Open video file or a capturing device or a IP video stream for video capturing

successFlag = cap.open(index)
successFlag = cap.open(filename)
successFlag = cap.open(..., 'API',apiPreference)

Input

• index id of the video capturing device to open. To open default camera using default backend just pass 0.
• 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). 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.
  • or device name (for backends like V4L or gPhoto2)

Output

• successFlag bool, true if the file/camera has been successfully opened.

Options

• API preferred capture API backend to use. Can be used to enforce a specific reader implementation if multiple are available: e.g. 'FFMPEG' or 'Images' or 'DirectShow'. The list of supported API backends:
  • Any Auto detect. This is the default.
  • VfW Video For Windows (platform native).
  • V4L V4L/V4L2 capturing support via libv4l.
  • V4L2 Same as V4L.
  • FireWire IEEE 1394 drivers.
  • FireWare Same as FireWire.
  • IEEE1394 Same as FireWire.
  • DC1394 Same as FireWire.
  • CMU1394 Same as FireWire.
  • QuickTime QuickTime.
  • Unicap Unicap drivers.
  • DirectShow DirectShow (via videoInput).
  • PvAPI PvAPI, Prosilica GigE SDK.
  • OpenNI OpenNI (for Kinect).
  • OpenNIAsus OpenNI (for Asus Xtion).
  • Android Android - not used.
  • XIMEA XIMEA Camera API.
  • AVFoundation AVFoundation framework for iOS (OS X Lion will have the same API).
  • Giganetix Smartek Giganetix GigEVisionSDK.
  • MediaFoundation Microsoft Media Foundation (via videoInput).
  • WinRT Microsoft Windows Runtime using Media Foundation.
  • IntelPerC Intel Perceptual Computing SDK.
  • OpenNI2 OpenNI2 (for Kinect).
  • OpenNI2Asus OpenNI2 (for Asus Xtion and Occipital Structure sensors).
  • gPhoto2 gPhoto2 connection.
  • GStreamer GStreamer.
  • FFMPEG Open video file or stream using the FFMPEG library.
  • Images OpenCV Image Sequence (e.g. img_%02d.jpg).
  • Aravis Aravis GigE SDK.
  • MotionJPEG Built-in OpenCV MotionJPEG codec.
  • MediaSDK Intel MediaSDK.

The method first calls cv.VideoCapture.release to close the already opened file or camera.

Example

Use API option to enforce a specific reader implementation if multiple are available like 'FFMPEG' or 'Images' or 'DirectShow'. For example, to open camera 1 using the "MS Media Foundation" API:

cap.open(1, 'API','MediaFoundation')

Note

Backends are available only if they have been built with your OpenCV binaries. Check your build to know which APIs are currently available. To enable/disable APIs, you have to re-configure OpenCV using the appropriates CMake switches and recompile OpenCV itself.