This class defines a video device. More...

#include <videoio.h>

Inheritance diagram for PVideoDevice:

Collaboration diagram for PVideoDevice:

Classes
struct	Attributes

struct	OpenArgs

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

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

virtual PBoolean	Close ()=0
	Close the device. 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	SetNearestFrameSize (unsigned width, unsigned height)
	Set the nearest available frame size to be used. 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 PBoolean	CanCaptureVideo () const =0
	Is the device a camera, and obtain video. 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...

Protected Member Functions
	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
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

Additional Inherited Members
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...

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...

Detailed Description

This class defines a video device.

This class is used to abstract the few parameters that are common to both\ input and output devices.

Example colour formats are:

"Grey" Simple 8 bit linear grey scale "Gray" Synonym for Grey "RGB32" 32 bit RGB "RGB24" 24 bit RGB "RGB565" 16 bit RGB (6 bit green) "RGB555" 15 bit RGB "YUV422" YUV 4:2:2 packed "YUV422P" YUV 4:2:2 planar "YUV411" YUV 4:1:1 packed "YUV411P" YUV 4:1:1 planar "YUV420" YUV 4:2:0 packed "YUV420P" YUV 4:2:0 planar, use PTLIB_VIDEO_YUV420P or PVideoFrameInfo::YUV420P() "YUV410" YUV 4:1:0 packed "YUV410P" YUV 4:1:0 planar "MJPEG" Motion JPEG "UYVY422" YUV 4:2:2 packed as U Y V Y U Y V Y ... "UYV444" YUV 4:4:4 packed as U Y V U Y V ... They are used in IEEE 1394 digital cameras. The specification is found at http://www.1394ta.org/Download/Technology/Specifications/2000/IIDC_Spec_v1_30.pdf

Constructor & Destructor Documentation

PVideoDevice::PVideoDevice ( )

protected

Create a new video device (input or output).

virtual PVideoDevice::~PVideoDevice ( )

virtual

Delete structures created by PVideoDevice();.

Member Function Documentation

virtual PBoolean PVideoDevice::CanCaptureVideo ( ) const

pure virtual

Is the device a camera, and obtain video.

Implemented in PVideoInputDevice, and PVideoOutputDevice.

virtual PBoolean PVideoDevice::Close ( )

pure virtual

Close the device.

Implemented in PVideoInputDeviceIndirect, PVideoInputDevice, PVideoOutputDevice, P_WXWINDOWS_DEVICE_CLASS, and PVideoInput1394DcDevice.

virtual bool PVideoDevice::GetAttributes ( Attributes & attributes )

virtual

Get video attributes.

Reimplemented in PVideoInputDeviceIndirect.

virtual int PVideoDevice::GetChannel ( ) const

virtual

Get the video channel to be used on the device.

Default behaviour returns the value of the channelNumber variable.

Reimplemented in PVideoInputDeviceIndirect.

virtual PStringArray PVideoDevice::GetChannelNames ( )

virtual

Get the names of video channels available on the device.

Reimplemented in PVideoInputEmulatedDevice, and PVideoInputDeviceIndirect.

virtual PString PVideoDevice::GetColourFormat ( ) const

virtual

Get the colour format being used.

If a converter exists, the destination colour format of the converter is returned, not the underlying physical device. If you wish the physical device colout format use PVideoFrameInfo::GetColourFormat().

Reimplemented from PVideoFrameInfo.

virtual PString PVideoDevice::GetDeviceName ( ) const

inlinevirtual

Get the device name of the open device.

Reimplemented in PVideoInputDeviceIndirect.

References m_deviceName.

PString PVideoDevice::GetDeviceNameFromOpenArgs ( const OpenArgs & args ) const

protected

virtual PStringArray PVideoDevice::GetDeviceNames ( ) const

pure virtual

Get a list of all of the drivers available.

Implemented in PVideoInputDeviceIndirect, and P_WXWINDOWS_DEVICE_CLASS.

virtual PBoolean PVideoDevice::GetFrameSize	(	unsigned &	width,
		unsigned &	height
	)		const

virtual

Get the frame size being used.

If a converter exists, the destination frame size of the converter is returned, not the underlying physical device. If you wish the physical device frame size use PVideoFrameInfo::GetFrameSize().

Reimplemented from PVideoFrameInfo.

virtual PBoolean PVideoDevice::GetFrameSizeLimits	(	unsigned &	minWidth,
		unsigned &	minHeight,
		unsigned &	maxWidth,
		unsigned &	maxHeight
	)

virtual

Get the minimum & maximum size of a frame on the device.

Default behaviour returns the value 1 to UINT_MAX for both and returns false.

Parameters

minWidth	Variable to receive minimum width
minHeight	Variable to receive minimum height
maxWidth	Variable to receive maximum width
maxHeight	Variable to receive maximum height

Reimplemented in PVideoInputEmulatedDevice, PVideoInputDeviceIndirect, and PVideoInput1394DcDevice.

virtual int PVideoDevice::GetLastError ( ) const

inlinevirtual

Get the last error code.

This is a platform dependent number.

Reimplemented in PVideoInputDeviceIndirect.

References m_lastError.

virtual PINDEX PVideoDevice::GetMaxFrameBytes ( )

virtual

Get the maximum frame size in bytes.

This gets the maximum of the physical device or the converted frame size and colour format. It is guranteed to be enought memory space for any video grab or output.

Note, a particular device may be able to provide variable length frames (eg motion JPEG) so this will be the maximum size of all frames.

Reimplemented in PVideoOutputDeviceRGB, and PVideoInput1394DcDevice.

PINDEX PVideoDevice::GetMaxFrameBytesConverted ( PINDEX rawFrameBytes ) const

protected

virtual int PVideoDevice::GetNumChannels ( )

virtual

Get the number of video channels available on the device.

Default behaviour returns 1.

Reimplemented in PVideoInputEmulatedDevice, PVideoInputDeviceIndirect, and PVideoInput1394DcDevice.

virtual PString PVideoDevice::GetPreferredColourFormat ( )

inlinevirtual

Get preferred native colour format from video capture device.

Returns empty == no preference

References m_preferredColourFormat.

virtual PBoolean PVideoDevice::GetVFlipState ( )

virtual

Get the video conversion vertical flip state.

Default action is to return false.

virtual VideoFormat PVideoDevice::GetVideoFormat ( ) const

virtual

Get the video format being used.

Default behaviour returns the value of the videoFormat variable.

virtual PBoolean PVideoDevice::IsOpen ( )

pure virtual

Determine if the device is currently open.

Implemented in PVideoInputDeviceIndirect, P_WXWINDOWS_DEVICE_CLASS, and PVideoInput1394DcDevice.

virtual PBoolean PVideoDevice::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

Implemented in PVideoInputDeviceIndirect, PVideoInputDevice, P_WXWINDOWS_DEVICE_CLASS, and PVideoInput1394DcDevice.

virtual PBoolean PVideoDevice::OpenFull	(	const OpenArgs &	args,
		PBoolean	startImmediate = `true`
	)

virtual

Open the device given the device name.

Parameters

args	Parameters to set on opened device
startImmediate	Immediately start device

Reimplemented in PVideoInputDeviceIndirect.

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

int PVideoDevice::ParseDeviceNameTokenInt	(	const char *	token,
		int	defaultValue
	)

protected

Referenced by P_WXWINDOWS_DEVICE_CLASS::InternalOpen().

PString PVideoDevice::ParseDeviceNameTokenString	(	const char *	token,
		const char *	defaultValue
	)

protected

Referenced by P_WXWINDOWS_DEVICE_CLASS::InternalOpen().

uint64_t PVideoDevice::ParseDeviceNameTokenUnsigned	(	const char *	token,
		uint64_t	defaultValue
	)

protected

virtual void PVideoDevice::PrintOn ( ostream & strm ) const

virtual

Output the contents of the object to the stream.

The exact output is dependent on the exact semantics of the descendent class. This is primarily used by the standard operator<< function.

The default behaviour is to print the class name.

Reimplemented from PVideoFrameInfo.

Reimplemented in PVideoInputDeviceIndirect.

virtual bool PVideoDevice::SetAttributes ( const Attributes & attributes )

virtual

Set video attributes.

Reimplemented in PVideoInputDeviceIndirect.

virtual PBoolean PVideoDevice::SetChannel ( int channelNumber )

virtual

Set the video channel to be used on the device.

The channel number is an integer from 0 to GetNumChannels()-1. The special value of -1 will find the first working channel number.

Default behaviour sets the value of the channelNumber variable and then returns true.

Parameters

channelNumber New channel number for device.

Reimplemented in PVideoInputDeviceIndirect, and PVideoInput1394DcDevice.

virtual PBoolean PVideoDevice::SetColourFormatConverter ( const PString & colourFormat )

virtual

Set the colour format to be used, trying converters if available.

This function will set the colour format on the device to one that is compatible with a registered converter, and install that converter so that the correct format is used.

Reimplemented in PVideoInputDeviceIndirect, and PVideoInput1394DcDevice.

virtual bool PVideoDevice::SetFrameInfoConverter ( const PVideoFrameInfo & info )

virtual

Set the frame info to be used, trying converters if available.

This function will simply call SetColourFormatConverter(), SetFrameSizeConverter() and SetFrameRate().

Reimplemented in PVideoInputDeviceIndirect.