This class defines a video input device. More...

#include <videoio.h>

Inheritance diagram for PVideoInputDevice:

Collaboration diagram for PVideoInputDevice:

Classes
class	Capabilities

Public Types
enum	ControlMode { AutomaticControl, AbsoluteControl, RelativeControl, ResetControl }

Public Member Functions
	~PVideoInputDevice ()
	Create a new video input device. More...

virtual bool	GetDeviceCapabilities (Capabilities *capabilities) const
	Retrieve a list of Device Capabilities. More...

virtual PBoolean	Open (const PString &deviceName, PBoolean startImmediate=true)=0
	Open the device given the device name. More...

virtual PBoolean	Close ()
	Close the device. More...

virtual PBoolean	CanCaptureVideo () const
	Is the device a camera, and obtain video. More...

virtual PBoolean	IsCapturing ()=0
	Determine if the video device I/O capture is in progress. More...

virtual PBoolean	SetNearestFrameSize (unsigned width, unsigned height)
	Set the nearest available frame size to be used. More...

virtual PBoolean	GetFrame (PBYTEArray &frame)
	Grab a frame. More...

virtual PBoolean	GetFrameData (BYTE buffer, PINDEX bytesReturned, bool &keyFrame)
	Grab a frame, after a delay as specified by the frame rate. More...

virtual PBoolean	GetFrameData (BYTE buffer, PINDEX bytesReturned=NULL)=0

virtual PBoolean	GetFrameDataNoDelay (BYTE buffer, PINDEX bytesReturned, bool &keyFrame)
	Grab a frame. More...

virtual PBoolean	GetFrameDataNoDelay (BYTE buffer, PINDEX bytesReturned=NULL)=0

virtual bool	FlowControl (const void *flowData)
	Pass data to the inputdevice for flowControl determination. More...

virtual bool	SetCaptureMode (unsigned mode)
	Set the capture modes for implementations that support them. More...

virtual int	GetCaptureMode () const
	Returns the current capture mode. More...

virtual bool	SetControl (PVideoControlInfo::Types type, int value, ControlMode mode)

virtual const PVideoControlInfo &	GetControlInfo (PVideoControlInfo::Types type) const

Public Member Functions inherited from PVideoDevice
virtual	~PVideoDevice ()
	Delete structures created by PVideoDevice();. More...

	P_DECLARE_STREAMABLE_ENUM (VideoFormat, PAL, NTSC, SECAM, Auto)

const PString &	GetDeviceName () const
	Get the device name of the open device. More...

virtual PStringArray	GetDeviceNames () const =0
	Get a list of all of the drivers available. More...

virtual PBoolean	OpenFull (const OpenArgs &args, PBoolean startImmediate=true)
	Open the device given the device name. More...

virtual PBoolean	IsOpen ()=0
	Determine if the device is currently open. More...

virtual PBoolean	Start ()=0
	Start the video device I/O capture. More...

virtual PBoolean	Stop ()=0
	Stop the video device I/O capture. More...

virtual PBoolean	SetVideoFormat (VideoFormat videoFormat)
	Set the video format to be used. More...

virtual VideoFormat	GetVideoFormat () const
	Get the video format being used. More...

virtual int	GetNumChannels ()
	Get the number of video channels available on the device. More...

virtual PStringArray	GetChannelNames ()
	Get the names of video channels available on the device. More...

virtual PBoolean	SetChannel (int channelNumber)
	Set the video channel to be used on the device. More...

virtual int	GetChannel () const
	Get the video channel to be used on the device. More...

virtual bool	SetFrameInfoConverter (const PVideoFrameInfo &info)
	Set the frame info to be used, trying converters if available. More...

virtual PBoolean	SetColourFormatConverter (const PString &colourFormat)
	Set the colour format to be used, trying converters if available. More...

virtual PBoolean	GetVFlipState ()
	Get the video conversion vertical flip state. More...

virtual PBoolean	SetVFlipState (PBoolean newVFlipState)
	Set the video conversion vertical flip state. More...

virtual PBoolean	GetFrameSizeLimits (unsigned &minWidth, unsigned &minHeight, unsigned &maxWidth, unsigned &maxHeight)
	Get the minimum & maximum size of a frame on the device. More...

virtual PBoolean	SetFrameSizeConverter (unsigned width, unsigned height, ResizeMode resizeMode=eMaxResizeMode)
	Set the frame size to be used, trying converters if available. More...

virtual PBoolean	SetFrameSizeConverter (unsigned width, unsigned height, PBoolean)
	Set the frame size to be used, trying converters if available. More...

virtual PBoolean	SetFrameSize (unsigned width, unsigned height)
	Set the frame size to be used. More...

virtual PBoolean	GetFrameSize (unsigned &width, unsigned &height) const
	Get the frame size being used. More...

virtual const PString &	GetColourFormat () const
	Get the colour format being used. More...

virtual PINDEX	GetMaxFrameBytes ()=0
	Get the maximum frame size in bytes. More...

int	GetLastError () const
	Get the last error code. More...

virtual bool	GetAttributes (Attributes &attributes)
	Get video attributes. More...

virtual bool	SetAttributes (const Attributes &attributes)
	Set video attributes. More...

virtual PBoolean	SetVideoChannelFormat (int channelNumber, VideoFormat videoFormat)
	Set VideoFormat and VideoChannel in one ioctl. More...

void	SetPreferredColourFormat (const PString &colourFmt)
	Set preferred native colour format from video capture device. More...

const PString &	GetPreferredColourFormat ()
	Get preferred native colour format from video capture device. More...

Public Member Functions inherited from PVideoFrameInfo
	P_DECLARE_ENUM_EX (ResizeMode, eMaxResizeMode, eScale, 0, eCropCentre, eCropTopLeft)

	PVideoFrameInfo ()
	Construct video frame information. More...

	PVideoFrameInfo (unsigned frameWidth, unsigned frameHeight, const PString &colourFormat="YUV420P", unsigned frameRate=15, ResizeMode resizeMode=eScale)

virtual Comparison	Compare (const PObject &obj) const
	Compare the two PVideoFrameInfo and return their relative rank. More...

virtual void	PrintOn (ostream &strm) const
	Output the contents of the object to the stream. More...

virtual unsigned	GetFrameWidth () const
	Get the width of the frame being used. More...

virtual unsigned	GetFrameHeight () const
	Get the height of the frame being used. More...

virtual PBoolean	SetFrameSar (unsigned width, unsigned height)
	Set the Storage Aspect Ratio size to be used. More...

virtual PBoolean	GetSarSize (unsigned &width, unsigned &height) const
	Get the Storage Aspect Ratio size being used. More...

virtual unsigned	GetSarWidth () const
	Get the width of the Storage Aspect Ratio being used. More...

virtual unsigned	GetSarHeight () const
	Get the height of the Storage Aspect Ratio being used. More...

virtual PBoolean	SetFrameRate (unsigned rate)
	Set the video frame rate to be used on the device. More...

virtual unsigned	GetFrameRate () const
	Get the video frame rate used on the device. More...

virtual PBoolean	SetColourFormat (const PString &colourFormat)
	Set the colour format to be used. More...

void	SetResizeMode (ResizeMode mode)
	Set the resize mode to be used. More...

ResizeMode	GetResizeMode () const
	Get the resize mode to be used. More...

PINDEX	CalculateFrameBytes () const
	Get the number of bytes of an image, given a particular width, height and colour format. More...

bool	Parse (const PString &str)
	Parse a descriptor string for the video format. More...

Public Member Functions inherited from PObject
unsigned	GetTraceContextIdentifier () const
	Get PTRACE context identifier. More...

void	SetTraceContextIdentifier (unsigned id)

void	GetTraceContextIdentifier (PObject &obj)

void	GetTraceContextIdentifier (PObject *obj)

void	SetTraceContextIdentifier (const PObject &obj)

void	SetTraceContextIdentifier (const PObject *obj)

virtual	~PObject ()

virtual PObject *	Clone () const
	Create a copy of the class on the heap. More...

template<class CLS >
CLS *	CloneAs () const
	As for Clone() but converts to specified type. More...

virtual PINDEX	HashFunction () const
	This function yields a hash value required by the `PDictionary` class. More...

virtual const char *	GetClass (unsigned ancestor=0) const
	Get the current dynamic type of the object instance. More...

PBoolean	IsClass (const char *cls) const

virtual PBoolean	InternalIsDescendant (const char *clsName) const
	Determine if the dynamic type of the current instance is a descendent of the specified class. More...

__inline const PObject *	PTraceObjectInstance () const

virtual Comparison	CompareObjectMemoryDirect (const PObject &obj) const
	Determine the byte wise comparison of two objects. More...

bool	operator== (const PObject &obj) const
	Compare the two objects. More...

bool	operator!= (const PObject &obj) const
	Compare the two objects. More...

bool	operator< (const PObject &obj) const
	Compare the two objects. More...

bool	operator> (const PObject &obj) const
	Compare the two objects. More...

bool	operator<= (const PObject &obj) const
	Compare the two objects. More...

bool	operator>= (const PObject &obj) const
	Compare the two objects. More...

virtual void	PrintOn (ostream &strm) const
	Output the contents of the object to the stream. More...

virtual void	ReadFrom (istream &strm)
	Input the contents of the object from the stream. More...

Static Public Member Functions
static PStringArray	GetDriverNames (PPluginManager *pluginMgr=NULL)
	Get the list of available video input drivers (plug-ins) More...

static PStringArray	GetDriversDeviceNames (const PString &driverName, PPluginManager *pluginMgr=NULL)
	Get video input devices that correspond to the specified driver name. More...

static PVideoInputDevice *	CreateDevice (const PString &driverName, PPluginManager *pluginMgr=NULL)
	Create the video input device that corresponds to the specified driver name. More...

static PVideoInputDevice *	CreateDeviceByName (const PString &deviceName, const PString &driverName=PString::Empty(), PPluginManager *pluginMgr=NULL)

static PVideoInputDevice *	CreateOpenedDevice (const PString &driverName, const PString &deviceName, PBoolean startImmediate=true, PPluginManager *pluginMgr=NULL)
	Create an opened video input device that corresponds to the specified names. More...

static PVideoInputDevice *	CreateOpenedDevice (const OpenArgs &args, PBoolean startImmediate=true)
	Create an opened video output device that corresponds to the specified arguments. More...

static bool	GetDeviceCapabilities (const PString &deviceName, Capabilities capabilities, PPluginManager pluginMgr=NULL)
	Retrieve a list of Device Capabilities for particular device. More...

static bool	GetDeviceCapabilities (const PString &deviceName, const PString &driverName, Capabilities caps, PPluginManager pluginMgr=NULL)
	Retrieve a list of Device Capabilities for a particular driver. More...

Protected Attributes
PVideoControlInfo	m_controlInfo [PVideoControlInfo::NumTypes]

Protected Attributes inherited from PVideoDevice
PCaselessString	deviceName

int	lastError

VideoFormat	videoFormat

int	channelNumber

PString	preferredColourFormat

PBoolean	nativeVerticalFlip

PColourConverter *	converter

PBYTEArray	frameStore

Protected Attributes inherited from PVideoFrameInfo
unsigned	frameWidth

unsigned	frameHeight

unsigned	sarWidth

unsigned	sarHeight

unsigned	frameRate

PString	colourFormat

ResizeMode	resizeMode

Protected Attributes inherited from PObject
unsigned	m_traceContextIdentifier

Additional Inherited Members
Protected Member Functions inherited from PVideoDevice
	PVideoDevice ()
	Create a new video device (input or output). More...

PINDEX	GetMaxFrameBytesConverted (PINDEX rawFrameBytes) const

PString	GetDeviceNameFromOpenArgs (const OpenArgs &args) const

Friends inherited from PObject

Detailed Description

This class defines a video input device.

Member Enumeration Documentation

enum PVideoInputDevice::ControlMode

Enumerator
AutomaticControl
AbsoluteControl
RelativeControl
ResetControl

Constructor & Destructor Documentation

PVideoInputDevice::~PVideoInputDevice ( )

inline

Create a new video input device.

Close the video input device on destruction.

References Close().

Member Function Documentation

virtual PBoolean PVideoInputDevice::CanCaptureVideo ( ) const

virtual

Is the device a camera, and obtain video.

Implements PVideoDevice.

virtual PBoolean PVideoInputDevice::Close ( )

inlinevirtual

Close the device.

Implements PVideoDevice.

Reimplemented in PVideoInput1394DcDevice.

Referenced by ~PVideoInputDevice().

static PVideoInputDevice* PVideoInputDevice::CreateDevice	(	const PString &	driverName,
		PPluginManager *	pluginMgr = `NULL`
	)

static

Create the video input device that corresponds to the specified driver name.

Parameters

driverName	Name of driver
pluginMgr	Plug in manager, use default if NULL

static PVideoInputDevice* PVideoInputDevice::CreateDeviceByName	(	const PString &	deviceName,
		const PString &	driverName = `PString::Empty()`,
		PPluginManager *	pluginMgr = `NULL`
	)

static

Parameters

deviceName	Name of device
driverName	Name of driver (if any)
pluginMgr	Plug in manager, use default if NULL

static PVideoInputDevice* PVideoInputDevice::CreateOpenedDevice	(	const PString &	driverName,
		const PString &	deviceName,
		PBoolean	startImmediate = `true`,
		PPluginManager *	pluginMgr = `NULL`
	)

static

Create an opened video input device that corresponds to the specified names.

If the driverName parameter is an empty string or "*" then CreateDeviceByName is used with the deviceName parameter which is assumed to be a value returned from GetDriversDeviceNames().

Parameters

driverName	Name of driver
deviceName	Name of device
startImmediate	Immediately start grabbing
pluginMgr	Plug in manager, use default if NULL

static PVideoInputDevice* PVideoInputDevice::CreateOpenedDevice	(	const OpenArgs &	args,
		PBoolean	startImmediate = `true`
	)

static

Create an opened video output device that corresponds to the specified arguments.

Parameters

args	Parameters to set on opened device
startImmediate	Immediately start display

virtual bool PVideoInputDevice::FlowControl ( const void * flowData )

virtual

Pass data to the inputdevice for flowControl determination.

virtual int PVideoInputDevice::GetCaptureMode ( ) const

virtual

Returns the current capture mode.

See SetCaptureMode() for more details. A return value of -1 indicates an error or the mode is not supported.

virtual const PVideoControlInfo& PVideoInputDevice::GetControlInfo ( PVideoControlInfo::Types type ) const

inlinevirtual

References m_controlInfo.

virtual bool PVideoInputDevice::GetDeviceCapabilities ( Capabilities * capabilities ) const

virtual

Retrieve a list of Device Capabilities.

Parameters

capabilities List of supported capabilities

static bool PVideoInputDevice::GetDeviceCapabilities	(	const PString &	deviceName,
		Capabilities *	capabilities,
		PPluginManager *	pluginMgr = `NULL`
	)

static

Retrieve a list of Device Capabilities for particular device.

Parameters

deviceName	Name of device
capabilities	List of supported capabilities
pluginMgr	Plug in manager, use default if NULL

static bool PVideoInputDevice::GetDeviceCapabilities	(	const PString &	deviceName,
		const PString &	driverName,
		Capabilities *	caps,
		PPluginManager *	pluginMgr = `NULL`
	)

static

Retrieve a list of Device Capabilities for a particular driver.

Parameters

deviceName	Name of device
driverName	Device Driver
caps	List of supported capabilities
pluginMgr	Plug in manager, use default if NULL

static PStringArray PVideoInputDevice::GetDriverNames ( PPluginManager * pluginMgr = NULL )

static

Get the list of available video input drivers (plug-ins)

Parameters

pluginMgr Plug in manager, use default if NULL

static PStringArray PVideoInputDevice::GetDriversDeviceNames	(	const PString &	driverName,
		PPluginManager *	pluginMgr = `NULL`
	)

static

Get video input devices that correspond to the specified driver name.

If driverName is an empty string or the value "*" then this will return a list of unique device names across all of the available drivers. If two drivers have identical names for devices, then the string returned will be of the form driver+'\t'+device.

Parameters

driverName	Name of driver
pluginMgr	Plug in manager, use default if NULL

virtual PBoolean PVideoInputDevice::GetFrame ( PBYTEArray & frame )

virtual

Grab a frame.

virtual PBoolean PVideoInputDevice::GetFrameData	(	BYTE *	buffer,
		PINDEX *	bytesReturned,
		bool &	keyFrame
	)

virtual

Grab a frame, after a delay as specified by the frame rate.

Parameters

buffer	Buffer to receive frame
bytesReturned	Optional bytes returned.
keyFrame	On input, forces generation of key frame, On return indicates key frame generated

virtual PBoolean PVideoInputDevice::GetFrameData	(	BYTE *	buffer,
		PINDEX *	bytesReturned = `NULL`
	)

pure virtual

Parameters

buffer	Buffer to receive frame
bytesReturned	Optional bytes returned.

Implemented in PVideoInput1394DcDevice.

virtual PBoolean PVideoInputDevice::GetFrameDataNoDelay	(	BYTE *	buffer,
		PINDEX *	bytesReturned,
		bool &	keyFrame
	)

virtual

Grab a frame.

Do not delay according to the current frame rate parameter.

Parameters

buffer	Buffer to receive frame
bytesReturned	Optional bytes returned.
keyFrame	On input, forces generation of key frame, On return indicates key frame generated

virtual PBoolean PVideoInputDevice::GetFrameDataNoDelay	(	BYTE *	buffer,
		PINDEX *	bytesReturned = `NULL`
	)

pure virtual

Parameters

buffer	Buffer to receive frame
bytesReturned	Optional bytes returned.

Implemented in PVideoInput1394DcDevice.

virtual PBoolean PVideoInputDevice::IsCapturing ( )

pure virtual

Determine if the video device I/O capture is in progress.

Implemented in PVideoInput1394DcDevice.

virtual PBoolean PVideoInputDevice::Open	(	const PString &	deviceName,
		PBoolean	startImmediate = `true`
	)

pure virtual

Open the device given the device name.

Parameters

deviceName	Device name to open
startImmediate	Immediately start device

Implements PVideoDevice.

Implemented in PVideoInput1394DcDevice.

virtual bool PVideoInputDevice::SetCaptureMode ( unsigned mode )

virtual

Set the capture modes for implementations that support them.

For example with Video For Windows, this is used to select picture (0) or video (1) modes.

In picture-mode the implementation requests a single frame from the connected camera device. The camera device then does nothing until the frame has been processed and the next is requested.

In video-mode the camera continuously sends new frames.

The default implementation does nothing but returns false.

virtual bool PVideoInputDevice::SetControl	(	PVideoControlInfo::Types	type,
		int	value,
		ControlMode	mode
	)

virtual

virtual PBoolean PVideoInputDevice::SetNearestFrameSize	(	unsigned	width,
		unsigned	height
	)

virtual

Set the nearest available frame size to be used.

Note that devices may not be able to produce the requested size, so this function picks the nearest available size.

Default behaviour simply calls SetFrameSize().

Parameters

width	New width of frame
height	New height of frame

Reimplemented from PVideoDevice.

Member Data Documentation

PVideoControlInfo PVideoInputDevice::m_controlInfo[PVideoControlInfo::NumTypes]

protected

Referenced by GetControlInfo().

The documentation for this class was generated from the following file:

videoio.h

Classes

Public Types

Public Member Functions

Static Public Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation