PXL_RETURN_CODE PxLSetStreamState ( HANDLE hCamera, U32 streamState );
This function determines the operating state of the video stream coming from the camera.
- hCamera is the camera handle. This value is returned by PxLInitialize.
- streamState is the new stream state. Valid stream flags are:
- START_STREAM—The stream is running.
- PAUSE_STREAM— Resources are allocated for the stream window. The stream, however, is not running and the host CPU is minimizing CPU cycles on this task.
- STOP_STREAM—The stream is stopped and no resources are allocated.
These values are defined in the file PixeLINKTypes.h.
Comments, Restrictions and Limitations
Frame Time and Frame Number
On Firewire cameras, starting streaming resets the frame time and frame number to zero. i.e. after starting streaming, the first image received from the camera will have a frame descriptor with the fFrameTime and uFrameNumber fields set to zero. This is not true for USB cameras; frame time and number are zero when receiving the first image after being powered on, and will not be reset when streaming is stopped.
For PL-D and PL-X cameras, frame number is reset to zero when the stream is started. Frame time is set to 0 once -- the first time streaming is started -- and is not reset until the camera is power cycled.
Changing Camera Features While Streaming
Most features may be changed while the camera is streaming, however the following features require the stream to be paused or stopped:
For more information, please see the note at the bottom of the Features page. You can also find more information in the article for a particular feature.