SH::RTPDecoderSH Class Reference
[StreamHandlers]

#include <MNRTPDecoderSH.h>

Inheritance diagram for SH::RTPDecoderSH:

[legend]Collaboration diagram for SH::RTPDecoderSH:

[legend]List of all members.

Public Member Functions
void	set_payload_types (const SDP::PayloadTypeTable *ptt_ptr)
SH_RC	push_decode (DataPtr item)
SH_RC	pull_decode (DataPtr &item)
DataPtr	evalLCRTPPacket (MNRTPPacketPtr packet, MNRope *&payload, u_int64_t &bytecount)
void	tfrc_packet_received (MNRope *&payload, MNRTPPacketPtr packet)
void	send_feedback (u_int32 ssrc, LCfeedb_tfrc_t *reply)
DataPtr	evalRTPPacket (MNRTPPacketPtr packet, MNRope *&payload, u_int64_t &bytecount)
void	evalSyncTimestamp (unsigned rtpTimestamp, struct timeval &resPT)
void	evalSyncRTCP (u_int32 ntp_upper, u_int32 ntp_lower, u_int32 rtpTimestamp)
void	resetSyncTime ()
	RTPDecoderSH (SHGraphManager *mgr, u_int32_t runtimeId, MNSelector &sel)
virtual	~RTPDecoderSH ()
virtual SH_RC	initSH ()
virtual SH_RC	uninitSH ()
virtual SH_RC	startStreaming ()
virtual SH_RC	stopStreaming ()
virtual SinkEndpoint **	getSinkSpecs ()
virtual SourceEndpoint **	getSourceSpecs ()
virtual bool	isConnected () const
Protected Member Functions
virtual void	pushReport (ReportPtr report, Base::Direction d)
Protected Attributes
SinkEndpoint *	_in_ep_a [1]
SourceEndpoint *	_out_ep_a [1]
RTPDecoderSinkEndpoint	_inEP
RTPDecoderSourceEndpoint	_outEP

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Detailed Description

The class implements a stream handler that decodes RTP packets. It operates as a through stream handler, although has several timers.

It takes the configuration attributes

• SH_ATTR_HAS_ORDERED_DATA: A boolean value that determines whether this stream handler works in LC mode or not. This attribute will probably be replaced by an attribute that allows to choose among several retransmission schemes in the future.
• SH_ATTR_RTP_PAYLOAD_TYPES: A pointer to a table of payload types that are partly predefined and will partly be inserted dynamically. The concept is not cleanly integrated yet. It will have to be revised when a separate media (or SDP) module is created apart from RTP and RTSP modules.
• SH_ATTR_LCRTP_REPEAT_TIMES: An integer that defines the number of times that this stream handler should request retransmissions of the packets that are in its loss list. After this number of loops it gives up even if packets are still missing.
• SH_ATTR_IGNORE_SYNC_TIMESTAMP: A bool flag indicating if the experimental synchronization calculation should be ignored (if set to true) or not. If the calculation is not done, you will not be able to show MP4 on mplayer, since this one relies on it. If you wish to use the calculation, you should use the SHRTPData member functions to access data. Note this is experimental and subject to change in future!

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Constructor & Destructor Documentation

SH::RTPDecoderSH::RTPDecoderSH (  SHGraphManager *  mgr, u_int32_t  runtimeId, MNSelector &  sel )

virtual SH::RTPDecoderSH::~RTPDecoderSH (   )  [virtual]

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Member Function Documentation

DataPtr SH::RTPDecoderSH::evalLCRTPPacket (  MNRTPPacketPtr  packet, MNRope *&  payload, u_int64_t &  bytecount )

In the non-LC case, packet processing needs on calling of the decoding functions. In the LC case, this function is called because lists need to be updated and the bytecount must be maintained. When this function is called, the packet will not contain the payload any more. The reason is that this function is called in a loop until all payload is consumed by the decoder, but extracting from the packet is possible only once. Parameters: packet  The arriving packet without its payload. payload  INOUT variable. The payload that has been extracted from the packet. The function can be called repeatedly until this pointer is NULL or payload->size() is 0. bytecount  OUT variable. The bytecount for this extracted part of the payload, if successfully returned. Returns: Either DataPtr.isNull() or it referes to one decoded block of payload that has also been removed from the payload rope.

DataPtr SH::RTPDecoderSH::evalRTPPacket (  MNRTPPacketPtr  packet, MNRope *&  payload, u_int64_t &  bytecount )

This function is similar to evalLCRTPPacket, with the difference that a different data structure SHRTPData is set up containing timing and synchronization information together with the decoded block of payload. The function will also collect fragments by saving decoded data in a member rope until the payload decoder tells a frame has been completed. Decoding is done by calling evalLCRTPPacket so hopefully none of LCretrans stuff will be broken. See also: evalLCRTPPacket Returns: DataPtr.isNull() if a frame has not been completed yet or a pointer to an SHRTPData containing relevant RTP information together with one decoded data frame/sample.

void SH::RTPDecoderSH::evalSyncRTCP (  u_int32  ntp_upper, u_int32  ntp_lower, u_int32  rtpTimestamp )

This function evaluates the NTP timestamp contained in the RTCP packet in relation to the RTP timestamp (also in RTCP). Doing so, a wallclock time for presentation can be derived. Parameters: ntp_upper  MSW of NTP timestamp ntp_lower  LSW of NTP timestamp rtpTimestamp  RTP timestamp

void SH::RTPDecoderSH::evalSyncTimestamp (  unsigned  rtpTimestamp, struct timeval &  resPT )

This function calculates the presentation time of a frame from RTP and, if available, RTCP timestamps. Parameters: rtpTimestamp  timestamp of RTP header resPT  OUT variable containing the calculated presentation time as of type struct timeval

virtual SinkEndpoint** SH::RTPDecoderSH::getSinkSpecs (   )  [virtual]

Provide a list of valid sink endpoint specifications to the graph manager. getSinkPorts() is called by the graph manager and returns an array of pointers to EndpointSpec structures, or NULL if no endpoints in this direction are supported. It is typical that the length of such an array is 1, because several alternatives are specified by one EndpointSpec object, and the maximum number of identical Endpoints is a parameter of the EndpointSpec as well. The maximum number of endpoints may be dynamic, e.g. in an RTP source SH, new SSRCs or PTs will result in the provision of a new Endpoint. The array of endpoint specs is not NULL terminated, it is expected that the application knows the number of endpoints from numSinkSpecs(). Returns: An array of endpoint specification. Implements SH::Status.

virtual SourceEndpoint** SH::RTPDecoderSH::getSourceSpecs (   )  [virtual]

Provide a list of valid source endpoint specifications to the graph manager. getSourceSpecs() works like getSinkSpecs() but on the source endpoint specifications. Returns: An array of endpoint specification. Implements SH::Status.

virtual SH_RC SH::RTPDecoderSH::initSH (   )  [virtual]

See also: SH Reimplemented from SH::Base.

virtual bool SH::RTPDecoderSH::isConnected (   )  const [virtual]

Indicate whether a sufficient number of endpoints are connected for the stream handler to be active. True if a sufficient number of endpoints is connected for the stream handler to operate in a graph. This should always be true when the stream handler is part of an active graph. This can be called on all stream handlers of a graph to determine whether it will activate successfully. Implements SH::Status.

SH_RC SH::RTPDecoderSH::pull_decode (  DataPtr &  item  )

SH_RC SH::RTPDecoderSH::push_decode (  DataPtr  item  )

virtual void SH::RTPDecoderSH::pushReport (  ReportPtr  report, Base::Direction  d )  [protected, virtual]

void SH::RTPDecoderSH::resetSyncTime (   )  [inline]

reset the presentation timestamp Darwin server (maybe others?) rearranges RTP timestamps after seeking

void SH::RTPDecoderSH::send_feedback (  u_int32  ssrc, LCfeedb_tfrc_t *  reply )

void SH::RTPDecoderSH::set_payload_types (  const SDP::PayloadTypeTable *  ptt_ptr  )

Some decoders, above all of dynamic payload types, need information given in the payload type table. Thus, this table must be set here to be instantiated with the decoder factory. Parameters: ptt_ptr  Pointer to the corresponding payload type table.

virtual SH_RC SH::RTPDecoderSH::startStreaming (   )  [virtual]

See also: SH Reimplemented from SH::Base.

virtual SH_RC SH::RTPDecoderSH::stopStreaming (   )  [virtual]

See also: SH Reimplemented from SH::Base.

void SH::RTPDecoderSH::tfrc_packet_received (  MNRope *&  payload, MNRTPPacketPtr  packet )

virtual SH_RC SH::RTPDecoderSH::uninitSH (   )  [virtual]

See also: SH Reimplemented from SH::Base.

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Member Data Documentation

SinkEndpoint* SH::RTPDecoderSH::_in_ep_a[1] [protected]

RTPDecoderSinkEndpoint SH::RTPDecoderSH::_inEP [protected]

SourceEndpoint* SH::RTPDecoderSH::_out_ep_a[1] [protected]

RTPDecoderSourceEndpoint SH::RTPDecoderSH::_outEP [protected]

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

• MNRTPDecoderSH.h

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