* ref(SDPDiffer) Convert to ES6 class.
Make it work directly with unified plan SDP that has multiple m-lines and add more unit tests.

* ref(xmpp) translate unified-plan SDP->Jingle directly.
Without having to run it through the SDPInterop.toPlanB cycle.

* ref(SDP) Always generate the MSID for signaling it to Jicofo.

* fix(SDPDiffer) Check explicitly for ssrc changes

* fix(SDP): Fix comments and cleanup.
Remove LOCAL_TRACK_SSRC_UPDATED event as the application ignores the event and no additional action needs to be taken when that event is fired.

* ref(SDP) Add a helper function for parsing the 'a=ssrc-group' line.

* squash: Address review comments

This was needed in older versions since the browser didn't apply maxBitrates from RTCRtpEncoderParameters on the encoder. In the newer versions this seems to be no longer the case. Also, when the codec selection API is used, we no longer renegotiate locally so if we switched codec from AV1->VP9-VP9, the AV1 bitrate setting in the SDP will still be effective resulting in a lower send resolution because of b/w limitation.

* ref(QualityController) Add recovery mechanism and adjust the resolution check.
Impl a recovery mechanism for the lastN to be increased if the cpu limitation goes away and doesn't return after increasing lastN. Also, additionally improve the calculation of the expected resolution taking simulcast stream resolutions into account.

* squash: Address review comments and add more unit tests

* squash: Address review comments

* feat(quality) Add a QualityController class for runtime adjustments.
Make run time adjustments to the client when adaptive mode is enabled.

* feat: Update lastN and receive resolution to improve quality.

* squash: Address review comments

* squash: Add more logging and address review comments.

* feat(codec-selection): Use the new codec selection API
https://github.com/w3ctag/design-reviews/issues/836. This allows the client to seamlessly switch between the codecs without having to trigger a renegotiation.
This feature is behind the flag testing.enableCodecSelectionAPI in config.js

* fix(stats): Fix local resolution stats.
The video codec for the local video sources needs to identified differently now, from the codecs field in the RTCRtpSendParameters returned by the browser. We no longer munge the remote SDP to switch to a different codec.

* feat(stats): Feed encodeTime stats for all local SSRCs to the codec selection mechanism.

* fix(codec-selection) Continue to mumge SDP for selecting H.264.

* feat(codec-selection) Make screenshare codec configurable.
If no 'screenshareCodec' is set under videoQuality or p2p settings, AV1 will be selected as default.

* squash: Address review comments

* Update modules/RTC/CodecSelection.js

Co-authored-by: Saúl Ibarra Corretgé <s@saghul.net>

* fix(codec-selection) Add codec to existing stats

---------

Co-authored-by: Saúl Ibarra Corretgé <s@saghul.net>

Fixes poor low resolution video from Spot running older electron versions when the codec changes from VP9->VP8->VP9.

This helps us in identifying the video codec associated with a local video track for codec selection torture tests.

Fixes an issues where microphone change for Safari fails.

When an existing SSRC for a remote track gets re-mapped from one source to another, fire a TRACK_REMOVED event followed by TRACK_ADDED event instead of TRACK_OWNER_CHANGED event. This should simplify the application logic for track handling.

This is needed when p2p conn establishes before jvb and no sender constraints have been received before media on jvb conn is suspended.

Also fixes the issue with video freezing after video mute and unmute when the user joins the call with startSilent=true.

Check if all the relevant fields are correctly configured instead of checking for just the encode resolution on the local video sender.

Chrome on macOS recently started offering encoder for higher level (5.2) but decoder only for level 3.1. See https://issues.chromium.org/issues/324930413
Therefore, filter out all H.264 payload types with main and high profiles. Also, sort all H.264 payload types so that same pt is picked for both H.264 encoder and decoder. Fixes random black tile issues across different browsers when H.264 is the preferred codec for p2p.

We do not want non Chromium browsers to negotiate DD ext headers when VP8/VP9 is the selected codec. Fixes poor video quality issue for Safari when Av1 is offered by Jicofo.

Require cycle: lib/lib-jitsi-meet/modules/RTC/RTC.js -> lib/lib-jitsi-meet/modules/RTC/TraceablePeerConnection.js -> lib/lib-jitsi-meet/modules/RTC/RTC.js

Set the scalabilityMode to undefined for VP8 after a VP9->VP8 switch even though the browser returns L1T2 in the RTCRtpSender.getParameters() call. Fixes an issue where the bridge stops forwarding video for some participants after vp8->vp9 switch.

The browser returns height as 0 at track creation time. Fixes an issue where Safari's screenshare shows as black.

Check the first payload type of the m-line in remote description to get the codec used for encoding the local video source.

Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1877675.

If MediaStreamTrack.getSettings() doesn't return the height of the track, use the constraints passed to gUM for calculating the height. Fixes an issue for Firefox/Linux which could result in media not displayed.

When a local video track is muted, getSettings() on MediaStreamTrack doesn't return capture height. Fixes random torture test failures on beta.

* fix(video-quality): Adjust encodings bitrates/scalefactor for high capture resolutions.
When the client is configured to capture camera sources at 1080p or higher, adjust the bitrates and the encodings scale factor accordingly.

* squash: Address review comments
Fix the bitrates set on the remote description and also bump up the bitrates for 1080p, 4k and screenshare.

* squash: Address some more review comments.

This check is not needed anymore since we now set the correct scaleResolutionDownBy value everytime the encodings are configured. Fixes a regression on Safari where it can end up sending low resolution to a p2p peer in some cases. Also, add more unit tests for p2p desktop share cases.

* fix(RTC): Remove support for plan-b SDP.
Since unified plan mode becomes the default mode, so does multi-stream mode.

* squash: Remove plan-b unit tests and fix comments

* squash: address review comments

When these are configured, the browser sends only the lowest resolution layer even when all the encodings are active. Fixes a quality issue on older versions of Chromium that do not support the scalabilityMode API.

There is a lot of additional noise when log level is set to debug, the SDP descriptions should be set to trace (As it seems it was originally intended, based on the name of the variable)

This fixes an issue when encodings for video streams are configured incorrectly after every codec switch

Add SVC and Simulcast support for AV1 and VP9.

The default mode is the full SVC mode for VP9. It works as expected with the current version of JVB.
AV1 in the client is only supported when the bridge negotiates the Dependency Descriptor extension headers which are needed for reading the layer information for AV1 and H.264 video frames.

* feat: Enable H.264 simulcast support.
Multi-encoding simulcast for H.264 is supported now because of the DD header ext support added on the bridge side.

* fix(video-quality): Add default bitrates for all codecs.
Expect the videoQuality settings in the new format, deprecated configs are still supported.
videoQuality: {
    AV1: {
        maxBitratesVideo: {
            low: 100000,
            standard: 300000,
            high: 1000000,
            ssHigh: 1500000
        },
        useScalabilityModeAPI: {
            enabled: true,
            useSimulcast: true, //(defaults to SVC),
            useKSVC: true //(defaults to L3T3_KEY)
        },
    },
    H264: {
        maxBitratesVideo: {
            low: 200000,
            standard: 500000,
            high: 1500000,
            ssHigh: 2500000
        }
    },
    VP8: {
        maxBitratesVideo: {
            low: 200000,
            standard: 500000,
            high: 1500000,
            ssHigh: 2500000
        }
    },
    VP9: {
        maxBitratesVideo: {
            low: 100000,
            standard: 300000,
            high: 1200000,
            ssHigh: 2500000
        },
        useScalabilityModeAPI: {
            enabled: true,
            useSimulcast: true, //(defaults to SVC),
            useKSVC: true //(defaults to L3T3_KEY)
        },
    }
}

* Disable encodings when requested height for screenshare is 0.

* feat: add unit tests for scalability modes.

* ref: Move all encoding configuration calculation to TPCUtils.

* Add more unit tests for VP9 K-SVC mode.

* Make codec name in settings case insensitive.
Also read the deprecated max bitrates correctly, add unit tests to test it.

* ref(TPC): isSimulcastOn -> isSpatialScalabilityOn.
It makes more sense to call it spatial scalability than simulcast now that full SVC support is available.

* fix: Negotiate AV1 DD header exts only for AV1 and H.264.

* fix: Rename setting useL3T3Mode->useKSVC and adjust the defaults.

More than one VP9 payload type is produced in the offer, more experimental ones if the local endpoint has no local video source. Munge the SDP to remove all codecs besides the one with profile-id=0 so that only one VP9 codec is negotiated with p2p peer.

Recommit 17ade96a70 with the jvb leak fix.

This is much faster than changing direction on the transceiver and doesn't need a renegotiation for the suspending/resuming media. Also fixes an issue with audio-only mode in p2p where media doesn't resume when audio-only mode is disabled if it was enabled while the jvb connection was active.

For renegotiations triggered by the application, it is ok to execute sRD->cA-sLD cycle on the p2p initiator instead of executing cO->sLD->sRD cycle. Chrome sometimes creates a third m-line for p2p when createOffer is called which is unexpected and therefore it breaks the client's renegotiation cycle. This has been done in other places already, i.e., when remote sources are signaled, etc. so making it uniform across all renegotiations.

Just moving them to the end of the list guarantees that they are not picked for encoding.

This reverts commit 17ade96a70.

It causes setParameters failures which can cause media being leaved to
JVB when in a P2P connection.

* fix(codec-selection) Use a configurable preferred codecs list to select the codecs.
Allow asymmetric codecs to be configured on the endpoints. This means that Firefox and Safari which have bugs with VP9 encode will now encode VP8 but decode VP9 coming in from Chromium endpoints.

* fix(codec-selection) Add unit tests for the codec selection logic.

* feat(codec-selection): Introduce mobileCodecPreferenceOrder setting in config.js.

* fix(codec-selection) Avoid unnecessary renegotiations.
On participant join/leave, check if the new intersection of codecs are already configured to be the top n codecs.

* Address review comments

* fix: Strip the codecs that are not in the codec list from the video m-lines.
Also, ignore remote codecs published in presence for p2p connections.

* fix: Define default codec order for mobile and desktop.
Fix an issue where p2p between mobile and desktop was broken.

* fix: Add default codecs for both p2p and jvb on mobile devices.
Munge the initial offer sent out by RN clients since RN doesn't support RTCRtpTransceiver#setCodecPreferences.