roboflex.webcam_gst

Support for USB and built-in webcams using GStreamer. This module is a drop-in alternative to roboflex_webcamuvc, but it avoids the libuvc dependency and instead drives cameras through the GStreamer stack. The message schema and Python/C++ APIs are kept as close as possible to the original UVC implementation.

System dependencies

GStreamer and its development headers are required at build time:

# Ubuntu / Debian
sudo apt install libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev gstreamer1.0-plugins-good

# macOS (Homebrew)
brew install gstreamer gst-plugins-base gst-plugins-good

Install

The project can be built like other roboflex modules:

pip install roboflex.webcam_gst

or from source with CMake.

Python usage

import roboflex.webcam_gst as rcw

print(rcw.get_device_list_string())

sensor = rcw.WebcamSensor(
    width=640,
    height=480,
    fps=30,
    device_index=-1,  # use default camera
    format="",  # empty string lets GStreamer pick
    emit_rgb=True,
)

sensor.start()
try:
    # consume messages...
    pass
finally:
    sensor.stop()

The emitted messages (WebcamDataRGB / WebcamDataRaw) match the original module so downstream nodes can continue to operate without changes.

Device descriptors

get_device_list() returns DeviceDescriptor objects with the following fields:

• display_name: Human-readable label reported by GStreamer.
• gst_factory_name: The underlying factory name used by GStreamer.
• device_class: The class of device (e.g. Video/Source).
• device_path: OS-specific identifier when available.
• caps_strings: A list of capability structures advertised by the device.

Notes

• RGB output is enabled by default. Set emit_rgb=False to receive raw frames; use the format parameter to request a specific pixel format string (e.g. "NV12" or "YUY2"), subject to what the device supports.
• The helper WebcamRawToRGBConverter currently expects RGB input; raise an exception otherwise. Most workflows should request RGB directly from the sensor.
• Because we rely on GStreamer, the available devices and pixel formats depend on the plugins installed on your system.