Integrating venc with WFB-ng

This guide describes how to fully replace Majestic with waybeam venc in combination with WFB-ng (WiFi Broadcast) for low-latency FPV streaming.

System architecture

┌─────────────────── CAMERA (VTX) ───────────────────┐
                                                      
  Sensor → ISP → venc (H.265 encoder)                
                    │                                  
                    ├─ RTP over a Unix socket          
                    ▼                                  
              wfb_tx (WFB-ng TX)                      
                    │                                  
                    ▼                                  
              WiFi adapter (RTL8812EU / AU)            
└──────────────────────────────────────────────────────┘
                     │  (radio link)
                     ▼
┌──────────── GROUND STATION (GS) ────────────────────┐
              WiFi adapter (RTL8812EU / AU)            
                    │                                  
                    ▼                                  
              wfb_rx (WFB-ng RX)                      
                    │                                  
                    ├─ UDP → PixelPilot / QGroundControl
                    ▼                                  
         Video player (port 5600)                      
└──────────────────────────────────────────────────────┘

Part 1: Camera (VTX) setup

1.1 Prerequisites

Before you start, make sure that:

✅ OpenIPC firmware is installed on the camera
✅ WFB-ng (wfb_tx) is installed and running
✅ A WiFi adapter (RTL8812EU or RTL8812AU) is connected
✅ You have SSH access to the camera

Installing venc

If venc is not yet installed, see Installing venc on the camera.

1.2 Stop Majestic

bash

# Stop Majestic
killall majestic 2>/dev/null

# Disable autostart (if using init.d)
chmod -x /etc/init.d/S95majestic 2>/dev/null

1.3 Configuring venc for WFB-ng

The main difference from Majestic is how the video is delivered to WFB-ng.

Method 1: Unix socket (recommended)

The most efficient method is transmission over an abstract Unix socket. This reduces latency compared to UDP, since the data doesn't go through the kernel's network stack.

Edit /etc/venc.json:

json

{
  "outgoing": {
    "enabled": true,
    "server": "unix://wfb_tx",
    "streamMode": "rtp",
    "maxPayloadSize": 1400,
    "connectedUdp": true,
    "audioPort": 0,
    "sidecarPort": 0
  }
}

Socket name

The name wfb_tx in unix://wfb_tx is the name of the abstract Unix socket. It must match the WFB-ng configuration on the transmitter side. Check the WFB-ng configuration to make sure wfb_tx is listening on this socket.

Method 2: UDP on localhost

If WFB-ng expects an RTP stream over UDP:

json

{
  "outgoing": {
    "enabled": true,
    "server": "udp://127.0.0.1:5600",
    "streamMode": "rtp",
    "maxPayloadSize": 1400,
    "connectedUdp": true,
    "audioPort": 0,
    "sidecarPort": 0
  }
}

Method 3: Shared Memory (SHM)

For maximum performance — via a ring buffer in shared memory:

json

{
  "outgoing": {
    "enabled": true,
    "server": "shm://venc_ring",
    "streamMode": "rtp",
    "maxPayloadSize": 1400,
    "connectedUdp": true,
    "audioPort": 0,
    "sidecarPort": 0
  }
}

SHM and audio

shm:// works only in RTP mode.

**Audio is not supported over the main SHM channel even with `audioPort: 0`.**
If you need audio with `shm://` — set `audioPort > 0` (e.g. `5601`), and audio will go to a separate UDP port.

1.4 Configuring WFB-ng on the camera

The WFB-ng configuration must match the transmission method you chose in venc.

For the Unix socket — in the wfb_tx configuration, specify the same abstract socket:

# In the wfb_tx configuration
# Input stream — from the Unix socket from venc
peer = listen://unix://wfb_tx

For UDP on localhost:

# In the wfb_tx configuration
# Input stream — UDP from venc
peer = listen://udp://127.0.0.1:5600

1.5 Optimal video parameters for WFB-ng

Recommended parameters for stable FPV streaming over WiFi Broadcast:

json

{
  "video0": {
    "codec": "h265",
    "rcMode": "cbr",
    "fps": 60,
    "size": "1920x1080",
    "bitrate": 8192,
    "gopSize": 1.0,
    "qpDelta": -4,
    "frameLost": true,
    "sceneThreshold": 0,
    "sceneHoldoff": 2
  }
}

Parameter explanation:

Parameter	Recommendation	Why
`codec: "h265"`	H.265	Better quality at the same bitrate; required for RTP on Star6E
`rcMode: "cbr"`	CBR	A stable bitrate is better for the radio link
`fps: 60`	60 fps	Balance between smoothness and load
`bitrate: 8192`	8 Mbit/s	Optimal for a 20 MHz WFB channel
`gopSize: 1.0`	1 second	Fast recovery after packet loss
`frameLost: true`	Enabled	Allows frames to be dropped when overloaded

Bitrate and channel width

Match the bitrate to the WFB-ng throughput:

| Channel width | MCS | Max. bitrate | Recommended |
| :--- | :--- | :--- | :--- |
| 20 MHz | MCS 3 | ~20 Mbit/s | 8–12 Mbit/s |
| 20 MHz | MCS 1 | ~10 Mbit/s | 4–6 Mbit/s |
| 40 MHz | MCS 3 | ~40 Mbit/s | 16–22 Mbit/s |

1.6 Service startup order

The correct startup order on the camera:

bash

# 1. Load the WiFi driver
insmod /lib/modules/88XXau.ko 2>/dev/null

# 2. Start WFB-ng TX
wfb_tx -u unix://wfb_tx -p 0 -k 8 -n 12 wlan0 &

# 3. Start venc
venc &

Init script

For automatic startup, create an init script as described in Install on the camera — Step 7. Make sure the script numbers are in the right order: WiFi → WFB-ng → venc.

Part 2: Ground station (GS) setup

2.1 Ground station requirements

Component	Options
Platform	Radxa Zero 3W, Raspberry Pi 4/5, x86 Linux
WiFi adapter	RTL8812EU (recommended) or RTL8812AU
Player	PixelPilot (Android), QGroundControl, ffplay

2.2 Configuring WFB-ng RX

On the ground station, WFB-ng receives the stream and outputs it to a UDP port for the player:

bash

# Start the WFB-ng receiver
wfb_rx -p 0 -c 127.0.0.1 -u 5600 -k 8 -n 12 wlan0

The parameters must match the TX settings on the camera:

Parameter	TX (camera)	RX (ground)	Description
`-k`	`8`	`8`	FEC data blocks
`-n`	`12`	`12`	Total FEC blocks
`-p`	`0`	`0`	WFB port (channel)

2.3 Watching the video

PixelPilot (Android)

Connect the ground station to the phone
Open PixelPilot
Set the RTP source: udp://0.0.0.0:5600

ffplay (Linux / Mac)

bash

ffplay -fflags nobuffer -flags low_delay -framedrop \
  -analyzeduration 0 -probesize 32 \
  -i udp://0.0.0.0:5600

QGroundControl

Open Settings → Video
Set "Video Source": UDP h.265 Video Stream
Port: 5600

GStreamer

bash

gst-launch-1.0 udpsrc port=5600 \
  caps="application/x-rtp,media=video,encoding-name=H265" ! \
  rtph265depay ! h265parse ! avdec_h265 ! autovideosink sync=false

Part 3: Audio over WFB-ng

venc supports transmitting audio in parallel with video:

3.1 Enabling audio on the camera

Update /etc/venc.json:

json

{
  "audio": {
    "enabled": true,
    "sampleRate": 16000,
    "channels": 1,
    "codec": "g711a",
    "volume": 80,
    "mute": false
  },
  "outgoing": {
    "audioPort": 5601
  }
}

Audio and the Unix socket

When using unix:// with audioPort: 0, audio is transmitted together with the video over the same socket. With audioPort > 0, audio is sent to a separate UDP port 127.0.0.1:<audioPort>.

3.2 Receiving audio on the ground station

bash

# Separate WFB channel for audio
wfb_rx -p 1 -c 127.0.0.1 -u 5601 -k 4 -n 8 wlan0

# Playback
ffplay -nodisp -fflags nobuffer -i udp://0.0.0.0:5601

Part 4: Adaptive control (advanced)

4.1 Scene-Change IDR

To improve stream recovery on abrupt scene changes (takeoff, maneuvers):

bash

# Enable scene detection (Star6E only)
curl "http://localhost/api/v1/set?video0.sceneThreshold=150"
curl "http://localhost/api/v1/set?video0.sceneHoldoff=2"

sceneThreshold: 150 — triggers at a ≈1.5x jump in frame size
sceneHoldoff: 2 — minimum interval between IDR frames

4.2 Sidecar for an external controller

If you use an external link-quality controller (adaptive link):

bash

curl "http://localhost/api/v1/set?outgoing.sidecarPort=6666"

The sidecar sends per-frame telemetry: frame_type, complexity, scene_change, idr_inserted, frames_since_idr.

Part 5: Recording to the SD card

venc supports simultaneous streaming and recording:

bash

# Enable recording via the API
curl "http://localhost/api/v1/record/start"

# Check the status
curl "http://localhost/api/v1/record/status"

# Stop recording
curl "http://localhost/api/v1/record/stop"

Gemini mode — stream to WFB-ng at a low bitrate while recording to SD at high quality:

json

{
  "record": {
    "enabled": true,
    "mode": "dual",
    "dir": "/mnt/mmcblk0p1",
    "format": "ts",
    "bitrate": 20000,
    "fps": 120,
    "gopSize": 2
  }
}

INFO

The MPEG-TS format doesn't need file finalization. Even on a sudden power loss, the recording will be readable up to the last written packet.

Verifying the integration

After configuration, run the checks:

bash

# 1. On the camera — verify that venc is streaming
curl http://localhost/api/v1/config | grep -A5 outgoing

# 2. On the camera — check the FPS
curl http://localhost/api/v1/version

# 3. On the ground station — check reception
# (should show video without significant latency)
ffplay -fflags nobuffer -i udp://0.0.0.0:5600

# 4. Request an IDR keyframe to start decoding
curl http://192.168.1.10/request/idr

Comparison: venc + WFB-ng vs Majestic + WFB-ng

Aspect	venc + WFB-ng	Majestic + WFB-ng
Latency	Lower (Unix socket / SHM)	UDP through the network stack
API	84 parameters in real time	Limited set
Recording	Gemini mode (stream + record)	Basic
ISP tuning	60+ parameters + export/import	Limited
EIS	GyroGlide-Lite (Star6E)	None
Web panel	Built-in with full control	—
Source	Open (MIT)	Closed

Next steps

Web panel and HTTP API — control via the browser
waybeam venc overview — all features
Install on the camera — initial installation

Integrating venc with WFB-ng ​

System architecture ​

Part 1: Camera (VTX) setup ​

Part 2: Ground station (GS) setup ​

Part 3: Audio over WFB-ng ​

3.1 Enabling audio on the camera ​

Part 4: Adaptive control (advanced) ​

Part 5: Recording to the SD card ​

Verifying the integration ​

Comparison: venc + WFB-ng vs Majestic + WFB-ng ​

Next steps ​

Integrating venc with WFB-ng

System architecture

Part 1: Camera (VTX) setup

Part 2: Ground station (GS) setup

Part 3: Audio over WFB-ng

3.1 Enabling audio on the camera

Part 4: Adaptive control (advanced)

Part 5: Recording to the SD card

Verifying the integration

Comparison: venc + WFB-ng vs Majestic + WFB-ng

Next steps