Struct opencv::videoio::VideoCapture
source · [−]pub struct VideoCapture { /* private fields */ }Expand description
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
sourceimpl VideoCapture
impl VideoCapture
sourcepub fn default() -> Result<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.
sourcepub fn from_file(filename: &str, api_preference: i32) -> Result<VideoCapture>
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 likeimg_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.
- name of video file (eg.
- 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
sourcepub fn from_file_with_params(
filename: &str,
api_preference: i32,
params: &Vector<i32>
) -> Result<VideoCapture>
pub fn from_file_with_params(
filename: &str,
api_preference: i32,
params: &Vector<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 and parameters
The params parameter allows to specify extra parameters encoded as pairs (paramId_1, paramValue_1, paramId_2, paramValue_2, ...).
See cv::VideoCaptureProperties
sourcepub fn new(index: i32, api_preference: i32) -> Result<VideoCapture>
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
sourcepub fn new_with_params(
index: i32,
api_preference: i32,
params: &Vector<i32>
) -> Result<VideoCapture>
pub fn new_with_params(
index: i32,
api_preference: i32,
params: &Vector<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 with API Preference and parameters
The params parameter allows to specify extra parameters encoded as pairs (paramId_1, paramValue_1, paramId_2, paramValue_2, ...).
See cv::VideoCaptureProperties
sourcepub fn wait_any(
streams: &Vector<VideoCapture>,
ready_index: &mut Vector<i32>,
timeout_ns: i64
) -> Result<bool>
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