Ip Camera

Description

Records video in small segments (in case of a cut) and store it locally. They are first stored in a temporary folder. Once the record (of e.g 10 seconds) is done, it is moved to another directory.

Compared to other plugins, the collect function only moves the files from the temporary location, it does not start the recording. It takes some time to establish connection, so we avoid doing this every time. Recording is started at initialization by an ffmpeg process and saved in HLS format.

Parameters

Parameter	Description	Type	Default
input	Input url	str	N/A (Mandatory)
video	Enable video recording	bool	true
audio	Enable audio recording	bool	false
bitrate_video	Video bitrate	str(`[0-9]+[kmKM]`)	"2M"
bitrate_audio	Audio bitrate	str(`[0-9]+[kmKM]`)	"192k"
segment	Records by small segment, managed by ffmpeg	bool	true
segment_time	Duration of a segment	int (>0)	10
ffmpeg_log_level	Ffmpeg log level	str (See doc)	"info"
ffmpeg_banner	Show ffmpeg banner in console	bool	true
save_path	Path used to save files with ffmpeg, UTC date is used	str	"ffmpeg_%Y-%m-%dT%H:%M:%S"

The global save_local_base_path default crashes this Measurement

onConfigure() expands %Y/%M/%D/%H in the directory it creates (dc_util::expand_time(storage_dir_)), but collect() later iterates storage_dir_ unexpanded, as a literal path — and the default global save_local_base_path ($HOME/ros2/data/%Y/%M/%D/%H, see Measurements) contains exactly those placeholders. The first collect() call throws an uncaught std::filesystem::filesystem_error ("cannot open directory: No such file or directory") and takes down the whole measurement_server process, along with every other Measurement it runs. This is a known issue, still unfixed. Set a save_local_base_path with no % placeholders (e.g. /var/lib/dc) to avoid it; save_path itself is unaffected, since only its parent directory is extracted into storage_dir_.

Schema

{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "title": "Ip Camera",
    "description": "Local and remote path where the remote camera video is recorded",
    "properties": {
        "local_path": {
            "description": "Local video path",
            "type": "string"
        },
        "remote_path": {
            "description": "Remote video path",
            "type": "string"
        }
    },
    "type": "object"
}

Configuration

...
ip_camera:
  plugin: "dc_measurements/IpCamera"
  topic_output: "/dc/measurement/ip_camera"
  input: "rtsp://192.168.0.10:554/stream1"
  segment_time: 10
  save_path: "ip_camera/%Y-%m-%dT%H-%M-%S"

Example output

Captured from a real run, input pointed at a real-time MPEG-TS/TCP test stream (save_local_base_path overridden per the warning above):

{
  "data_src": "ip_camera",
  "flattened": false,
  "local_path": "/root/dc_capture_out/ip_camera/ffmpeg_2026-09-06T00:02:30.ts",
  "name": "ip_camera",
  "nested": false,
  "remote_path": "/ip_camera/ffmpeg_2026-09-06T00:02:30.ts",
  "run_id": "169",
  "timestamp": "ffmpeg_2026-09-06T00:02:30"
}

Data Collection for ROS 2