Struct opencv::videoio::VideoCapture

pub struct VideoCapture { /* fields omitted */ }

Class for video capturing from video files, image sequences or cameras.

The class provides C++ API for capturing video from cameras or for reading video files and image sequences.

Here is how the class can be used: @include samples/cpp/videocapture_basic.cpp

Note: In @ref videoio_c "C API" the black-box structure CvCapture is used instead of %VideoCapture.

Note:

• (C++) A basic sample on using the %VideoCapture interface can be found at OPENCV_SOURCE_CODE/samples/cpp/videocapture_starter.cpp
• (Python) A basic sample on using the %VideoCapture interface can be found at OPENCV_SOURCE_CODE/samples/python/video.py
• (Python) A multi threaded video processing sample can be found at OPENCV_SOURCE_CODE/samples/python/video_threaded.py
• (Python) %VideoCapture sample showcasing some features of the Video4Linux2 backend OPENCV_SOURCE_CODE/samples/python/video_v4l2.py

Implementations

impl VideoCapture

pub fn as_raw_VideoCapture(&self) -> *const c_void

pub fn as_raw_mut_VideoCapture(&mut self) -> *mut c_void

impl VideoCapture

pub fn default() -> Result<VideoCapture>

Default constructor

Note: In @ref videoio_c "C API", when you finished working with video, release CvCapture structure with cvReleaseCapture(), or use Ptr<CvCapture> that calls cvReleaseCapture() automatically in the destructor.

pub fn from_file(filename: &str, api_preference: i32) -> Result<VideoCapture>

Default constructor

Note: In @ref videoio_c "C API", when you finished working with video, release CvCapture structure with cvReleaseCapture(), or use Ptr<CvCapture> that calls cvReleaseCapture() automatically in the destructor.

Overloaded parameters

 Opens a video file or a capturing device or an IP video stream for video capturing with API Preference

Parameters

• filename: it can be:
  • name of video file (eg. video.avi)
  • or image sequence (eg. img_%02d.jpg, which will read samples like img_00.jpg, img_01.jpg, img_02.jpg, ...)
  • or URL of video stream (eg. protocol://host:port/script_name?script_params|auth)
  • or GStreamer pipeline string in gst-launch tool format in case if GStreamer is used as backend Note that each video stream or IP camera feed has its own URL scheme. Please refer to the documentation of source stream to know the right URL.
• apiPreference: preferred Capture API backends to use. Can be used to enforce a specific reader implementation if multiple are available: e.g. cv::CAP_FFMPEG or cv::CAP_IMAGES or cv::CAP_DSHOW.

See also

cv::VideoCaptureAPIs

C++ default parameters

• api_preference: CAP_ANY

pub fn new(index: i32, api_preference: i32) -> Result<VideoCapture>

Default constructor

Note: In @ref videoio_c "C API", when you finished working with video, release CvCapture structure with cvReleaseCapture(), or use Ptr<CvCapture> that calls cvReleaseCapture() automatically in the destructor.

Overloaded parameters

 Opens a camera for video capturing

Parameters

• index: id of the video capturing device to open. To open default camera using default backend just pass 0. (to backward compatibility usage of camera_id + domain_offset (CAP_*) is valid when apiPreference is CAP_ANY)
• apiPreference: preferred Capture API backends to use. Can be used to enforce a specific reader implementation if multiple are available: e.g. cv::CAP_DSHOW or cv::CAP_MSMF or cv::CAP_V4L.

See also

cv::VideoCaptureAPIs

C++ default parameters

• api_preference: CAP_ANY

pub fn wait_any(
    streams: &Vector<VideoCapture>,
    ready_index: &mut Vector<i32>,
    timeout_ns: i64
) -> Result<bool>

Wait for ready frames from VideoCapture.

Parameters

• streams: input video streams
• readyIndex: stream indexes with grabbed frames (ready to use .retrieve() to fetch actual frame)
• timeoutNs: number of nanoseconds (0 - infinite)

Returns

true if streamReady is not empty

@throws Exception %Exception on stream errors (check .isOpened() to filter out malformed streams) or VideoCapture type is not supported

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.

C++ default parameters

• timeout_ns: 0

Trait Implementations

impl Boxed for VideoCapture

pub unsafe fn from_raw(ptr: *mut c_void) -> Self

Wrap the specified raw pointer

pub fn into_raw(self) -> *mut c_void

Return an the underlying raw pointer while consuming this wrapper.

pub fn as_raw(&self) -> *const c_void

Return the underlying raw pointer.

pub fn as_raw_mut(&mut self) -> *mut c_void

Return the underlying mutable raw pointer

impl Drop for VideoCapture

pub fn drop(&mut self)

Executes the destructor for this type.

impl Send for VideoCapture

impl VectorElement for VideoCapture where
    Vector<VideoCapture>: VectorExtern<VideoCapture>, 

pub fn opencv_vector_to_vec(v: &Vector<VideoCapture>) -> Vec<VideoCapture>

impl VideoCaptureTrait for VideoCapture

pub fn as_raw_VideoCapture(&self) -> *const c_void

pub fn as_raw_mut_VideoCapture(&mut self) -> *mut c_void

pub fn open_file(&mut self, filename: &str, api_preference: i32) -> Result<bool>

Opens a video file or a capturing device or an IP video stream for video capturing.

pub fn open(&mut self, index: i32, api_preference: i32) -> Result<bool>

Opens a camera for video capturing

pub fn is_opened(&self) -> Result<bool>

Returns true if video capturing has been initialized already.

pub fn release(&mut self) -> Result<()>

Closes video file or capturing device.

pub fn grab(&mut self) -> Result<bool>

Grabs the next frame from video file or capturing device.

pub fn retrieve(
    &mut self,
    image: &mut dyn ToOutputArray,
    flag: i32
) -> Result<bool>

Decodes and returns the grabbed video frame.

pub fn read(&mut self, image: &mut dyn ToOutputArray) -> Result<bool>

Grabs, decodes and returns the next video frame.

pub fn set(&mut self, prop_id: i32, value: f64) -> Result<bool>

Sets a property in the VideoCapture.

pub fn get(&self, prop_id: i32) -> Result<f64>

Returns the specified VideoCapture property

pub fn get_backend_name(&self) -> Result<String>

Returns used backend API name

pub fn set_exception_mode(&mut self, enable: bool) -> Result<()>

Switches exceptions mode

pub fn get_exception_mode(&mut self) -> Result<bool>

query if exception mode is active