Video Input Connector

Publish camera frames to MQTT

Video Input opens a camera, network stream, or file on the broker host and publishes each frame as a JPEG data-URI. Dashboards and Coreflux HUB can drop that payload straight into an image tag. You start and stop capture with MQTT events.

Like a photo booth on a timer. You press start, and a new picture lands on the topic at the rate you chose — not a video file, a series of JPEGs.

When to use this

Use TYPE VIDEO_INPUT when a dashboard, barcode decode, or action needs still frames from a local camera, an RTSP or HTTP(S) camera, or a video file. FFmpeg must be on the broker host (or in the slim image). The connector does not talk to camera drivers itself.

Do not set WITH FORMAT. That keyword belongs to models. Every frame this connector publishes is a JPEG data-URI (data:image/jpeg;base64,…).

Pick the source that matches the camera. Each tab is a full connector: a config block plus start and stop events.

Quick Start

IP camera
Local camera
Windows camera
File

Store the RTSP URL in an environment variable so the password never sits in LoT:

DEFINE ROUTE EntranceCamera WITH TYPE VIDEO_INPUT
    ADD VIDEO_INPUT_CONFIG
        WITH SOURCE GET ENV "CAMERA_RTSP_URL"
        WITH FRAME_RATE "10"
        WITH WIDTH "640"
        WITH HEIGHT "480"
        WITH QUALITY "5"
        WITH DESTINATION_TOPIC "video/entrance/frames"
    ADD EVENT StartCapture
        WITH QUERY "START"
        WITH SOURCE_TOPIC "video/entrance/control/start"
    ADD EVENT StopCapture
        WITH QUERY "STOP"
        WITH SOURCE_TOPIC "video/entrance/control/stop"

On macOS and Linux, webcam:0 is the first camera. On Linux that is /dev/video0:

DEFINE ROUTE LocalCamera WITH TYPE VIDEO_INPUT
    ADD VIDEO_INPUT_CONFIG
        WITH SOURCE "webcam:0"
        WITH FRAME_RATE "5"
        WITH WIDTH "640"
        WITH HEIGHT "480"
        WITH QUALITY "5"
        WITH DESTINATION_TOPIC "video/local/frames"
    ADD EVENT StartCapture
        WITH QUERY "START"
        WITH SOURCE_TOPIC "video/local/control/start"
    ADD EVENT StopCapture
        WITH QUERY "STOP"
        WITH SOURCE_TOPIC "video/local/control/stop"
    ADD EVENT TakeSnapshot
        WITH QUERY "CAPTURE 1 FRAME"
        WITH SOURCE_TOPIC "video/local/control/snapshot"
        WITH DESTINATION_TOPIC "video/local/picture"

Copy the video device name from the DirectShow list. The video= prefix is required:

DEFINE ROUTE WindowsCamera WITH TYPE VIDEO_INPUT
    ADD VIDEO_INPUT_CONFIG
        WITH SOURCE "video=Integrated Webcam"
        WITH FRAME_RATE "5"
        WITH WIDTH "640"
        WITH HEIGHT "480"
        WITH QUALITY "5"
        WITH DESTINATION_TOPIC "video/windows/frames"
    ADD EVENT StartCapture
        WITH QUERY "START"
        WITH SOURCE_TOPIC "video/windows/control/start"
    ADD EVENT StopCapture
        WITH QUERY "STOP"
        WITH SOURCE_TOPIC "video/windows/control/stop"

Play a file on the broker host. On Windows, use a path FFmpeg accepts, such as C:/media/sample.mp4:

DEFINE ROUTE FileCamera WITH TYPE VIDEO_INPUT
    ADD VIDEO_INPUT_CONFIG
        WITH SOURCE "/var/media/sample.mp4"
        WITH FRAME_RATE "5"
        WITH DESTINATION_TOPIC "video/file/frames"
    ADD EVENT StartCapture
        WITH QUERY "START"
        WITH SOURCE_TOPIC "video/file/control/start"
    ADD EVENT StopCapture
        WITH QUERY "STOP"
        WITH SOURCE_TOPIC "video/file/control/stop"

Publish any payload to the start topic to begin. Frames then arrive on DESTINATION_TOPIC until you publish to the stop topic.

Configuration

string

required

Camera, URL, or file. webcam:N on macOS and Linux. video=Device Name on Windows. An rtsp://, http://, or https:// URL, or a file path, on any host. Prefer GET ENV or GET SECRET when the URL contains a password.

string

MQTT topic for JPEG frames. A START event uses this topic. A CAPTURE event can override it.

string

How many frames to publish per second, from 1 to 60. On a local camera this is the publish rate. Many cameras only capture at 15 or 30 fps in hardware; 5 still works as the rate on the topic.

string

Output width in pixels. Set it together with HEIGHT.

string

Output height in pixels. Set it together with WIDTH.

string

JPEG quantizer from 1 to 31. Lower numbers keep more detail and publish larger payloads. 5 is a balanced start. This is not a 1–100 percentage.

WIDTH, HEIGHT, and QUALITY apply to the JPEG on MQTT. They do not reconfigure the camera’s own encoder. Broker logs redact user:pass@ in RTSP and HTTP URLs. HTTP(S) sources use a 10 second timeout and the user-agent CorefluxVideoInput/1.0. RTSP uses TCP with the same timeout.

Capture sources

`SOURCE`	Broker host	What opens
`webcam:0`	macOS	First camera in the system list (built-in on many Macs)
`webcam:1`	macOS	Second camera, often USB
`webcam:0`	Linux	`/dev/video0`
`video=Integrated Webcam`	Windows	DirectShow device. The name must match exactly
`rtsp://…`, `http://…`, `https://…`	Any	Network stream. One attempt, no local-camera retry
File path	Any	File input

webcam:N is rejected on Windows. Device indexes are not stable in DirectShow, so use video= plus the exact name. A raw /dev/video0, or a Windows name without video=, is treated as a file path and skips the local-camera retries. On start, a local camera tries several input profiles until one stays open. Network URLs and files are a single attempt.

List devices on the broker host

Host	Command
Linux	`ls -l /dev/video*` — `webcam:0` is `/dev/video0`
macOS	`ffmpeg -f avfoundation -list_devices true -i ""`
Windows	`ffmpeg -list_devices true -f dshow -i dummy` — copy the video name into `video=…`

If macOS capture fails immediately, allow Camera access for the process that started the broker.

Events

string

required

START, STOP, CAPTURE <N> FRAMES, CAPTURE <N> SECONDS, or CAPTURE <N> MINUTES. CAPTURE 1 and CAPTURE 1 FRAME take one picture.

string

required

Topic that runs the event. Keep control topics separate from the frame topic.

string

Override for a snapshot or a timed clip. Continuous START uses the topic on VIDEO_INPUT_CONFIG.

Query	Result
`START`	Capture until `STOP`
`STOP`	Stop every capture on this connector
`CAPTURE 1 FRAME`	One JPEG
`CAPTURE <N> FRAMES`	That many frames
`CAPTURE <N> SECONDS`	Frames for N seconds
`CAPTURE <N> MINUTES`	Frames for N minutes

There is no motion or per-frame callback on the connector. Every decoded frame goes to DESTINATION_TOPIC. Failures show up in the broker log and on $SYS/Coreflux/Routes/{RouteName}/status. You can also publish -checkRouteConnection <RouteName> to $SYS/Coreflux/Command. An action can start a named event without a control publish:

DEFINE ACTION StartEntranceCamera
ON TOPIC "control/video/start" DO
    TRIGGER "EntranceCamera" TO PAYLOAD FOR "StartCapture"

Docker and FFmpeg

Install FFmpeg on the broker host and confirm ffmpeg -version there. The slim broker image includes FFmpeg on amd64 and arm64. The minimal image does not, and arm/v7 does not. RTSP and HTTP work in Docker with no camera hardware. A local camera needs the device node inside the container.

Where the broker runs	Local camera	Without a device mount
Linux container	Pass `--device /dev/video0` (or the matching node). Inside the image, `webcam:0` is `/dev/video0`	RTSP, HTTP, or a file
macOS or Windows Docker Desktop	The camera stays on the desktop host, not in the Linux VM	RTSP, HTTP, or a file

Payload size

JPEG on MQTT is much larger than sensor telemetry. Start at 5 fps, 640×480, and QUALITY 5. If subscribers or the HUB fall behind, lower FRAME_RATE or raise QUALITY (a larger quantizer) before you increase width and height. For a live camera, shed frames instead of blocking publishers:

DEFINE ROUTE EntranceCamera WITH TYPE VIDEO_INPUT
    ADD VIDEO_INPUT_CONFIG
        WITH SOURCE GET ENV "CAMERA_RTSP_URL"
        WITH FRAME_RATE "5"
        WITH WIDTH "640"
        WITH HEIGHT "480"
        WITH QUALITY "5"
        WITH DESTINATION_TOPIC "video/entrance/frames"
    ADD ROUTE_CONFIG
        WITH OVERLOAD_POLICY "realtime"
    ADD EVENT StartCapture
        WITH QUERY "START"
        WITH SOURCE_TOPIC "video/entrance/control/start"
    ADD EVENT StopCapture
        WITH QUERY "STOP"
        WITH SOURCE_TOPIC "video/entrance/control/stop"

See Connector overload.

Pair with Video Output

TYPE VIDEO_OUTPUT serves those JPEGs as an HTTP MJPEG stream. Set its source topic to this connector’s frame topic.

DEFINE ROUTE OperatorView WITH TYPE VIDEO_OUTPUT
    ADD VIDEO_OUTPUT_CONFIG
        WITH SOURCE_TOPIC "video/entrance/frames"
        WITH OUTPUT_PROTOCOL "HTTP"
        WITH OUTPUT_PATH ":8080/entrance"
    ADD EVENT StartView
        WITH QUERY "START"

Operators open http://<broker-host>:8080/entrance. The same frame topic can feed a Barcode decode event. Audio Input is the microphone equivalent: raw PCM chunks instead of JPEGs, also through FFmpeg.

Best Practices

Keep secrets out of LoT

WITH SOURCE GET ENV "CAMERA_RTSP_URL" or GET SECRET. Do not paste rtsp://user:password@… into the connector.

Match the host

webcam:N on macOS and Linux. video=Exact Name on Windows. A missing video= prefix is opened as a file.

Separate control from frames

Put START and STOP on …/control/… topics. Publishing START on the frame topic mixes commands with JPEG payloads.

Prefer a network camera in Docker Desktop

USB cameras rarely appear inside macOS or Windows Docker Desktop. Use RTSP or HTTP unless the broker runs on Linux with a device mount.

Troubleshooting

FFmpeg is missing

ffmpeg -version on the broker host. Install FFmpeg there, or switch to the slim image.

webcam:0 opens as a file

Use webcam:0 on macOS and Linux. On Windows use video= plus the DirectShow name.

Linux device missing

ls -l /dev/video*. Plug in the camera or pass --device /dev/video0 into the container.

Windows rejects webcam:N

List devices with ffmpeg -list_devices true -f dshow -i dummy and set WITH SOURCE "video=…".

macOS permission or a busy camera

Grant Camera access to the process that launched the broker. Close other apps using the camera. Try webcam:1 for a USB camera.

RTSP or HTTP never starts

The timeout is 10 seconds. From the broker host, confirm the URL is reachable and that RTSP allows TCP. Put the full URL in GET ENV.

Dashboards stall

Lower FRAME_RATE, shrink WIDTH and HEIGHT, or raise QUALITY. Add ADD ROUTE_CONFIG with OVERLOAD_POLICY realtime.

Quick Start

Coreflux MQTT Broker

LoT Language

Coreflux HUB

VS Code - LoT Notebooks

Coreflux Portal

Using AI with Coreflux

Product Updates

Publish camera frames to MQTT

When to use this

Quick Start

Configuration

Capture sources

List devices on the broker host

Events

Docker and FFmpeg

Payload size

Pair with Video Output

Best Practices

Troubleshooting

Next Steps

Audio Input

Barcode Connector

​Publish camera frames to MQTT

​When to use this

​Quick Start

​Configuration

​Capture sources

​List devices on the broker host

​Events

​Docker and FFmpeg

​Payload size

​Pair with Video Output

​Best Practices

​Troubleshooting

​Next Steps

Audio Input

Barcode Connector

Publish camera frames to MQTT

When to use this

Quick Start

Configuration

Capture sources

List devices on the broker host

Events

Docker and FFmpeg

Payload size

Pair with Video Output

Best Practices

Troubleshooting

Next Steps