Sample Grabber

2005-09-18, GitHub

This library was developed as the part of an emotion recognizer project at the university of Debrecen. To handle a capture device I got myself familiar with the applicable parts of the Windows SDK / DirectShow. Since there was no support to invoke directshow functions from managed code (C#) I also needed a marshall library. I found an almost suitable library at codeproject, however the complexity of the problem required me to revise some of the critical parts of the library. It took a while to circumvent a marshalling problem that was stated to be impossible by many on MSDN…

Two plugins come with the package. The file based (prFile.dll) plugin and the general capture device (prGeneralDev.dll) plugin. The file provider can make use of any file that is renderable with the default graphbuilder. The general device provider can cope with any kind of camera or tuner. Unfortunately it cannot deal with devices that require special codecs like some HD cameras do.

Features

  • All sample providers are plugins
  • Buffered/direct mode. If your device is slow, our your application needs instant reply you can turn on the buffered mode. It keeps a copy of the latest frame accessible to caller processes at any time.
  • Runtime statistics
  • Asynchronuos preview of the input stream
  • Single frame mode/Frame server mode operation. in frame server mode the sampler keeps sending you the images right after your process function has returned.
  • Interactive and scripted startup

video sample grabber