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Mandelbrot features

Mandelbrot keeps every Fractal feature and adds the ones below. Features marked experimental are new in Mandelbrot and still being validated against live homeservers — please file issues.

Synced from tuna-os/mandelbrot docs/FEATURES.md.

Native voice & video calls (experimental)​

Mandelbrot implements MatrixRTC calling natively — no embedded browser. The implementation lives in the mandelbrot-matrixrtc crate and follows the same semantics as Element Call (its conformance suite is ported from matrix-js-sdk: 114+ tests run in CI, plus a live interop harness under tests/e2e/).

Interop with Element Call is verified. Against Element Call v0.22.0 on a live stack, both clients write the same membership format, read each other, and connect calls in either direction, with crash cleanup working across implementations — see the conformance report in the repo (tests/e2e/CONFORMANCE.md) for the full details, including the two known gaps (media encryption with Element Call is expected to work but is not yet proven end to end, and Element Call's experimental MSC4354 "matrix 2.0" mode is not supported yet).

  • Join a call: rooms with an active call (or MSC3417 video rooms) show a camera button in the room header. It opens a pre-join screen (mic/camera toggles) and then the call view.

  • Call view: participant grid with speaking highlights, your own preview in the corner, auto-hiding controls (mute, camera, audio output, hang up). Closing the view keeps the call running; a compact call bar above the room timeline returns you to it.

  • Incoming calls: urgent system notifications with Accept/Decline, using the freedesktop notification portal v2 call.incoming category (fully supported on Phosh; GNOME Shell support is landing across releases — elsewhere they degrade to normal notifications with action buttons).

  • Encryption: calls are end-to-end encrypted. Per-participant media keys are distributed over Olm-encrypted to-device messages and rotated when someone leaves (grace periods prevent rotation storms on joins).

  • Reliability: if the app crashes or loses connection mid-call, an MSC4140 delayed event automatically removes your call membership after a short window, so you never appear stuck in a call.

  • Camera: the camera toggle captures your camera through the XDG camera portal (so it works in the Flatpak sandbox, and the camera is only opened while the toggle is on), and publishes it to the call. The same stream feeds the preview on the pre-join screen and the self-view during the call.

  • Requirements: the homeserver must advertise a LiveKit SFU (org.matrix.msc4143.rtc_foci in .well-known, e.g. matrix.org) and support MSC4140 delayed events (Synapse ≥ 1.114 with the feature enabled).

  • Spec surface: MSC4143 (MatrixRTC), MSC3401 (m.call.member), MSC4195 (LiveKit focus), MSC4140 (delayed events), MSC4075 (call notifications).

Simplified sliding sync (MSC4186)​

On homeservers that support it (Synapse ≥ 1.114 by default), Mandelbrot uses the SDK's SyncService — much faster initial sync and a room list that loads instantly. On servers without it, Mandelbrot automatically falls back to classic /sync (and even falls back at runtime if a proxy starts rejecting sliding sync mid-session). The active mode is logged at startup.

QR code login (MSC4108)​

Both directions, on OAuth 2.0 homeservers (matrix.org and anything running matrix-authentication-service):

  • Sign in with QR code (login screen): scan the code shown by your existing device, compare the two-digit check code, and the new session is set up with encryption transferred — no password typing.

  • Link another device (Account Settings → Sessions → "Link New Device…"): shows the QR code for another device to scan, with check-code confirmation.

Threads (MSC3440)​

  • Messages that start a thread show a "N replies in thread" button; it opens the thread in a side panel (an overlay on narrow windows).
  • The thread panel has its own composer — replies automatically carry the m.thread relation — plus thread-scoped reply, edit, reactions, and per-thread drafts.
  • "Reply in Thread" in any message's context menu starts a new thread.
  • Thread replies are hidden from the main timeline (Element-style).
  • Not yet: threaded read receipts (MSC3771); thread activity does not mark a room unread.

Polls (MSC3381)​

  • Create polls from the composer's attach menu: question, 2–20 answers, and a choice of showing results while the poll is ongoing (disclosed) or only at the end (undisclosed).

  • Vote by clicking an answer; disclosed polls show live counts and proportional bars after you vote; ended polls highlight the winning answer(s).

  • Poll creators (and moderators with redact power) can end a poll from the message context menu.

Voice messages (MSC3245)​

  • With an empty composer, press the microphone button to record (Ogg Opus, up to 30 minutes) with live elapsed time and level meter; send or cancel.

  • Sent messages carry the voice-message flag, duration, and waveform, so Element and other clients render them as voice messages. Playback of received voice messages was already supported.

Under the hood​

  • matrixrtc/ — the MatrixRTC engine crate (membership state machine, E2EE key distribution, call session, LiveKit connection behind the livekit feature). Its test suite is ported from matrix-js-sdk's matrixrtc suite and runs as the "MatrixRTC conformance tests" CI job.

  • tests/e2e/ — a podman-compose interop harness (synapse + LiveKit + lk-jwt-service) that runs real calls between clients; see its README.

  • Media (calls-media cargo feature / -Dcalls-media meson option) links LiveKit's Rust SDK with a statically-built libwebrtc; the default build stays lean without it. Flatpak builds enable it.