InputVideoQT

Module used for grabbing images from a video source using QuickTime such as iSight or a DV camera with FireWire. The module only works with OS X. If sizes are are set the module requests that the image be scaled to that size. The module operates in asynchronous mode, which means that the image retreived is the previous one. Ikaros continues to run while the next image is transferred from the camera and the module gets it at the next tick. This can appear confusing when Ikaros is single steped from the viewer. The mode parameter is used to determine whether to use preview mode or not. The lag may be lower in preview but the image quiality can become lower. See the QTKit documentation for details. By setting the device_id parameter. The module will receive input from that particular device. If the device_id is not set, the module will connect to the default device. The device id has the form " 0xa27000413a443-video" (note that it starts with a space). The space may be a bug in OX X and it is recommended that the space is not included in the string since Ikaros will add it if it cannot open the device with the supplied name. The device_id for the found default device is printed when Ikaros is starting up. It can also be found in the System Information application by looking up the GUID for the device and adding "-video" to it.

Example XML definition

A simple example

  <module
      class = "InputVideoQT"
      name = "VideoSource"
      size_x = "640"
      size_y = "480"
  />

Parameters

Name	Description	Type	Default
class	The class name for the module; must be "InputVideoQT".	string
name	The name of this instance of the module.	string
size_x	Size of the grabbed frame	int	160
size_y	Size of the grabbed frame	int	120
flip	Should the image be flipped	bool	no
mode	Capture mode. Preview may reduce lag but may also reduce image quality.	choices: standard preview	standard
device_id	Use a camera with a particular ID	string
list_devices	List the device ids of available devices on start-up	bool	no

Module Connections

Outputs

Name	Description
INTENSITY	The intensity of the image
RED	The red channel of the image
GREEN	The green channel of the image
BLUE	The blue channel of the image

Limitations

It should be possible to run the module also in synchronous mode, where the module would wait for each new frame before continuing.

Bugs

The code uses a temporary solution to work around that TIFFRepresentation is not thread safe. This is actually a bug in Cocoa.

Author

Christian Balkenius
christian.balkenius@lucs.lu.se
Lund University Cognitive Science

Files

InputVideoQT.h
InputVideoQT.cc
InputVideoQT.ikc