Module opencv::videoio [−][src]
Expand description
Video I/O
Read and write video or images sequence with OpenCV
See also:
- @ref videoio_overview
- Tutorials: @ref tutorial_table_of_content_app
Flags for video I/O
Additional flags for video I/O API backends
Hardware-accelerated video decoding and encoding
C API for video I/O
iOS glue for video I/O
WinRT glue for video I/O
Query I/O API backends registry
Modules
Structs
Class for video capturing from video files, image sequences or cameras.
Video writer class.
Enums
Video Acceleration type
cv::VideoCapture API backends identifier.
cv::VideoCapture generic properties identifier.
cv::VideoWriter generic properties identifier.
Constants
Android - not used
Auto detect == 0
Aravis SDK
AVFoundation framework for iOS (OS X Lion will have the same API)
Same value as CAP_FIREWIRE
Same value as CAP_FIREWIRE
DirectShow (via videoInput)
Open and record video file or stream using the FFMPEG library
Same value as CAP_FIREWIRE
IEEE 1394 drivers
Smartek Giganetix GigEVisionSDK
gPhoto2 connection
GStreamer
Same value as CAP_FIREWIRE
OpenCV Image Sequence (e.g. img_%02d.jpg)
RealSense (former Intel Perceptual Computing SDK)
Each pixel is a 16-bit integer. The value indicates the distance from an object to the camera’s XY plane or the Cartesian depth.
Each pixel is a 16-bit integer. The value indicates the intensity of the reflected laser beam.
Each pixel contains two 32-bit floating point values in the range of 0-1, representing the mapping of depth coordinates to the color coordinates.
Intel MediaSDK
Microsoft Media Foundation (via videoInput)
Built-in OpenCV MotionJPEG codec
OpenNI (for Kinect)
OpenNI2 (for Kinect)
OpenNI2 (for Orbbec Astra)
OpenNI2 (for Asus Xtion and Occipital Structure sensors)
OpenNI (for Asus Xtion)
Data given from RGB image generator
Depth values in mm (CV_16UC1)
Disparity in pixels (CV_8UC1)
Disparity in pixels (CV_32FC1)
Data given from RGB image generator
Data given from IR image generator
XYZ in meters (CV_32FC3)
CV_8UC1
Aperture. Can be readonly, depends on camera program.
Automatically trigger frame capture if camera is configured with software trigger
DC1394: exposure control done by camera, user can adjust reference level using this feature.
enable/ disable auto white-balance
Current backend (enum VideoCaptureAPIs). Read-only property
(read-only) Video bitrate in kbits/s
Brightness of the image (only for those cameras that support).
Video input or Channel Number (only for those cameras that support)
(read-only) codec’s pixel format. 4-character code - see VideoWriter::fourcc . Subset of AV_PIX_FMT_* or -1 if unknown
Contrast of the image (only for cameras).
Boolean flags indicating whether images should be converted to RGB.
GStreamer note: The flag is ignored in case if custom pipeline is used. It’s user responsibility to interpret pipeline output.
set automatically when a value of the feature is set by the user.
turn the feature off (not controlled manually nor automatically).
Exposure (only for those cameras that support).
Camera exposure program.
Format of the %Mat objects (see Mat::type()) returned by VideoCapture::retrieve(). Set value -1 to fetch undecoded RAW video streams (as Mat 8UC1).
4-character code of codec. see VideoWriter::fourcc .
Frame rate.
Number of frames in the video file.
Height of the frames in the video stream.
Width of the frames in the video stream.
Gain of the image (only for those cameras that support).
Collect messages with details.
Readonly, returns (const char *).
Capture only preview from liveview mode.
Trigger, only by set. Reload camera settings.
Reload all settings on set.
Readonly, returns (const char *).
Default is 1
Hue of the image (only for cameras).
(open-only) Hardware acceleration type (see #VideoAccelerationType). Setting supported only via params parameter in cv::VideoCapture constructor / .open() method. Default value is backend-specific.
(open-only) If non-zero, create new OpenCL context and bind it to current thread. The OpenCL context created with Video Acceleration context attached it (if not attached yet) for optimized GPU data copy between HW accelerated decoder and cv::UMat.
(open-only) Hardware device index (select GPU if multiple available). Device enumeration is acceleration type specific.
Backend-specific value indicating the current capture mode.
In pixels
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”).
(open-only) timeout in milliseconds for opening a video capture (applicable for FFmpeg back-end only)
if true - rotates output frames of CvCapture considering video file’s metadata (applicable for FFmpeg back-end only) (https://github.com/opencv/opencv/issues/15499)
(read-only) Frame rotation defined by stream meta (applicable for FFmpeg back-end only)
Relative position of the video file: 0=start of the film, 1=end of the film.
0-based index of the frame to be decoded/captured next.
Current position of the video file in milliseconds.
Horizontal binning factor.
Vertical binning factor.
Horizontal sub-sampling of the image.
Vertical sub-sampling of the image.
FrameStartTriggerMode: Determines how a frame is initiated.
IP for enable multicast master mode. 0 for disable multicast.
Pixel format.
(open-only) timeout in milliseconds for reading from a video capture (applicable for FFmpeg back-end only)
Rectification flag for stereo cameras (note: only supported by DC1394 v 2.x backend currently).
Sample aspect ratio: num/den (den)
Sample aspect ratio: num/den (num)
Saturation of the image (only for cameras).
Pop up video/camera filter dialog (note: only supported by DSHOW backend currently. The property value is ignored)
Exposure speed. Can be readonly, depends on camera program.
Enter liveview mode.
white-balance color temperature
Currently unsupported.
Acquisition buffer size in buffer_size_unit. Default bytes.
Acquisition buffer size unit in bytes. Default 1. E.g. Value 1024 means that buffer_size is in KiBytes.
Sets number of frames acquired by burst. This burst is used only if trigger is set to FrameBurstStart.
Type of sensor frames timing.
Number of buffers to commit to low level.
Acquisition transport buffer size in bytes.
Automatic exposure/gain.
Average intensity of output signal AEAG should achieve(in %).
Automatic exposure/gain ROI Height.
Automatic exposure/gain ROI offset X.
Automatic exposure/gain ROI offset Y.
Automatic exposure/gain ROI Width.
Maximum limit of exposure in AEAG procedure.
Maximum limit of gain in AEAG procedure.
Enable applying of CMS profiles to xiGetImage (see XI_PRM_INPUT_CMS_PROFILE, XI_PRM_OUTPUT_CMS_PROFILE).
Automatic bandwidth calculation.
Automatic white balance.
Calculate and returns available interface bandwidth(int Megabits).
Horizontal Binning - number of horizontal photo-sensitive cells to combine together.
Binning pattern type.
Binning engine selector.
Vertical Binning - number of vertical photo-sensitive cells to combine together.
Correction of bad pixels.
Queue of field/frame buffers.
Data move policy.
Color Correction Matrix element [0][0].
Color Correction Matrix element [0][1].
Color Correction Matrix element [0][2].
Color Correction Matrix element [0][3].
Color Correction Matrix element [1][0].
Color Correction Matrix element [1][1].
Color Correction Matrix element [1][2].
Color Correction Matrix element [1][3].
Color Correction Matrix element [2][0].
Color Correction Matrix element [2][1].
Color Correction Matrix element [2][2].
Color Correction Matrix element [2][3].
Color Correction Matrix element [3][0].
Color Correction Matrix element [3][1].
Color Correction Matrix element [3][2].
Color Correction Matrix element [3][3].
Camera sensor temperature.
Mode of color management system.
Returns color filter array type of RAW data.
Correction of column FPN.
Start camera cooling.
Select counter.
Counter status.
Output data format.
Enable/Disable debounce to selected GPI.
Debounce polarity (pol = 1 t0 - falling edge, t1 - rising edge).
Debounce time (x * 10us).
Debounce time (x * 10us).
Set debug level.
Horizontal Decimation - horizontal sub-sampling of the image - reduces the horizontal resolution of the image by the specified vertical decimation factor.
Decimation pattern type.
Decimation engine selector.
Vertical Decimation - vertical sub-sampling of the image - reduces the vertical resolution of the image by the specified vertical decimation factor.
Set default Color Correction Matrix.
Returns device model id.
Resets the camera to default state.
Returns device serial number.
Change image resolution by binning or skipping.
Change image downsampling type.
Exposure time in microseconds.
Sets the number of times of exposure in one frame.
Exposure priority (0.5 - exposure 50%, gain 50%).
Setting of key enables file operations on some cameras.
File number.
Size of file.
Define framerate in Hz.
Size of free camera FFS.
Gain in dB.
Gain selector for parameter Gain allows to select different type of gains.
Chromaticity gamma.
Luminosity gamma.
Get general purpose level.
Set general purpose input mode.
Selects general purpose input.
Set general purpose output mode.
Selects general purpose output.
Enable High Dynamic Range feature.
The number of kneepoints in the PWLR.
Position of first kneepoint(in % of XI_PRM_EXPOSURE).
Position of second kneepoint (in % of XI_PRM_EXPOSURE).
Height of the Image provided by the device (in pixels).
Camera housing back side temperature.
Camera housing temperature.
Returns hardware revision number.
Last image black level counts. Can be used for Offline processing to recall it.
bitdepth of data returned by function xiGetImage.
Output data format.
The alpha channel of RGB32 output image format.
Returns 1 for color cameras.
Buffer size in bytes sufficient for output image returned by xiGetImage.
Returns 1 for cameras that support cooling.
Returns 1 if camera connected and works properly.
Value of first kneepoint (% of sensor saturation).
Value of second kneepoint (% of sensor saturation).
Define camera signalling LED functionality.
Selects camera signalling LED.
Current lens aperture value in stops. Examples: 2.8, 4, 5.6, 8, 11.
Allows access to lens feature value currently selected by XI_PRM_LENS_FEATURE_SELECTOR.
Selects the current feature which is accessible by XI_PRM_LENS_FEATURE.
Lens focal distance in mm.
Lens focus distance in cm.
Moves lens focus motor by steps set in XI_PRM_LENS_FOCUS_MOVEMENT_VALUE.
Lens current focus movement value to be used by XI_PRM_LENS_FOCUS_MOVE in motor steps.
Status of lens control interface. This shall be set to XI_ON before any Lens operations.
Set/get bandwidth(datarate)(in Megabits).
Activates LUT.
Control the index (offset) of the coefficient to access in the LUT.
Value at entry LUTIndex of the LUT.
Calculates White Balance(must be called during acquisition).
Horizontal offset from the origin to the area of interest (in pixels).
Vertical offset from the origin to the area of interest (in pixels).
Device output data bit depth.
Device output data packing (or grouping) enabled. Packing could be enabled if output_data_bit_depth > 8 and packing capability is available.
Data packing type. Some cameras supports only specific packing type.
GetImage returns most recent frame.
Activates/deactivates Region selected by Region Selector.
Selects Region in Multiple ROI which parameters are set by width, height, … ,region mode.
Correction of row FPN.
Camera sensor board temperature.
Sensor clock frequency in Hz.
Sensor clock frequency index. Sensor with selected frequencies have possibility to set the frequency only by this index.
Sensor output data bit depth.
Selects the current feature which is accessible by XI_PRM_SENSOR_FEATURE_VALUE.
Allows access to sensor feature value currently selected by XI_PRM_SENSOR_FEATURE_SELECTOR.
Current sensor mode. Allows to select sensor mode by one integer. Setting of this parameter affects: image dimensions and downsampling.
Number of output channels from sensor used for data transfer.
Number of taps.
Sharpness Strength.
Change sensor shutter type(CMOS sensor).
Set sensor target temperature for cooling.
Selects which test pattern type is generated by the selected generator.
Selects which test pattern generator is controlled by the TestPattern feature.
Image capture timeout in milliseconds.
Current format of pixels on transport layer.
Specifies the delay in microseconds (us) to apply after the trigger reception before activating it.
Selects the type of trigger.
Generates an internal trigger. PRM_TRG_SOURCE must be set to TRG_SOFTWARE.
Defines source of trigger.
Defines how time stamp reset engine will be armed.
Defines which source will be used for timestamp reset. Writing this parameter will trigger settings of engine (arming).
Size of used camera FFS.
White balance blue coefficient.
White balance green coefficient.
White balance red coefficient.
Width of the Image provided by the device (in pixels).
PvAPI, Prosilica GigE SDK
2 out of 4 decimation
2 out of 8 decimation
2 out of 16 decimation
FixedRate
Freerun
Software
SyncIn1
SyncIn2
QuickTime (obsolete, removed)
Synonym for CAP_INTELPERC
uEye Camera API
Unicap drivers (obsolete, removed)
V4L/V4L2 capturing support
Same as CAP_V4L
Video For Windows (obsolete, removed)
Microsoft Windows Runtime using Media Foundation
XIMEA Camera API
XINE engine (Linux)
Defaults to CV_8U.
(Read-only): Size of just encoded video frame. Note that the encoding order may be different from representation order.
(open-only) Hardware acceleration type (see #VideoAccelerationType). Setting supported only via params parameter in VideoWriter constructor / .open() method. Default value is backend-specific.
(open-only) If non-zero, create new OpenCL context and bind it to current thread. The OpenCL context created with Video Acceleration context attached it (if not attached yet) for optimized GPU data copy between cv::UMat and HW accelerated encoder.
(open-only) Hardware device index (select GPU if multiple available). Device enumeration is acceleration type specific.
If it is not zero, the encoder will expect and encode color frames, otherwise it will work with grayscale frames.
Number of stripes for parallel encoding. -1 for auto detection.
Current quality (0..100%) of the encoded videostream. Can be adjusted dynamically in some codecs.
Prefer to use H/W acceleration. If no one supported, then fallback to software processing.
DirectX 11
libmfx (Intel MediaSDK/oneVPL)
Do not require any specific H/W acceleration, prefer software processing. Reading of this value means that special H/W accelerated handling is not added or not detected by OpenCV.
Traits
Class for video capturing from video files, image sequences or cameras.
Video writer class.
Functions
Returns backend API name or “UnknownVideoAPI(xxx)”
Returns list of all available backends
Returns description and ABI/API version of videoio plugin’s camera interface
Returns list of available backends which works via cv::VideoCapture(int index)
Returns description and ABI/API version of videoio plugin’s stream capture interface
Returns list of available backends which works via cv::VideoCapture(filename)
Returns description and ABI/API version of videoio plugin’s writer interface
Returns list of available backends which works via cv::VideoWriter()
Returns true if backend is available
Returns true if backend is built in (false if backend is used as plugin)