Class VideoCapture
- Namespace
- OpenCvSharp
- Assembly
- OpenCvSharp.dll
Video capturing class
public class VideoCapture : CvObject, IDisposable- Inheritance
-
VideoCapture
- Implements
- Inherited Members
Constructors
- VideoCapture()
Initializes empty capture. To use this, you should call Open.
- VideoCapture(IStreamReader, VideoCaptureAPIs, VideoCapturePara)
Opens a video using a custom data stream.
- VideoCapture(IStreamReader, VideoCaptureAPIs, int[])
Opens a video using a custom data stream.
- VideoCapture(Stream, VideoCaptureAPIs, VideoCapturePara)
Opens a video using an in-memory or otherwise custom Stream (e.g. a MemoryStream or network stream). The caller remains responsible for disposing the stream; VideoCapture does not take ownership of it.
- VideoCapture(Stream, VideoCaptureAPIs, int[])
Opens a video using an in-memory or otherwise custom Stream (e.g. a MemoryStream or network stream). The caller remains responsible for disposing the stream; VideoCapture does not take ownership of it.
- VideoCapture(int, VideoCaptureAPIs)
Opens a camera for video capturing
- VideoCapture(int, VideoCaptureAPIs, VideoCapturePara)
Opens a camera for video capturing with API Preference and parameters
- VideoCapture(int, VideoCaptureAPIs, int[])
Opens a camera for video capturing with API Preference and parameters
- VideoCapture(nint)
Initializes from native pointer
- VideoCapture(string, VideoCaptureAPIs)
Opens a video file or a capturing device or an IP video stream for video capturing with API Preference
- VideoCapture(string, VideoCaptureAPIs, VideoCapturePara)
Opens a video file or a capturing device or an IP video stream for video capturing with API Preference
- VideoCapture(string, VideoCaptureAPIs, int[])
Opens a video file or a capturing device or an IP video stream for video capturing with API Preference
Properties
- AutoExposure
exposure control done by camera, user can adjust refernce level using this feature [CV_CAP_PROP_AUTO_EXPOSURE]
- Brightness
Gets or sets brightness of image (only for cameras)
- CaptureType
Gets the capture type (File or Camera)
- Contrast
Gets or sets contrast of image (only for cameras)
- ConvertRgb
Boolean flags indicating whether images should be converted to RGB
- Exposure
Exposure (only for cameras)
- Format
The format of the Mat objects returned by retrieve()
- FourCC
Gets or sets 4-character code of codec
- Fps
Gets or sets frame rate
- FrameCount
Gets number of frames in video file
- FrameHeight
Gets or sets height of frames in the video stream
- FrameWidth
Gets or sets width of frames in the video stream
- GStreamerQueueLength
default is 1 [CV_CAP_GSTREAMER_QUEUE_LENGTH]
- Gain
Gain of the image (only for cameras)
- Hue
Gets or sets hue of image (only for cameras)
- Mode
A backend-specific value indicating the current capture mode
- OpenNI_Baseline
in mm [CV_CAP_PROP_OPENNI_BASELINE]
- OpenNI_DepthGeneratorBaseline
[CV_CAP_OPENNI_DEPTH_GENERATOR_BASELINE]
- OpenNI_DepthGeneratorFocalLength
[CV_CAP_OPENNI_DEPTH_GENERATOR_FOCAL_LENGTH]
- OpenNI_DepthGeneratorRegistrationON
[CV_CAP_OPENNI_DEPTH_GENERATOR_REGISTRATION_ON]
- OpenNI_FocalLength
in pixels [CV_CAP_PROP_OPENNI_FOCAL_LENGTH]
- OpenNI_FrameMaxDepth
in mm [CV_CAP_PROP_OPENNI_FRAME_MAX_DEPTH]
- OpenNI_ImageGeneratorOutputMode
[CV_CAP_OPENNI_IMAGE_GENERATOR_OUTPUT_MODE]
- OpenNI_OutputMode
[CV_CAP_PROP_OPENNI_OUTPUT_MODE]
- OpenNI_Registration
flag that synchronizes the remapping depth map to image map by changing depth generator's view point (if the flag is "on") or sets this view point to its normal one (if the flag is "off"). [CV_CAP_PROP_OPENNI_REGISTRATION]
- PosAviRatio
Gets or sets relative position of video file
- PosFrames
Gets or sets 0-based index of the frame to be decoded/captured next
- PosMsec
Gets or sets film current position in milliseconds or video capture timestamp
- PvAPIMulticastIP
ip for anable multicast master mode. 0 for disable multicast [CV_CAP_PROP_PVAPI_MULTICASTIP]
- Rectification
TOWRITE (note: only supported by DC1394 v 2.x backend currently)
- Saturation
Gets or sets saturation of image (only for cameras)
- Temperature
[CV_CAP_PROP_TEMPERATURE]
- XI_AEAG
Automatic exposure/gain [CV_CAP_PROP_XI_AEAG]
- XI_AEAGLevel
default is 1 [CV_CAP_PROP_XI_AEAG_LEVEL]
- XI_AEMaxLimit
Maximum limit of exposure in AEAG procedure [CV_CAP_PROP_XI_AE_MAX_LIMIT]
- XI_AGMaxLimit
Maximum limit of gain in AEAG procedure [CV_CAP_PROP_XI_AG_MAX_LIMIT]
- XI_AutoWB
Automatic white balance [CV_CAP_PROP_XI_AUTO_WB]
- XI_DataFormat
Output data format. [CV_CAP_PROP_XI_DATA_FORMAT]
- XI_Downsampling
Change image resolution by binning or skipping.
[CV_CAP_PROP_XI_DOWNSAMPLING]
- XI_ExpPriority
Exposure priority (0.5 - exposure 50%, gain 50%). [CV_CAP_PROP_XI_EXP_PRIORITY]
- XI_GpiLevel
Get general purpose level [CV_CAP_PROP_XI_GPI_LEVEL]
- XI_GpiMode
Set general purpose input mode [CV_CAP_PROP_XI_GPI_MODE]
- XI_GpiSelector
Selects general purpose input [CV_CAP_PROP_XI_GPI_SELECTOR]
- XI_GpoMode
Set general purpose output mode [CV_CAP_PROP_XI_GPO_MODE]
- XI_GpoSelector
Selects general purpose output [CV_CAP_PROP_XI_GPO_SELECTOR]
- XI_LedMode
Define camera signalling LED functionality [CV_CAP_PROP_XI_LED_MODE]
- XI_LedSelector
Selects camera signalling LED [CV_CAP_PROP_XI_LED_SELECTOR]
- XI_ManualWB
Calculates White Balance(must be called during acquisition) [CV_CAP_PROP_XI_MANUAL_WB]
- XI_OffsetX
Horizontal offset from the origin to the area of interest (in pixels). [CV_CAP_PROP_XI_OFFSET_X]
- XI_OffsetY
Vertical offset from the origin to the area of interest (in pixels). [CV_CAP_PROP_XI_OFFSET_Y]
- XI_Timeout
default is 1 [CV_CAP_PROP_XI_TIMEOUT]
- XI_TrgSoftware
Generates an internal trigger. PRM_TRG_SOURCE must be set to TRG_SOFTWARE. [CV_CAP_PROP_XI_TRG_SOFTWARE]
- XI_TrgSource
Defines source of trigger. [CV_CAP_PROP_XI_TRG_SOURCE]
Methods
- FromCamera(int, VideoCaptureAPIs)
Opens a camera for video capturing
- FromFile(string, VideoCaptureAPIs)
Opens a video file or a capturing device or an IP video stream for video capturing with API Preference
- Get(VideoCaptureProperties)
Returns the specified VideoCapture property
- Get(int)
Returns the specified VideoCapture property
- GetBackendName()
Returns used backend API name. Note that stream should be opened.
- GetExceptionMode()
query if exception mode is active
- Grab()
Grabs the next frame from video file or capturing device.
The method/function grabs the next frame from video file or camera and returns true (non-zero) in the case of success.
The primary use of the function is in multi-camera environments, especially when the cameras do not have hardware synchronization. That is, you call VideoCapture::grab() for each camera and after that call the slower method VideoCapture::retrieve() to decode and get frame from each camera. This way the overhead on demosaicing or motion jpeg decompression etc. is eliminated and the retrieved frames from different cameras will be closer in time.
Also, when a connected camera is multi-head (for example, a stereo camera or a Kinect device), the correct way of retrieving data from it is to call VideoCapture::grab() first and then call VideoCapture::retrieve() one or more times with different values of the channel parameter.
- IsOpened()
Returns true if video capturing has been initialized already.
- Open(IStreamReader, VideoCaptureAPIs, VideoCapturePara)
Opens a video using a custom data stream.
- Open(IStreamReader, VideoCaptureAPIs, int[])
Opens a video using a custom data stream.
- Open(Stream, VideoCaptureAPIs, VideoCapturePara)
Opens a video using an in-memory or otherwise custom Stream (e.g. a MemoryStream or network stream). The caller remains responsible for disposing the stream; VideoCapture does not take ownership of it.
- Open(Stream, VideoCaptureAPIs, int[])
Opens a video using an in-memory or otherwise custom Stream (e.g. a MemoryStream or network stream). The caller remains responsible for disposing the stream; VideoCapture does not take ownership of it.
- Open(int, VideoCaptureAPIs)
Opens a camera for video capturing
- Open(string, VideoCaptureAPIs)
Opens a video file or a capturing device or an IP video stream for video capturing.
- Open(string, VideoCaptureAPIs, VideoCapturePara)
Opens a video file or a capturing device or an IP video stream for video capturing with API Preference and parameters
- Open(string, VideoCaptureAPIs, int[])
Opens a video file or a capturing device or an IP video stream for video capturing with API Preference and parameters
- Read(Mat)
Grabs, decodes and returns the next video frame.
The method/function combines VideoCapture::grab() and VideoCapture::retrieve() in one call. This is the most convenient method for reading video files or capturing data from decode and returns the just grabbed frame. If no frames has been grabbed (camera has been disconnected, or there are no more frames in video file), the method returns false and the function returns empty image (with %cv::Mat, test it with Mat::empty()).
- Read(OutputArray)
Grabs, decodes and returns the next video frame.
The method/function combines VideoCapture::grab() and VideoCapture::retrieve() in one call. This is the most convenient method for reading video files or capturing data from decode and returns the just grabbed frame. If no frames has been grabbed (camera has been disconnected, or there are no more frames in video file), the method returns false and the function returns empty image (with %cv::Mat, test it with Mat::empty()).
- Release()
Closes video file or capturing device.
- Retrieve(Mat, CameraChannels)
Decodes and returns the grabbed video frame.
The method decodes and returns the just grabbed frame. If no frames has been grabbed (camera has been disconnected, or there are no more frames in video file), the method returns false and the function returns an empty image (with %cv::Mat, test it with Mat::empty()).
- Retrieve(Mat, int)
Decodes and returns the grabbed video frame.
The method decodes and returns the just grabbed frame. If no frames has been grabbed (camera has been disconnected, or there are no more frames in video file), the method returns false and the function returns an empty image (with %cv::Mat, test it with Mat::empty()).
- Retrieve(OutputArray, CameraChannels)
Decodes and returns the grabbed video frame.
The method decodes and returns the just grabbed frame. If no frames has been grabbed (camera has been disconnected, or there are no more frames in video file), the method returns false and the function returns an empty image (with %cv::Mat, test it with Mat::empty()).
- Retrieve(OutputArray, int)
Decodes and returns the grabbed video frame.
The method decodes and returns the just grabbed frame. If no frames has been grabbed (camera has been disconnected, or there are no more frames in video file), the method returns false and the function returns an empty image (with %cv::Mat, test it with Mat::empty()).
- RetrieveMat()
Decodes and returns the grabbed video frame.
The method decodes and returns the just grabbed frame. If no frames has been grabbed (camera has been disconnected, or there are no more frames in video file), the method returns false and the function returns an empty image (with %cv::Mat, test it with Mat::empty()).
- Set(VideoCaptureProperties, double)
Sets a property in the VideoCapture.
- Set(int, double)
Sets a property in the VideoCapture.
- SetExceptionMode(bool)
Switches exceptions mode. methods raise exceptions if not successful instead of returning an error code
- WaitAny(IEnumerable<VideoCapture>, out int[], long)
Wait for ready frames from VideoCapture.
The primary use of the function is in multi-camera environments. The method fills the ready state vector, grabs video frame, if camera is ready.
After this call use VideoCapture::retrieve() to decode and fetch frame data.