VideoWrapper.cpp File Reference

Provides an interface adapter for multiple video capture APIs. More...

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "VideoWrapper.h"
#include "VideoWrapperTypes.h"
#include "VideoWrapperTime.h"
#include "VideoWrapperCaptureReplay.h"

Functions
VWResult	VIDEO_setPrintFunction (VWPrintFcn *func)
	Sets a callback function that may be used for printing messages from the video libraries.
VWResult	VIDEO_loadLibrary (char *szLibIdentifier, char *szLibImplementation)
	Dynamically loads support for a camera library.
VWResult	VIDEO_openVideo (char *lpCmdLine, VWHVideo *phVideo)
	Intializes a video camera.
VWResult	VIDEO_close (VWHVideo hVideo)
	Close the video camera.
VWResult	VIDEO_startVideo (VWHVideo hVideo)
	Starts aquiring frames from the camera.
VWResult	VIDEO_stopVideo (VWHVideo hVideo)
	Stops aquiring frames from the camera.
VWResult	VIDEO_getFrame (VWHVideo hVideo, unsigned char **ppbFrame, timeval *pTimestamp=NULL)
	Polls for new video frame.
VWResult	VIDEO_releaseFrame (VWHVideo hVideo)
	Releases the frame so that memory may be deallocated.
VWResult	VIDEO_resetVideo (VWHVideo hVideo, VWBool bAutomatic)
	Resets all the camera parameters to defaults.
VWResult	VIDEO_showPropertiesDialog (VWHVideo hVideo)
	Displays the a pop-up property window associated with this device.
VWResult	VIDEO_getWidth (VWHVideo hVideo, int *pnWidth)
	Gets the video width.
VWResult	VIDEO_getHeight (VWHVideo hVideo, int *pnHeight)
	Gets the video height.
VWResult	VIDEO_getDepth (VWHVideo hVideo, int *pnDepth)
	Gets color depth as bits per pixel.
VWResult	VIDEO_getFrameRate (VWHVideo hVideo, double *pFrameRate)
	Gets the frame rate of the camera as frames per second.
VWResult	VIDEO_setPropertyLong (VWHVideo hVideo, VWCamProp propId, long lValue1, long lValue2, VWBool bAuto)
	Sets a long-typed camera property such as white balance, gain, etc.
VWResult	VIDEO_getPropertyLong (VWHVideo hVideo, VWCamProp propId, long *plValue1, long *plValue2, VWBool *pbAuto)
	Gets a long-typed camera property such as white balance, gain, etc.
VWResult	VIDEO_getPropertyRangeLong (VWHVideo hVideo, VWCamProp propId, long *plMinValue, long *plMaxValue, VWBool *pbAuto)
	Gets the valid range for a long-typed camera property such as white balance, gain, etc.
VWResult	VIDEO_setPropertyString (VWHVideo hVideo, VWCamProp propId, char *szValue)
	Sets a string-typed camera property.
VWResult	VIDEO_getPropertyString (VWHVideo hVideo, VWCamProp propId, char *szValue, int nSize)
	Gets a string-typed camera property.
char *VW_API_ENTRY	VIDEO_getErrDescription (VWResult resultCode)
	Gets a string describing the given VWResult code.
VWResult	VIDEO_replaySetPlaybackPosition (VWHVideo hVideo, timeval tvNewPosition)
	Sets the current position for video playback to permit random access.
VWResult	VIDEO_replaySetPlaybackLoop (VWHVideo hVideo, VWBool bLoop)
	Sets the loop state of the replay camera.
VWResult	VIDEO_replayIsPlaybackFinished (VWHVideo hVideo, VWBool *pbFinished)
	Checks to see if playback is finished.

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Detailed Description

Provides an interface adapter for multiple video capture APIs.

Copyright 2004-5, Georgia Tech Research Corporation, Atlanta, Georgia 30332-0415 All Rights Reserved

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Function Documentation

VWResult VIDEO_close (  VWHVideo  hVideo  )

Close the video camera. Parameters: hVideo  Handle to video camera. Returns: VWResult indicating success or failure.

VWResult VIDEO_getDepth (  VWHVideo  hVideo, int *  pnDepth )

Gets color depth as bits per pixel. Parameters: hVideo  Handle to video camera. [out]  pnDepth  Pointer returning the bits per pixel. Returns: VWResult indicating success or failure.

char* VW_API_ENTRY VIDEO_getErrDescription (  VWResult  resultCode  )

Gets a string describing the given VWResult code. Parameters: resultCode  VWResult code to describe. Returns: A string describing the VWResult code

VWResult VIDEO_getFrame (  VWHVideo  hVideo, unsigned char **  ppbFrame, timeval *  pTimestamp )

Polls for new video frame. Parameters: hVideo  Handle to video camera. [out]  ppbFrame  Pointer returning the captured video frame. Memory is alocated by the camera library. If no frame is availible, ppbFrame returns NULL. [out]  pTimestamp  Pointer returning the timestamp of the captured video frame. Returns: VWResult indicating success or failure.

VWResult VIDEO_getFrameRate (  VWHVideo  hVideo, double *  pdFrameRate )

Gets the frame rate of the camera as frames per second. Parameters: hVideo  Handle to video camera. [out]  pdFrameRate  Pointer returning the frame rate of the camera. Returns: VWResult indicating success or failure.

VWResult VIDEO_getHeight (  VWHVideo  hVideo, int *  pnHeight )

Gets the video height. Parameters: hVideo  Handle to video camera. [out]  pnHeight  Pointer returning the height of the video. Returns: VWResult indicating success or failure.

VWResult VIDEO_getPropertyLong (  VWHVideo  hVideo, VWCamProp  propId, long *  plValue1 = NULL, long *  plValue2 = NULL, VWBool *  pbAuto = NULL )

Gets a long-typed camera property such as white balance, gain, etc. Some properties are composed of two values. Symbols for camera properties are defined in VideoWrapperTypes.h. Parameters: propId  Identifier of the property. [out]  plValue1  Pointer returning first property value. [out]  plValue2  Pointer returning second property value. Not used with most properties. Returns: VWResult indicating success or failure. See also: VWCamProp

VWResult VIDEO_getPropertyRangeLong (  VWHVideo  hVideo, VWCamProp  propId, long *  plMinValue = NULL, long *  plMaxValue = NULL, VWBool *  pbAuto = NULL )

Gets the valid range for a long-typed camera property such as white balance, gain, etc. Symbols for camera properties are defined in VideoWrapperTypes.h. Parameters: propId  Identifier of the property. lValue1  First property value. lValue2  Second property value. Not used with most properties. Returns: VWResult indicating success or failure. See also: VWCamProp

VWResult VIDEO_getPropertyString (  VWHVideo  hVideo, VWCamProp  propId, char *  szValue, int  nSize )

Gets a string-typed camera property. Parameters: propId  Identifier of the property. [in]  szValue  Property value. Returns: VWResult indicating success or failure. See also: VWCamProp

VWResult VIDEO_getWidth (  VWHVideo  hVideo, int *  pnWidth )

Gets the video width. Parameters: hVideo  Handle to video camera. [out]  pnWidth  Pointer returning the width of the video. Returns: VWResult indicating success or failure.

VWResult VIDEO_loadLibrary (  char *  szLibIdentifier, char *  szLibImplementation )

Dynamically loads support for a camera library. Some camera libraries are 'preset' and VideoWrapper can load them automatically, however this function allows VideoWrapper to be extended at runtime to support additional camera libraries. Parameters: [in]  szLibIdentifier  Identifier to represent library in calls to VIDEO_openVideo. [in]  szLibImplementation  Platform-specific implementation string. Windows: File name of DLL implementing support. Apple: Unsupported. Returns: VWResult indicating success or failure.

VWResult VIDEO_openVideo (  char *  szInit, VWHVideo *  phVideo )

Intializes a video camera. Parameters: [in]  szInit  An implementation-dependent string used to configure the camera. Consult the 'VideoWrapper_xxx Details' page for the API adapter you are instantiating for the string format. Generally, however, the string is formatted as follows: "libId: camNum width frameRate colorMode scale outputMode" where libId is the identifier for the API adapter library. camNum is a number (starting at 0) representing the camera to open. width is the desired frame width. frameRate is the desired frame rate colorMode is a string specifying the format of the desired color mode (e.g. rgb, yuv). scale is 0 or 1. 1 means a mode of 2x or 4x the size can be used, and scaled to the correct size. A noteable exception is the "replay" camera library, which will replay video frames that have been previously saved. In this case szInit takes the form: "replay: directory" where replay is the identifier of the replay camera library. directory is the path to the directory containing the saved video frames. [out]  phVideo  Pointer to the handle for opened camera. Returns: VWResult indicating success or failure.

VWResult VIDEO_releaseFrame (  VWHVideo  hVideo  )

Releases the frame so that memory may be deallocated. Parameters: hVideo  Handle to video camera. Returns: VWResult indicating success or failure.

VWResult VIDEO_replayIsPlaybackFinished (  VWHVideo  hVideo, VWBool *  pbFinished )

Checks to see if playback is finished. Will return true after a call to getNextFrame goes past the last saved frame. Parameters: hVideo  Handle to video camera. [out]  pbFinished  Pointer returning TRUE if playback is finished, otherwise FALSE. Returns: VWResult indicating success or failure.

VWResult VIDEO_replaySetPlaybackLoop (  VWHVideo  hVideo, VWBool  bLoop )

Sets the loop state of the replay camera. Has no effect with other camera libraries. If the loop state is true, video playback will loop when the end is reached. Parameters: hVideo  Handle to video camera. bLoop  The new loop state. Returns: VWResult indicating success or failure.

VWResult VIDEO_replaySetPlaybackPosition (  VWHVideo  hVideo, timeval  tvNewPosition )

Sets the current position for video playback to permit random access. Parameters: hVideo  Handle to video camera. tvNewPosition  Time offset from the beginning of the captured video. Returns: VWResult indicating success or failure.

VWResult VIDEO_resetVideo (  VWHVideo  hVideo, VWBool  bAutomatic )

Resets all the camera parameters to defaults. Parameters: hVideo  Handle to video camera. bAutomatic  If true, allow the camera to auto-adust. Returns: VWResult indicating success or failure.

VWResult VIDEO_setPrintFunction (  VWPrintFcn *  fp  )

Sets a callback function that may be used for printing messages from the video libraries. Parameters: function:  ptr to print function

VWResult VIDEO_setPropertyLong (  VWHVideo  hVideo, VWCamProp  propId, long  lValue1, long  lValue2 = 0L, VWBool  bAuto = FALSE )

Sets a long-typed camera property such as white balance, gain, etc. Some properties are composed of two values. Symbols for camera properties are defined in VideoWrapperTypes.h. Parameters: propId  Identifier of the property. lValue1  First property value. lValue2  Second property value. Not used with most properties. Returns: VWResult indicating success or failure. See also: VWCamProp

VWResult VIDEO_setPropertyString (  VWHVideo  hVideo, VWCamProp  propId, char *  szValue )

Sets a string-typed camera property. Parameters: propId  Identifier of the property. [in]  szValue  Property value. Returns: VWResult indicating success or failure. See also: VWCamProp

VWResult VIDEO_showPropertiesDialog (  VWHVideo  hVideo  )

Displays the a pop-up property window associated with this device. Not supported by all camera libraries. Parameters: hVideo  Handle to video camera. Returns: VWResult indicating success or failure.

VWResult VIDEO_startVideo (  VWHVideo  hVideo  )

Starts aquiring frames from the camera. Parameters: hCam  Handle to video camera. Returns: VWResult indicating success or failure.

VWResult VIDEO_stopVideo (  VWHVideo  hVideo  )

Stops aquiring frames from the camera. Parameters: hCam  Handle to video camera. Returns: VWResult indicating success or failure.

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