#include <h323caps.h>

Inheritance diagram for H323Capability:

Collaboration diagram for H323Capability:

Public Member Functions
Construction
	H323Capability ()

	H323Capability (const H323Capability &other)

H323Capability &	operator= (const H323Capability &other)

	~H323Capability ()

Overrides from class PObject
Comparison	Compare (const PObject &obj) const

void	PrintOn (ostream &strm) const

Protected Member Functions
OpalMediaFormat &	GetWritableMediaFormat () const

Protected Attributes
unsigned	assignedCapabilityNumber

CapabilityDirection	capabilityDirection
	Unique ID assigned to capability. More...

OpalMediaFormat	m_mediaFormat

Friends
class	H323Capabilities

Identification functions
enum	MainTypes { e_Audio, e_Video, e_Data, e_UserInput, e_GenericControl, e_H235Security, e_FEC, e_NumMainTypes }

virtual MainTypes	GetMainType () const =0

virtual unsigned	GetSubType () const =0

virtual PString	GetFormatName () const =0

Operations
enum	{ DefaultAudioSessionID = 1, DefaultVideoSessionID = 2, DefaultDataSessionID = 3, MasterAllocatedBaseSessionID, DeferredSessionID = 1000000 }

virtual unsigned	GetDefaultSessionID () const

virtual void	SetTxFramesInPacket (unsigned frames)

virtual unsigned	GetTxFramesInPacket () const

virtual unsigned	GetRxFramesInPacket () const

virtual H323Channel *	CreateChannel (H323Connection &connection, H323Channel::Directions dir, unsigned sessionID, const H245_H2250LogicalChannelParameters *param) const

static H323Capability *	Create (const PString &name)

Protocol manipulation
enum	CommandType { e_TCS, e_OLC, e_ReqMode }

virtual PBoolean	OnSendingPDU (H245_Capability &pdu) const =0

virtual PBoolean	OnSendingPDU (H245_DataType &pdu) const

virtual PBoolean	OnSendingPDU (H245_ModeElement &pdu) const

virtual PBoolean	OnReceivedPDU (const H245_Capability &pdu)

virtual PBoolean	OnReceivedPDU (const H245_DataType &pdu, PBoolean receiver)

virtual PBoolean	IsMatch (const PASN_Object &subTypePDU, const PString &mediaPacketization) const

virtual PBoolean	IsUsable (const H323Connection &connection) const

Member variable access
enum	CapabilityDirection { e_Unknown, e_Receive, e_Transmit, e_ReceiveAndTransmit, e_NoDirection, NumCapabilityDirections }

CapabilityDirection	GetCapabilityDirection () const

void	SetCapabilityDirection (CapabilityDirection dir)

unsigned	GetCapabilityNumber () const
	Get unique capability number. More...

void	SetCapabilityNumber (unsigned num)
	Set unique capability number. More...

OpalMediaFormat	GetMediaFormat () const

bool	UpdateMediaFormat (const OpalMediaFormat &format)

RTP_DataFrame::PayloadTypes	GetPayloadType () const
	Get the payload type for the capaibility. More...

void	SetPayloadType (RTP_DataFrame::PayloadTypes pt)
	Set the payload type for the capaibility. More...

Detailed Description

This class describes the interface to a capability of the endpoint, usually a codec, used to transfer data via the logical channels opened and managed by the H323 control channel.

Note that this is not an instance of the codec itself. Merely the description of that codec. There is typically only one instance of this class contained in the capability tables of the endpoint. There may be several instances of the actualy codec managing the conversion of an individual stream of data.

An application may create a descendent off this class and override functions as required for describing a codec that it implements.

Member Enumeration Documentation

anonymous enum

Enumerator
DefaultAudioSessionID
DefaultVideoSessionID
DefaultDataSessionID
MasterAllocatedBaseSessionID
DeferredSessionID

enum H323Capability::CapabilityDirection

Enumerator
e_Unknown
e_Receive	Receive capability.
e_Transmit	Transmit only capability.
e_ReceiveAndTransmit	Symmetric capability.
e_NoDirection	Ca;ability type has no direction.
NumCapabilityDirections

enum H323Capability::CommandType

Enumerator
e_TCS
e_OLC
e_ReqMode

enum H323Capability::MainTypes

Enumerator
e_Audio	Audio codec capability.
e_Video	Video codec capability.
e_Data	Arbitrary data capability.
e_UserInput	User Input capability.
e_GenericControl	Generic Control.
e_H235Security	H.235 security capability.
e_FEC	Forward Error Correction.
e_NumMainTypes	Count of main types.

Constructor & Destructor Documentation

H323Capability::H323Capability ( )

Create a new capability specification.

H323Capability::H323Capability ( const H323Capability & other )

H323Capability::~H323Capability ( )

Destroy capability.

Member Function Documentation

Comparison H323Capability::Compare ( const PObject & obj ) const

Compare two capability instances. This compares the main and sub-types of the capability.

static H323Capability* H323Capability::Create ( const PString & name )

static

Create an H323Capability descendant given a string name. This uses the registration system to create the capability.

Parameters

name	Name of capability

virtual H323Channel* H323Capability::CreateChannel	(	H323Connection &	connection,
		H323Channel::Directions	dir,
		unsigned	sessionID,
		const H245_H2250LogicalChannelParameters *	param
	)		const

virtual

Create the channel instance, allocating resources as required. This creates a logical channel object appropriate for the parameters provided. Not if param is NULL, sessionID must be provided, otherwise this is taken from the fields in param.

Parameters

connection	Owner connection for channel
dir	Direction of channel
sessionID	Session ID for RTP channel
param	Parameters for channel

Reimplemented in H323RealTimeCapability, and H323_T120Capability.

CapabilityDirection H323Capability::GetCapabilityDirection ( ) const

inline

Get the direction for this capability.

References capabilityDirection.

unsigned H323Capability::GetCapabilityNumber ( ) const

inline

Get unique capability number.

References assignedCapabilityNumber.

virtual unsigned H323Capability::GetDefaultSessionID ( ) const

virtual

Get the default RTP session. This function gets the default RTP session ID for the capability type. For example audio capabilities return the value H323Capability::DefaultAudioSessionID etc.

The default behaviour returns zero, indicating it is not an RTP based capability.

Reimplemented in H323DataCapability, H323VideoCapability, and H323AudioCapability.

virtual PString H323Capability::GetFormatName ( ) const

pure virtual

Get the name of the media data format this class represents.

Implemented in H323_UserInputCapability, H323_G711Capability, H323H239ControlCapability, H323H239VideoCapability, H323GenericVideoCapabilityTemplate< oid, fmtFunc >, H323GenericAudioCapabilityTemplate< oid, fmtFunc, fixedBitRate >, H323H263Capability, H323H261Capability, H323CodecPluginGenericVideoCapability, H323CodecPluginNonStandardVideoCapability, H323CodecPluginGenericAudioCapability, H323CodecPluginNonStandardAudioCapability, H323AudioPluginCapability, H323_H224_HDLCTunnelingCapability, H323_T120Capability, and H323_H224_AnnexQCapability.

virtual MainTypes H323Capability::GetMainType ( ) const

pure virtual

Get the main type of the capability.

This function is overridden by one of the three main sub-classes off which real capabilities would be descendend.

Implemented in H323_UserInputCapability, H323DataCapability, H323GenericControlCapability, H323VideoCapability, and H323AudioCapability.

OpalMediaFormat H323Capability::GetMediaFormat ( ) const

Get media format of the media data this class represents.

Referenced by GetPayloadType().

RTP_DataFrame::PayloadTypes H323Capability::GetPayloadType ( ) const

inline

Get the payload type for the capaibility.

References GetMediaFormat(), and OpalMediaFormat::GetPayloadType().

virtual unsigned H323Capability::GetRxFramesInPacket ( ) const

virtual

Get the maximum size (in frames) of data that can be received in a single PDU.

The default behaviour returns the value 1.

Reimplemented in H323AudioCapability.

virtual unsigned H323Capability::GetSubType ( ) const

pure virtual

Get the sub-type of the capability. This is a code dependent on the main type of the capability.

Implemented in H323_UserInputCapability, H323_G711Capability, H323GenericDataCapability, H323NonStandardDataCapability, H323GenericControlCapability, H323ExtendedVideoCapability, H323GenericVideoCapability, H323NonStandardVideoCapability, H323GenericAudioCapability, H323NonStandardAudioCapability, H323H263Capability, H323H261Capability, H323AudioPluginCapability, H323_H224_HDLCTunnelingCapability, and H323_T120Capability.

virtual unsigned H323Capability::GetTxFramesInPacket ( ) const

virtual

Get the maximum size (in frames) of data that will be transmitted in a single PDU.

The default behaviour returns the value 1.

Reimplemented in H323AudioCapability.

OpalMediaFormat& H323Capability::GetWritableMediaFormat ( ) const

protected

Referenced by SetPayloadType().

virtual PBoolean H323Capability::IsMatch	(	const PASN_Object &	subTypePDU,
		const PString &	mediaPacketization
	)		const

virtual

Compare the PDU part of the capability.

Parameters

subTypePDU	sub-type PDU of H323Capability
mediaPacketization	Media packetization used

Reimplemented in H323GenericDataCapability, H323NonStandardDataCapability, H323GenericControlCapability, H323ExtendedVideoCapability, H323GenericVideoCapability, H323NonStandardVideoCapability, H323GenericAudioCapability, H323NonStandardAudioCapability, and H323H263Capability.

virtual PBoolean H323Capability::IsUsable ( const H323Connection & connection ) const

virtual

Validate that the capability is usable given the connection. This checks agains the negotiated protocol version number and remote application to determine if this capability should be used in TCS or OLC pdus.

The default behaviour returns true.

Reimplemented in H323_UserInputCapability.

virtual PBoolean H323Capability::OnReceivedPDU ( const H245_Capability & pdu )

virtual

This function is called whenever and incoming TerminalCapabilitySet PDU is received on the control channel, and a new H323Capability descendent was created. This completes reading fields from the PDU into the classes members.

If the function returns false then the received PDU codec description is not supported, so will be ignored.

The default behaviour sets the capabilityDirection member variable from the PDU and then returns true. Note that this means it is very important to call the ancestor function when overriding.

Parameters

pdu	PDU to get information from

Reimplemented in H323_UserInputCapability, H323DataCapability, H323GenericControlCapability, H323VideoCapability, and H323AudioCapability.

virtual PBoolean H323Capability::OnReceivedPDU	(	const H245_DataType &	pdu,
		PBoolean	receiver
	)

virtual

This function is called whenever and incoming OpenLogicalChannel PDU has been used to construct the control channel. It allows the capability to set from the PDU fields, information in members specific to the class.

The default behaviour is pure.

Parameters

pdu	PDU to get information from
receiver	Is receiver OLC

Reimplemented in H323_UserInputCapability, H323DataCapability, H323VideoCapability, and H323AudioCapability.

virtual PBoolean H323Capability::OnSendingPDU ( H245_Capability & pdu ) const

pure virtual

This function is called whenever and outgoing TerminalCapabilitySet PDU is being constructed for the control channel. It allows the capability to set the PDU fields from information in members specific to the class.

The default behaviour is pure.

Parameters

pdu	PDU to set information on

Implemented in H323_UserInputCapability, H323DataCapability, H323GenericControlCapability, H323VideoCapability, and H323AudioCapability.

virtual PBoolean H323Capability::OnSendingPDU ( H245_DataType & pdu ) const

virtual

This function is called whenever and outgoing OpenLogicalChannel PDU is being constructed for the control channel. It allows the capability to set the PDU fields from information in members specific to the class.

The default behaviour is pure.

Parameters

pdu	PDU to set information on

Reimplemented in H323_UserInputCapability, H323DataCapability, H323VideoCapability, and H323AudioCapability.

virtual PBoolean H323Capability::OnSendingPDU ( H245_ModeElement & pdu ) const

virtual

This function is called whenever and outgoing RequestMode PDU is being constructed for the control channel. It allows the capability to set the PDU fields from information in members specific to the class.

The default behaviour is pure.

Parameters