “Codecs (A/V): optus, VP8”.

I would like to achieve full screen video of 1080p, if this is possible, but if the user is only sending 360p, I guess this will not happen. Is it possible to send greater than 360p and how would this be achieved?

Can someone please explain in more detail in greater detail than is in the configuration file, for the following options and how these can be changed and how they alter the video which participants send/receive:

disableSimulcast

enableLayerSuspension

maxBitratesVideo

minHeightForQualityLvl

videoQuality [settings]

disabledCodec

preferredCodec: ‘VP9’, (so far I have been unable to get VP9 to be used)

maxBitratesVideo

For example:

// Sets the preferred resolution (height) for local video. Defaults to 720.
resolution: 720,
// resolution of 720p.
constraints: {
     video: {
         height: {
             ideal: 720,
             max: 1080,
             min: 240
         }
     }
},

disableSimulcast: true,
enableLayerSuspension: true,

// Specify the settings for video quality optimizations on the client.
videoQuality: {
disabledCodec: ‘H264’,
preferredCodec: ‘VP9’,
maxBitratesVideo: {
low: 200000,
standard: 500000,
high: 1500000
},
minHeightForQualityLvl: {
360: ‘standard’,
720: ‘high’
},
},

Difference between Server side video constraints and end-user video quality
#2

I wonder why it is that I can only get good clear HD video (1280x720 or 970x720) when I have:

    disableSimulcast: true,
    enableLayerSuspension: true,

Even LD video seems to be better when “disableSimulcast: true” is set.

Note: I have learned that VP9 is still in development and therefore not available in the production version, so now I am now leaving the preferredCodec value to its default.

Why is it that disabling Simulcast actually improves video quality?

#3

These are my current video setting which seem to give the best video quality:

    resolution: 1080,
    maxFullResolutionParticipants: 20,
    constraints: {
         video: {
             height: {
                 ideal: 720,
                 max: 1080,
                 min: 240
             }
         }
    },
    disableSimulcast: true,
    enableLayerSuspension: true,
    channelLastN: -1,
    videoQuality: {
       maxBitratesVideo: {
            low: 200000,
            standard: 500000,
            high: 1500000
        },
        minHeightForQualityLvl: {
            360: 'standard',
            720: 'high'
        },
    },
#4

After re-reading the below statement:

// Sets the preferred resolution (height) for local video. Defaults to 720.
 resolution: 1080,

I am guessing that “resolution” does not change the quality of the video a participant sends to the other participants, but only affects their own view of themselves? Maybe a setting of 360p would be better for participant’s with older computer hardware?

And therefore setting to 1080 would only increase the load on their own CPU/web browser. Would this be true?