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Example Code
Code and Documents
Attachment
Overview
Very simple video capture and preview example. While obsolete by today's standards and might not be supported in future versions of windows (works fine on W7 32/64 bit and below), can be still usefull when simple frame grabbing required for quick inspection, OCR and such.
For more advanced video capturing needs native DirectShow required, which is on its way to be replaced by media foundation...
The windows you create by using the AVICap window class (avicap32.dll) can perform the following tasks:
- Capture audio and video streams to an audo-video interleaved (AVI) file.
- Connect and disconnect video and audio input devices dynamically.
- View a live incoming video signal by using the overlay or preview methods.
- Specify a file to use when capturing and copy the contents of the capture file to another file.
- Set the capture rate.
- Display dialog boxes that control the video source and format.
- Create, save, and load palettes.
- Copy images and palettes to the clipboard.
- Capture and save a single image as a device-independent bitmap (DIB).
Description
Features:
Attached library provides guide lines and working example on following:
- How to capture video with just couple clicks
- How to get capture device name from registry
- How retrieve image from clipboard and convert it to LabVIEW's image data
- How to specify video format not listed by built-in dialogs but supported by camera
Cons:
- native dialog doesn't support resolutions above 640x480
- no editing capabilities for incoming frames
- no feedback for actual frame rate (as result recorded framerate maybe inaccurate)
- two-step video capture, capture->export (reflects older harddrives performance)
- works with last or default capture device (selective or multiple devices interface maybe difficult to build)
- no audio mixing, i.e. audio from devices with built-in audio only
Pros:
- Easy to use dialogs
- Built-in tolerance on device connect/disconnect (USB cord pulling)
- Ability to specify and tune available video compressors
- Dual mode (file and memory) frame grabbing support
Steps to Implement or Execute Code
Open WM_CAP - AM Capture.vi from attached llb. library and click "RUN" button.
Requirements to Run
Software
- LabVIEW 11.0 or later
Hardware
- Capture device
Additional Images
-Artur
Example code from the Example Code Exchange in the NI Community is licensed with the MIT license.
