Implements YASS-inspired automatic exposure control for IDS uEye cameras.
The intervalometer filter analyzes video brightness in real-time and
smoothly ramps camera exposure and gain settings during changing light
conditions - ideal for sunset/sunrise time-lapse photography.
Key features:
- Automatic exposure ramping (0.85-1.24ms configurable range)
- Automatic gain control (0-52 configurable range)
- Real-time brightness analysis (GRAY8, GRAY16, RGB, BGR, BGRA)
- YASS-inspired ramping algorithm (exposure priority, then gain)
- Configurable ramp rates (VSlow/Slow/Medium/Fast/VFast)
- Exposure compensation (±4 stops)
- CSV logging of exposure parameters
- Direct GObject property control (no message bus overhead)
Technical implementation:
- GstBaseTransform filter for in-place processing
- Discovers upstream camera element by name
- Controls camera via g_object_set() for synchronous updates
- Frame-by-frame brightness calculation with format support
Files added:
- gst/intervalometer/gstintervalometer.c: Main implementation (734 lines)
- gst/intervalometer/gstintervalometer.h: Header with structure definitions
- gst/intervalometer/CMakeLists.txt: Build configuration
- gst/intervalometer/README.md: Comprehensive documentation
Files modified:
- gst/CMakeLists.txt: Added intervalometer subdirectory
- build.ps1: Added intervalometer to build and deployment pipeline
Usage example:
gst-launch-1.0 idsueyesrc name=cam ! \\
intervalometer enabled=true camera-element=cam \\
exposure-min=0.85 exposure-max=1.24 \\
gain-min=0 gain-max=52 ramp-rate=medium ! \\
autovideosink
Inspired by YASS (Yet Another Sunset Script) for CHDK cameras by
waterwingz, based on work by Fbonomi and soulf2.
- Implements GStreamer element that analyzes pixel columns
- Drops frames when column mean deviates from rolling baseline
- Configurable window size, column index, stride, and threshold
- Includes design documentation and build script
- Tested successfully with IDS uEye camera source
More sensible defaults and allow for overriding. Also make PDB installation
optional on Windows if RelWithDebInfo isn't the build type being used.
CMAKE_INSTALL_PREFIX defaults to GStreamer install location on Windows and
/usr/lib on other platforms.
PLUGIN_INSTALL_DIR defaults to CMAKE_INSTALL_PREFIX/gstreamer-1.0
LIBRARY_INSTALL_DIR defaults to CMAKE_INSTALL_PREFIX/
PDB_INSTALL_DIR defaults to CMAKE_INSTALL_PREFIX/
This is a convenience function to avoid using a capssetter when we want to treat
Bayer as gray. In the future we can add properties to balance each element of the
CFA.
Note there's a bug with the in-place transform, so currently a memcpy is being used.
Some newer version of GStreamer requires the plugin name used in
GST_PLUGIN_DEFINE to match the name of the compiled module, excluding
libgst and the extension.
