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 Types inherited from PVideoFrameInfo
enum	StandardSizes { SQCIFWidth = 128, SQCIFHeight = 96, QCIFWidth = 176, QCIFHeight = 144, CIFWidth = 352, CIFHeight = 288, CIF4Width = 704, CIF4Height = 576, CIF16Width = 1408, CIF16Height = 1152, HD480Width = 704, HD480Height = 480, i480Width = 704, i480Height = 480, HD720Width = 1280, HD720Height = 720, p720Width = 1280, p720Height = 720, HD1080Width = 1920, HD1080Height = 1080, i1080Width = 1920, i1080Height = 1080, HDTVWidth = 1920, HDTVHeight = 1080, MaxWidth = 1920, MaxHeight = 1200 }

Public Types inherited from PObject
enum	Comparison { LessThan = -1, EqualTo = 0, GreaterThan = 1 }
	Result of the comparison operation performed by the `Compare()` function. More...

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...

bool	GetFrame (BYTE *buffer, PINDEX &bytesReturned, bool &keyFrame, bool wait=true)
	Grab a frame. More...

virtual PBoolean	GetFrame (PBYTEArray &frame)

virtual PBoolean	GetFrame (PBYTEArray &frame, unsigned &width, unsigned &height)

bool	GetFrameData (BYTE buffer, PINDEX bytesReturned, bool &keyFrame)
	For backward compatibility. More...

bool	GetFrameData (BYTE buffer, PINDEX bytesReturned=NULL)
	For backward compatibility. More...

bool	GetFrameDataNoDelay (BYTE buffer, PINDEX bytesReturned, bool &keyFrame)
	For backward compatibility. More...

bool	GetFrameDataNoDelay (BYTE buffer, PINDEX bytesReturned=NULL)
	For backward compatibility. More...

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...

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

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

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

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

virtual 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...

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

virtual 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, eScaleKeepAspect)

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

	PVideoFrameInfo (unsigned frameWidth, unsigned frameHeight, const PString &colourFormat=PVideoFrameInfo::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 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...

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

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

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

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

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

__inline void	SetTraceContextIdentifier (unsigned id)

__inline void	SetTraceContextIdentifier (const PObject &obj)

__inline void	SetTraceContextIdentifier (const PObject *obj)

__inline void	CopyTraceContextIdentifier (PObject &obj) const

__inline void	CopyTraceContextIdentifier (PObject *obj) const

virtual	~PObject ()

__inline const char *	GetClass () const

__inline bool	IsClass (const char *name) const

__inline const PObject *	PTraceObjectInstance () const

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 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	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, bool startImmediate=true, PPluginManager *pluginMgr=NULL)
	Create an opened video input device that corresponds to the specified names. More...

static PVideoInputDevice *	CreateOpenedDevice (const PString &deviceName, bool startImmediate=true, PPluginManager *pluginMgr=NULL)

static PVideoInputDevice *	CreateOpenedDevice (const OpenArgs &args, bool 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...

static PBoolean	GetInputDeviceCapabilities (const PString &, Capabilities *)

Static Public Member Functions inherited from PVideoFrameInfo
static const PString &	YUV420P ()

static PINDEX	CalculateFrameBytes (unsigned width, unsigned height, const PString &colourFormat=PVideoFrameInfo::YUV420P())

static bool	ParseSize (const PString &str, unsigned &width, unsigned &height)
	Parse the standard size string names. More...

static PString	AsString (unsigned width, unsigned height)
	Get a width/height as a standard size string name. More...

static PStringArray	GetSizeNames ()
	Get all "known" image size names. More...

Static Public Member Functions inherited from PObject
static __inline void	CopyTraceContextIdentifier (PObject &to, const PObject &from)

static __inline void	CopyTraceContextIdentifier (PObject &to, const PObject *from)

static __inline void	CopyTraceContextIdentifier (PObject *to, const PObject &from)

static __inline void	CopyTraceContextIdentifier (PObject to, const PObject from)

static __inline const char *	Class ()

static __inline const PObject *	PTraceObjectInstance (const char *)

static __inline const PObject *	PTraceObjectInstance (const PObject *obj)

template<typename T >
static Comparison	Compare2 (T v1, T v2)
	Compare two types, returning Comparison type. More...

static Comparison	InternalCompareObjectMemoryDirect (const PObject obj1, const PObject obj2, PINDEX size)
	Internal function caled from CompareObjectMemoryDirect() More...

Protected Member Functions
virtual bool	InternalGetFrameData (BYTE *buffer, PINDEX &bytesReturned, bool &keyFrame, bool wait)=0

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

PString	ParseDeviceNameTokenString (const char token, const char defaultValue)

int	ParseDeviceNameTokenInt (const char *token, int defaultValue)

uint64_t	ParseDeviceNameTokenUnsigned (const char *token, uint64_t defaultValue)

Protected Member Functions inherited from PObject
	PObject ()
	Constructor for PObject, made protected so cannot ever create one on its own. More...

Protected Attributes
PVideoControlInfo	m_controlInfo [PVideoControlInfo::NumTypes]

Protected Attributes inherited from PVideoDevice
PCaselessString	m_deviceName

int	m_lastError

VideoFormat	m_videoFormat

int	m_channelNumber

PString	m_preferredColourFormat

bool	m_nativeVerticalFlip

PColourConverter *	m_converter

PBYTEArray	m_frameStore

Protected Attributes inherited from PVideoFrameInfo
unsigned	m_frameWidth

unsigned	m_frameHeight

unsigned	m_sarWidth

unsigned	m_sarHeight

unsigned	m_frameRate

PString	m_colourFormat

ResizeMode	m_resizeMode

Protected Attributes inherited from PObject
unsigned	m_traceContextIdentifier

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 PVideoInputDeviceIndirect, and 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,
		bool	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

Referenced by CreateOpenedDevice().

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

inlinestatic

Parameters

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

References CreateOpenedDevice(), and PString::Empty().

static PVideoInputDevice* PVideoInputDevice::CreateOpenedDevice	(	const OpenArgs &	args,
		bool	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.

Reimplemented in PVideoInputDeviceIndirect.

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.

Reimplemented in PVideoInputDeviceIndirect.

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

Reimplemented in PVideoInputDeviceIndirect.

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

bool PVideoInputDevice::GetFrame	(	BYTE *	buffer,
		PINDEX &	bytesReturned,
		bool &	keyFrame,
		bool	wait = `true`
	)

Grab a frame.

If wait is false, and no frame is available, then the function still returns true, but the bytesReturned will be zero.

Parameters

buffer	Buffer to receive frame
bytesReturned	Bytes returned.
keyFrame	On input, forces generation of key frame, On return indicates key frame generated
wait	Wait for frame to become available

virtual PBoolean PVideoInputDevice::GetFrame ( PBYTEArray & frame )

virtual

virtual PBoolean PVideoInputDevice::GetFrame	(	PBYTEArray &	frame,
		unsigned &	width,
		unsigned &	height
	)

virtual

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

For backward compatibility.

Parameters

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

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

For backward compatibility.

Parameters

buffer	Buffer to receive frame
bytesReturned	Optional bytes returned.

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

For backward compatibility.

Parameters

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

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

For backward compatibility.

Parameters

buffer	Buffer to receive frame
bytesReturned	Optional bytes returned.

static PBoolean PVideoInputDevice::GetInputDeviceCapabilities	(	const PString &	,
		Capabilities *
	)

inlinestatic

virtual bool PVideoInputDevice::InternalGetFrameData	(	BYTE *	buffer,
		PINDEX &	bytesReturned,
		bool &	keyFrame,
		bool	wait
	)

protectedpure virtual

Parameters

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

Implemented in PVideoInputEmulatedDevice, PVideoInputDeviceIndirect, and PVideoInput1394DcDevice.

virtual PBoolean PVideoInputDevice::IsCapturing ( )

pure virtual

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

Implemented in PVideoInputEmulatedDevice, PVideoInputDeviceIndirect, and 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 PVideoInputDeviceIndirect, and 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.

Reimplemented in PVideoInputDeviceIndirect.