Source Tweak Parameters for CamGear API⚓
These tweak parameters can be used to transform input Camera-Source properties (such as its brightness, saturation, resolution, iso, gain etc.) seamlessly. All parameters supported by CamGear API are disscussed in this document.
Exclusive CamGear Attributes⚓
CamGear's Exclusive Attributes
In addition to Source Tweak Parameters, CamGear also provides some exclusive attributes for its
options dictionary parameters.
These attributes are as follows:
STREAM_RESOLUTION(string): This attribute can be used in CamGear's Stream Mode (
stream_mode=True) for specifying supported stream resolution. Its possible values can be:
best, and its default value is
best. Its usage is as follows:
In case specificed
STREAM_RESOLUTIONvalue is unavailable within Source Stream, it defaults to
Its complete usage example is given here ➶
STREAM_PARAMS(dict): This dictionary attribute can be used in CamGear's Stream Mode (
stream_mode=True) for specifying parameters for its internal
yt_dlpbackend class. Its usage is as follows:
- All yt_dlp parameter can be found here ➶
THREADED_QUEUE_MODE(boolean): This attribute can be used to override Threaded-Queue-Mode mode to manually disable it:
Disabling Threaded-Queue-Mode can be dangerous! Read more here ➶
THREAD_TIMEOUT(int/float): This attribute can be used to override the timeout value(positive number), that blocks the video-thread for at most timeout seconds if no video-frame was available within that time, and otherwise raises the Empty exception to prevent any never-ending deadlocks. Its default value is
None, meaning no timeout at all. Its usage is as follows:
New in v0.2.1
THREAD_TIMEOUTattribute added in
Supported Source Tweak Parameters⚓
All Source Tweak Parameters supported by CamGear API are as follows:
Remember, Not all parameters are supported by all cameras devices, which is one of the most troublesome thing with OpenCV library. Each camera type, from android cameras, to USB cameras , to professional ones, offers a different interface to modify its parameters. Therefore, there are many branches in OpenCV code to support as many of them, but of course, not all possible devices are covered, and thereby works. Furthermore, OpenCV does not return any helpful error messages regarding this problem, so it’s pretty much based on trial and error.
You can easily check parameter values supported by your webcam, by hooking it to a Linux machine, and using the command
v4l2-ctl -d 0 --list-formats-ext (where 0 is an index of the given camera) to list the supported video parameters and their values. If that doesn't works, refer to its datasheet (if available).
|Current position of the video file in milliseconds.
|0-based index of the frame to be decoded/captured next.
|Relative position of the video file: 0=start of the film, 1=end of the film.
|Width of the frames in the video stream.
|Height of the frames in the video stream.
|4-character code of codec. see VideoWriter::fourcc.
|Number of frames in the video file.
|Format of the Mat objects returned by VideoCapture::retrieve().
|Backend-specific value indicating the current capture mode.
|Brightness of the image (only for those cameras that support).
|Contrast of the image (only for cameras).
|Saturation of the image (only for cameras).
|Hue of the image (only for cameras).
|Gain of the image (only for those cameras that support).
|Exposure (only for those cameras that support).
|Boolean flags indicating whether images should be converted to RGB.
|Rectification flag for stereo cameras (note: only supported by DC1394 v 2.x backend currently).
|DC1394: exposure control done by camera, user can adjust reference level using this feature.
|Pop up video/camera filter dialog (note: only supported by DSHOW backend currently. The property value is ignored)
|Sample aspect ratio: num/den (num)
|Sample aspect ratio: num/den (den)
|Current backend (enum VideoCapture APIs). Read-only property.
|Video input or Channel Number (only for those cameras that support)
|enable/ disable auto white-balance
|white-balance color temperature