When a valid event is detected, a video will be recorded for x seconds. When more valid events are detected, while a video is recording, the video file will further record for x seconds; so no new video file be recorded, but the existing one will be expanded.


The parameters of the Video output device can be found in the config/io.xml file, but you can also use the web to modify the parameters. Below you see a default configuration file.

		<fps type="number">3</fps>
		<recordAfter type="number">5</recordAfter>
		<maxDuration type="number">120</maxDuration>
		<extension type="number">mp4</extension>
		<codec type="number">h264</codec>
		<fileFormat type="text">timestamp_microseconds_instanceName_regionCoordinates_numberOfChanges_token</fileFormat>
		<directory type="text">/etc/opt/kerberosio/capture/</directory>
		<hardwareDirectory type="text">/etc/opt/kerberosio/h264/</hardwareDirectory>
		<enableHardwareEncoding type="bool">true</enableHardwareEncoding>
		<markWithTimestamp type="bool">false</markWithTimestamp>
		<timestampColor type="text">white</timestampColor>
		<privacy type="bool">false</privacy>


The frames per second of the video being recorded. Please note that this number is limited and depends heavily on your hardware setup. You'll be receiving following warning in the systems logs, if can't write the desired FPS. When using an USB or IP camera, we recommend recording at 5-8FPS for a Rasberry Pi 2/3.

[trivial] IoVideo: framerate is too fast, can't record video at this speed (8/FPS)

Note that when you're a using a Raspberry Pi camera, there is no limitation on the FPS due to the hardware encoding. For example you can record at 1080P 30FPS with a Raspberry Pi Zero W.

Record after

The number of seconds recorded after the last valid event was detected. This means that when a video is already recording, and a valid event was detected, the video will be expanded with x more seconds.


The extension or container of the video file. We highly recommend to use the MP4 container if you want cross-browser support. Leave this setting by default, if you don't know what you're doing.


The codec that is used to encode the video file.

File format

The format that will be used for the name of the image. One or more variables can be defined and will be replaced by the machinery. Note that when you're using a variables name in the file format, that this name should be defined in the JSON object.


The directory where the videos will be saved. By default videos are saved to the /etc/opt/kerberosio/capture directory.

Hardware directory

When using onboard hardware encoding (e.g. with Raspberry Pi camera), h264 video files are generated and stored in this directory. Afterwards these h264 files will be containerized to mp4 files, and stored in the Directory path.

Enable Hardware encoding

A boolean which can enable or disable hardware encoding. Please note that this option is enabled by default, but does not mean that it will work if you choose to use an USB camera.

Mark with timestamp

When this settings is set to true, the video is marked with a timestamp (similar to the Disk device).

Disk timestamp

Timestamp color

A color can be defined for timestamp: white, black, red, green and blue.


The privacy mode can be activated to remove some parts from the video. This especially helpful if you want to filter out public areas.

Video privacy

After updating the configuration, you'll see that the pixels outside your region of interest (ROI) are made black; the image below illustrates this.

Video privacy