ChannelLab mesh video (Avalonia + Novolis libraries)

Policies that keep the org coherent

dotnetgovernancenovolis

name: ChannelLab mesh video overview: Add mesh video to ChannelLab with Avalonia-only UI and new Novolis media/RTC packages (SIPSorcery-backed). No WebView, HTML/JS, LiveKit, or Coturn. SignalR stays as the existing ChannelHost signaling plane. todos:

id: novolis-rtc-abs

content: Add Novolis.Media.Rtc.Abstractions (frames, IRtcMeshSession, signal DTOs) in novolis-audio status: completed

id: novolis-rtc-impl

content: Add Novolis.Media.Rtc (SIPSorcery mesh) + Novolis.Media.Capture.Windows (webcam) status: completed

id: avalonia-video-surface

content: Add Novolis.Avalonia.Media VideoSurface control (WriteableBitmap tiles) status: completed

id: hub-signal

content: Add ChannelHub.Signal + video membership (max 4) and SignalEnvelope DTO status: completed

id: channellab-wire

content: ChannelLab PeerWindow Video toggle + MeshSession wired to SignalR; no WebView status: completed

id: smoke-docs-gpr

content: ChannelSmoke signaling proof, README, Platform map regen; PackageReference 2026.1.* status: completed isProject: false

Approach (locked)

No WebView, no HTML/JS, no browser WebRTC. Media plane is native .NET + Avalonia controls. Missing platform pieces are new Novolis packages. ChannelHost SignalR remains the signaling bus (already in ChannelLab; not a browser UI).

Mesh: up to 4 peers in #lobby. No LiveKit / Coturn / SFU.

sequenceDiagram
  participant UI_A as PeerWindow_A
  participant Mesh_A as IRtcMeshSession_A
  participant Hub as ChannelHub
  participant Mesh_B as IRtcMeshSession_B
  participant UI_B as PeerWindow_B
  UI_A->>Hub: Signal video-join
  Hub->>UI_B: Signal video-join
  UI_B->>Mesh_B: AttachPeer alice
  Mesh_B->>UI_B: LocalSdp offer
  UI_B->>Hub: Signal offer toNick=alice
  Hub->>UI_A: Signal offer
  UI_A->>Mesh_A: ApplyRemote
  Mesh_A->>UI_A: LocalSdp answer
  UI_A->>Hub: Signal answer toNick=bob
  Hub->>UI_B: Signal answer
  Mesh_A-->>UI_A: OnRemoteFrame
  UI_A-->>UI_A: VideoSurface.Invalidate

Third-party (nuget.org only): SIPSorcery + SIPSorceryMedia.Windows (webcam / encode helpers). Wrapped behind Novolis abstractions so ChannelLab never talks to SIPSorcery types directly.

New Novolis packages

In [novolis-audio](d:\novolis\novolis-audio) (realtime media next to capture)

Package	Role
`Novolis.Media.Rtc.Abstractions`	`VideoFrame` (RGB24/BGRA + width/height/stride), `RtcSignalKind`, `RtcSignalMessage`, `IRtcMeshSession` (JoinVideo / PartVideo / HandleSignal / events for local signals + remote frames + peer list)
`Novolis.Media.Rtc`	SIPSorcery `RTCPeerConnection` mesh: polite peer = greater nick; max 4 peers; host provides signaling via callbacks (no HTTP/WebSocket inside the package)
`Novolis.Media.Capture.Windows`	Webcam (+ mic if trivial) implementing capture interfaces used by `Novolis.Media.Rtc` on Windows

Packable, 2026.1.*, regenerate Platform map via `Generate-Platform-Slnx.ps1`. Local dogfood builds with -p:NovolisUseProjectReferences=true until GPR publish.

In [novolis-avalonia](d:\novolis\novolis-avalonia)

Package	Role
`Novolis.Avalonia.Media`	`VideoSurface` — Avalonia control that accepts `VideoFrame` updates onto a `WriteableBitmap` (local preview + remote tiles). No web controls.

ChannelHost (signaling only)

In ChannelHub.cs + ChannelDirectory.cs:

DTO SignalEnvelope(channel, fromNick, kind, payload, toNick?).
Hub Signal(channel, kind, payload, toNick?): kinds video-join / video-part / offer / answer / ice; target nick or others-in-group; reject video-join at 4 video participants.
Clear video membership on disconnect / Part.
Text path unchanged.

ChannelLab client

ChannelSession.cs: SendSignalAsync + SignalReceived.
New MeshVideoController: owns IRtcMeshSession, maps SignalR ↔ session, pushes frames to VideoSurface instances.
PeerWindow.cs: Video toggle; strip of Avalonia VideoSurface tiles (local + remotes); chat layout unchanged; Video off or capture failure must not break Say/Join.
ControlWindow.cs: drop “video deferred” copy.
PackageReferences: Novolis.Media.Rtc, Novolis.Media.Capture.Windows, Novolis.Avalonia.Media (plus existing Identity / SignalR client).

Explicitly out: Avalonia.Controls.WebView, mesh.html / mesh.js, LiveKit, Coturn, browser getUserMedia.

Proof / docs / publish

ChannelSmoke: signaling-only (video-join + fake offer payload fan-out). No camera in CI.
Manual: two peer windows, Video on, local + remote tiles (Windows camera permission).
README: MediaSession = Avalonia + Novolis.Media.Rtc mesh; max 4; no SFU / no WebView.
After packages land: GPR publish from audio + avalonia; dogfooding stays PackageReference-only on main.

Constraints

Avalonia UI only for video presentation.
New capabilities live in Novolis packages, not ad-hoc SIPSorcery calls in the app.
No “bridge” wording in UI/docs.
Windows-first capture package; abstractions stay platform-neutral.