OM1 Telemetry Recorder

A Go application that synchronously records multi-modal sensor data:

• Video from RTSP streams (via ffmpeg) — multiple cameras
• Audio from RTSP streams (via ffmpeg)
• Lidar point clouds from Zenoh topics
• Depth frames from Zenoh topics (RVL-compressed, lossless)
• Odometry messages from Zenoh topics

All streams are timestamped and organized into session directories for easy alignment and analysis.

Prerequisites

• Go 1.25 or later
• ffmpeg installed and available in PATH
• zenoh-c library (automatically downloaded via make download-zenohc)

Configuration

Configure via environment variables:

• ENABLE_COLLECTION - Enable/disable data collection (default: true; set to false, 0, or no to disable)
• TOP_CAMERA_RTSP_URL - Top camera stream URL (default: rtsp://localhost:8554/top_camera_raw)
• FRONT_CAMERA_RTSP_URL - Front camera stream URL (default: rtsp://localhost:8554/front_camera)
• DOWN_CAMERA_RTSP_URL - Down camera stream URL (default: rtsp://localhost:8554/down_camera)
• AUDIO_RTSP_URL - Audio stream URL (default: rtsp://localhost:8554/audio)
• LIDAR_ZENOH_ENDPOINT - Zenoh endpoint for lidar (default: tcp/127.0.0.1:7447)
• LIDAR_ZENOH_TOPIC - Zenoh topic for lidar data (default: scan)
• DEPTH_ZENOH_ENDPOINT - Zenoh endpoint for depth (default: tcp/127.0.0.1:7447)
• DEPTH_ZENOH_TOPIC - Zenoh topic for depth frames (default: camera/realsense2_camera_node/depth/image_rect_raw)
• ODOM_ZENOH_ENDPOINT - Zenoh endpoint for odometry (default: tcp/127.0.0.1:7447)
• ODOM_ZENOH_TOPIC - Zenoh topic for odometry data (default: odom)
• RECORDINGS_DIR - Base directory for recordings (default: recordings)

Building

Download the zenoh-c library and build the binary:

make download-zenohc
make build

The binary will be created at bin/om1-telemetry.

Running

./bin/om1-telemetry

Or with custom settings:

ENABLE_COLLECTION=true \
TOP_CAMERA_RTSP_URL="rtsp://camera.local/top_camera_raw" \
FRONT_CAMERA_RTSP_URL="rtsp://camera.local/front_camera" \
DOWN_CAMERA_RTSP_URL="rtsp://camera.local/down_camera" \
AUDIO_RTSP_URL="rtsp://camera.local/audio" \
LIDAR_ZENOH_ENDPOINT="tcp/192.168.1.10:7447" \
LIDAR_ZENOH_TOPIC="scan" \
DEPTH_ZENOH_ENDPOINT="tcp/192.168.1.10:7447" \
DEPTH_ZENOH_TOPIC="camera/realsense2_camera_node/depth/image_rect_raw" \
ODOM_ZENOH_ENDPOINT="tcp/192.168.1.10:7447" \
ODOM_ZENOH_TOPIC="odom" \
RECORDINGS_DIR="/path/to/recordings" \
./bin/om1-telemetry

Session Output

Each recording session creates a timestamped directory structure:

recordings/
└── 2026-05-15/
    └── 2026-05-15_14-30-00/
        ├── meta.json                  # Session metadata
        ├── top_camera.mp4             # Top camera recording
        ├── front_camera.mp4           # Front camera recording
        ├── down_camera.mp4            # Down camera recording
        ├── audio.ogg                  # Audio recording
        ├── lidar_scans.bin            # Raw lidar point cloud data
        ├── lidar_timestamps.csv       # Timestamps: unix_ns,seq,byte_offset
        ├── depth_frames.bin           # RVL-compressed depth frames (lossless)
        ├── depth_timestamps.csv       # unix_ns,seq,byte_offset,byte_length,method,width,height,encoding
        ├── odom_frames.bin            # Raw odometry messages
        └── odom_timestamps.csv        # Timestamps: unix_ns,seq,byte_offset

Depth frames (RVL)

Each row in depth_timestamps.csv slices one frame out of depth_frames.bin using byte_offset and byte_length. Depth is compressed with RVL (Wilson, Fast Lossless Depth Image Compression, ISS 2017) — a lossless codec designed for 16-bit depth maps, so depth values are preserved exactly while typically using far less space than the raw frames.

The extra columns describe each frame so it can be reconstructed offline:

• method — rvl for RVL-compressed frames, or raw for the fallback (see below).
• width, height — frame dimensions; the decoded frame has width*height 16-bit pixels.
• encoding — the source ROS image encoding (e.g. 16UC1).

To decode a frame: read byte_length bytes at byte_offset, then RVL-decode into width*height little-endian uint16 pixels.

Fallback: if a payload can't be parsed as a 16-bit depth image, it is stored verbatim with method=raw (the original serialized sensor_msgs/Image), so no data is ever lost — those rows are decoded by parsing the ROS message directly.

Testing

Run the test suite:

make test

Run tests for a specific package:

make test

Development

• Linting: make lint (requires golangci-lint)
• Tidy dependencies: make tidy