VTX Control

Nebulus configures an existing OpenIPC air unit without changing its firmware. The implementation follows the WFB mode used by PixelPilot_rk:

Item	Value
Ground station address	10.5.0.1/24
VTX address	10.5.0.10
WFB tunnel downlink	radio port 0x20
WFB tunnel uplink	radio port 0xa0
SSH	TCP 22
Video-mode service	TCP 12355
Stock login	root / 12345

APFPV and aalink are deliberately outside this path. It needs no VTX firmware patch, proxy, WebSocket bridge, or internet connection.

Data Flow

openipc-core recovers the raw tunnel payload. openipc-uplink walks every two-byte big-endian length entry in the payload because wfb_tun may aggregate several IP packets, then passes those packets into smoltcp and exposes a Tokio AsyncRead + AsyncWrite stream. Browser and desktop builds use Russh 0.50 because its RustCrypto backend builds for wasm32-unknown-unknown. Android uses current Russh with Ring, avoiding a Linux-only errno call in Russh 0.50's memory-lock helper. Both are hidden behind the same SshClient API.

On native targets the SSH command executor runs separately from USB capture. On the web it runs as a local future. The receiver loop owns IP polling and WFB transmission on both, so a slow SSH command cannot block video capture. TCP retransmission recovers from a temporarily full radio TX queue.

Nebulus

1. Enable Setup → VTX → Enable VTX control before starting RX.
2. Start RX and wait for the radio link.
3. Open Setup → VTX, then select Connect or Refresh config.
4. Apply WFB, camera, telemetry, or adaptive-link settings.

Refresh config parses the known fields in the air unit's wfb.yaml and majestic.yaml into the controls. Unknown keys remain visible in the raw configuration snapshot and do not make refresh fail, which keeps the UI usable with custom and newer firmware files.

The controls map to the current firmware behavior:

Group	Firmware operation
WFB radio and broadcast	wifibroadcast cli -s, then one WFB restart per submitted batch
Camera and encoder	Majestic cli -s, then one killall -1 majestic per submitted batch
Simple video mode	text command to TCP 12355
Telemetry	serial console handling, wifibroadcast cli -s, GS render-route patch, then WFB restart
Adaptive link	/etc/alink.conf, /etc/txprofiles.conf, and alink_drone lifecycle
Config refresh	/etc/majestic.yaml, /etc/wfb.yaml, and optional adaptive-link files
System	VTX reboot

Nebulus asks for confirmation before RF and broadcast changes, video-mode or encoder changes, ISP/sensor changes, telemetry restarts, adaptive-link changes, TX-profile replacement, and reboot. Image controls and VTX recording settings remain immediate because they do not normally disconnect the radio link.

Changing WFB channel or width can immediately break the current link. Set the ground-station receiver profile to the same values before reconnecting.

The host-key field is optional for parity with PixelPilot's StrictHostKeyChecking=no. For a pinned installation, enter the complete SHA256:... fingerprint. A mismatch rejects the connection. Credentials are stored with local Nebulus settings and excluded from support bundles.

Library Use

The network is transport-neutral. Feed recovered tunnel payloads from any WFB receiver and transmit its output with any WFB-capable radio:

use openipc_uplink::{
    NetworkConfig, SshClient, SshCredentials, UserspaceNetwork, VtxController,
    WfbSetting,
};

let mut network = UserspaceNetwork::new(NetworkConfig::default())?;
let stream = network.connect_tcp(22)?;

// While this future runs, keep polling `network`, feed recovered port 0x20
// payloads with `ingest_tunnel_payload`, and transmit every `drain_outbound`
// item through WFB port 0xa0.
let ssh = SshClient::connect(stream, SshCredentials::default()).await?;
let controller = VtxController::new(ssh);
controller
    .set_wfb_batch(&[
        WfbSetting::McsIndex(1),
        WfbSetting::FecK(8),
        WfbSetting::FecN(12),
    ])
    .await?;
# Ok::<(), Box<dyn std::error::Error>>(())

UserspaceNetwork has no hidden thread and opens no platform socket. Applications choose their executor and polling cadence. Tests connect two smoltcp peers through OpenIPC tunnel framing and verify a TCP handshake plus bidirectional byte transfer without hardware.

Optional OS VPN

The TUN interface remains an additional native feature. Enabling it mirrors tunnel IP packets to the operating system, but internal VTX control does not depend on it. The same settings therefore work in a browser, where arbitrary TCP sockets and TUN devices are unavailable.