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RTP_Packet Class Reference

This class encapsulates all the necessary information to break down or build up an RTP data packet as well as operations to access all data items in the packet. More...

#include <RTP.h>

List of all members.

Public Member Functions

 RTP_Packet (char *buffer, int length)
 Constructor for incoming RTP packets.

 RTP_Packet (unsigned char padding, unsigned char marker, unsigned char payloadType, ACE_UINT32 sequenceNumber, ACE_UINT32 timeStamp, ACE_UINT32 syncSource, unsigned char contribSourcCount, ACE_UINT32 contribSourceList[], char *data, ACE_UINT16 dataSize)
 Constructor for outgoing RTP packets.

 ~RTP_Packet (void)
 Destructor.

ACE_UINT16 packet_size (void)
 Returns the size of the RTP packet in bytes.

ACE_UINT16 payload_size (void)
 Returns the size of the payload in bytes.

void get_frame_info (TAO_AV_frame_info *frame_info)
 Populates the passed in frame_info.

int is_valid (void)
 Returns 1 if packet is valid and 0 if not.

unsigned int ver (void)
 Returns the RTP version of the packet.

unsigned int pad (void)
 Returns 1 if the padding bit is set, 0 if not.

unsigned int ext (void)
 Returns 1 if the header extension bit is set, 0 if not.

unsigned int ext_bytes (void)
 Returns the number of bytes in the header extension or 0 if no extension.

unsigned int cc (void)
unsigned int mrk (void)
 Returns 1 if the marker bit is set, 0 if not.

unsigned int pt (void)
 Returns the payload type of the packet.

ACE_UINT16 sn (void)
 Returns the sequence number of the packet.

ACE_UINT32 ts (void)
 Returns the timestamp of the packet.

ACE_UINT32 ssrc (void)
 Returns the synchronization source id of the packet.

void get_csrc_list (ACE_UINT32 **csrc_list, ACE_UINT16 &length)
void get_payload (char **payload, ACE_UINT16 &size)
void get_packet_data (char **packet, ACE_UINT16 &size)

Private Attributes

char packet_ [RTP_MTU]
 Local buffer to hold the RTP packet.

ACE_UINT32 host_byte_order_csrc_list_ [15]
char host_byte_order_payload_ [RTP_MTU]
 Local buffer to hold the payload with the values stored in host byte order.

unsigned int extension_bytes_
 The number of bytes in the header extension - 0 if no extension.

ACE_UINT16 packet_size_
 The size of the overall data packet.

ACE_UINT16 payload_size_
 The size of the payload portion of the packet.

Detailed Description

This class encapsulates all the necessary information to break down or build up an RTP data packet as well as operations to access all data items in the packet.

Definition at line 294 of file RTP.h.

Constructor & Destructor Documentation

TAO_BEGIN_VERSIONED_NAMESPACE_DECL RTP_Packet::RTP_Packet (  char *  buffer,
int  length
) 
 

Constructor for incoming RTP packets.

Definition at line 49 of file RTP.cpp.

References cc(), ext(), extension_bytes_, host_byte_order_csrc_list_, host_byte_order_payload_, ACE_OS::memcpy(), packet_, pt(), RTP_PT_L16_MONO, RTP_PT_L16_OTHER, and RTP_PT_L16_STEREO. 

00050 {
00051   // skip the standard header info
00052   int index = 12;
00053 
00054   ACE_OS::memcpy(this->packet_, buffer, length);
00055 
00056   for (int j=0; j<(int)this->cc(); j++)
00057     {
00058       this->host_byte_order_csrc_list_[j] = ntohl(*(ACE_UINT32*)&buffer[index]);
00059       index+=4;
00060     }
00061 
00062   // ignore the header extension if there is one
00063   if (this->ext())
00064     {
00065       index+=2;
00066       int extension_data_size = ntohs(*(ACE_UINT16*)&buffer[index]);
00067       index+=2;
00068       index+=extension_data_size;
00069 
00070       this->extension_bytes_ = 4 + extension_data_size;
00071     }
00072   else
00073     this->extension_bytes_ = 0;
00074 
00075   this->packet_size_ = static_cast<ACE_UINT16> (length);
00076   this->payload_size_ = static_cast<ACE_UINT16> (length-index);
00077 
00078   // This is necessary only for payload types that have 16 bit values to correct
00079   //  the network byte ordering.
00080   if ((this->pt() == RTP_PT_L16_OTHER) ||
00081       (this->pt() == RTP_PT_L16_STEREO) ||
00082       (this->pt() == RTP_PT_L16_MONO))
00083     {
00084       for (int i=0; i < payload_size_; i+=2)
00085         {
00086           *(ACE_UINT16*)&this->host_byte_order_payload_[i] = ntohs(*(ACE_UINT16*)&this->packet_[index]);
00087           index+=2;
00088         }
00089     }
00090   else
00091     for (int i=0; i<this->payload_size_; i++)
00092       {
00093         this->host_byte_order_payload_[i] = this->packet_[index];
00094         index++;
00095       }
00096 }

RTP_Packet::RTP_Packet (  unsigned char  padding,
unsigned char  marker,
unsigned char  payloadType,
ACE_UINT32  sequenceNumber,
ACE_UINT32  timeStamp,
ACE_UINT32  syncSource,
unsigned char  contribSourcCount,
ACE_UINT32  contribSourceList[],
char *  data,
ACE_UINT16  dataSize
) 
 

Constructor for outgoing RTP packets.

RTP_Packet::~RTP_Packet (  void   ) 
 

Destructor.

Definition at line 178 of file RTP.cpp. 

00179 {
00180 }

Member Function Documentation

unsigned int RTP_Packet::cc (  void   ) 
 

Returns the contributing source count. This should only be non-zero for mixers.

Definition at line 213 of file RTP.cpp.

References packet_.

Referenced by get_csrc_list(), is_valid(), and RTP_Packet(). 

00214 {
00215   return ( this->packet_[0] & 0x0F ) ;
00216 }

unsigned int RTP_Packet::ext (  void   ) 
 

Returns 1 if the header extension bit is set, 0 if not.

Definition at line 207 of file RTP.cpp.

References packet_.

Referenced by RTP_Packet(). 

00208 {
00209   return ( this->packet_[0] & 0x10 ) >> 4;
00210 }

unsigned int RTP_Packet::ext_bytes (  void   ) 
 

Returns the number of bytes in the header extension or 0 if no extension.

Definition at line 249 of file RTP.cpp.

References extension_bytes_. 

00250 {
00251   return this->extension_bytes_;
00252 }

void RTP_Packet::get_csrc_list (  ACE_UINT32 **  csrc_list,
ACE_UINT16 &  length
) 
 

Returns a pointer to the local contributing source list and its length. This should be empty except for mixers. RTP_Packet retains ownership.

Definition at line 294 of file RTP.cpp.

References cc(), and host_byte_order_csrc_list_. 

00295 {
00296   *csrc_list = this->host_byte_order_csrc_list_;
00297   length = static_cast<ACE_UINT16> (this->cc ());
00298 }

void RTP_Packet::get_frame_info (  TAO_AV_frame_info *  frame_info  ) 
 

Populates the passed in frame_info.

Definition at line 255 of file RTP.cpp.

References TAO_AV_frame_info::format, mrk(), pt(), TAO_AV_frame_info::sequence_num, sn(), ssrc(), TAO_AV_frame_info::ssrc, TAO_AV_frame_info::timestamp, and ts().

Referenced by TAO_AV_RTP_Object::handle_input(). 

00256 {
00257   frame_info->timestamp = this->mrk();
00258   frame_info->timestamp = this->ts();
00259   frame_info->ssrc = this->ssrc();
00260   frame_info->sequence_num = this->sn();
00261   frame_info->format = static_cast<CORBA::Octet> (this->pt());
00262 }

void RTP_Packet::get_packet_data (  char **  packet,
ACE_UINT16 &  size
) 
 

Returns a pointer to the locally stored rtp packet and its size in bytes. RTP_Packet retains ownership.

Definition at line 308 of file RTP.cpp.

References packet_.

Referenced by TAO_AV_RTP_Object::send_frame(). 

00309 {
00310   *packet = this->packet_;
00311   length = this->packet_size_;
00312 }

void RTP_Packet::get_payload (  char **  payload,
ACE_UINT16 &  size
) 
 

Returns a pointer to the locally stored payload and its size in bytes. The payload is returned in host byte order. RTP_Packet retains ownership.

Definition at line 301 of file RTP.cpp.

References host_byte_order_payload_.

Referenced by TAO_AV_RTP_Object::handle_input(). 

00302 {
00303   *payload = this->host_byte_order_payload_ ;
00304   length = this->payload_size_;
00305 }

int RTP_Packet::is_valid (  void   ) 
 

Returns 1 if packet is valid and 0 if not.

Definition at line 265 of file RTP.cpp.

References cc(), extension_bytes_, packet_, pad(), pt(), RTCP_PT_RR, RTCP_PT_SR, RTP_VERSION, and ver().

Referenced by RTCP_Channel_In::recv_rtp_packet(). 

00266 {
00267   // taken from RFC 1889 - Appendix A.1
00268 
00269   // make sure the RTP version is correct
00270   if (this->ver() != RTP_VERSION)
00271     return 0;
00272 
00273   // make sure the payload type is not SR or RR
00274   if ((this->pt() == RTCP_PT_SR) || (this->pt() == RTCP_PT_RR))
00275     return 0;
00276 
00277   // if the p bit is set, the last octet of the packet must contain a valid
00278   // octet count, in particular, less than the total packet length minus
00279   // the header size.
00280   if (this->pad() != 0)
00281     if ((unsigned int)this->packet_[this->packet_size_] >=
00282         (this->packet_size_ - (12 + this->cc() + this->extension_bytes_)))
00283       return 0;
00284 
00285   // If there is an extension, it is ignored (taken care of in constructor)
00286 
00287   // The length of the packet must be consistent with CC and payload type (if
00288   // payloads have a known length)
00289 
00290   return 1;
00291 }

unsigned int RTP_Packet::mrk (  void   ) 
 

Returns 1 if the marker bit is set, 0 if not.

Definition at line 219 of file RTP.cpp.

References packet_.

Referenced by get_frame_info(). 

00220 {
00221   return ( this->packet_[1] & 0x80 ) >> 7;
00222 }

ACE_UINT16 RTP_Packet::packet_size (  void   ) 
 

Returns the size of the RTP packet in bytes.

Definition at line 183 of file RTP.cpp. 

00184 {
00185     return this->packet_size_;
00186 }

unsigned int RTP_Packet::pad (  void   ) 
 

Returns 1 if the padding bit is set, 0 if not.

Definition at line 201 of file RTP.cpp.

References packet_.

Referenced by is_valid(). 

00202 {
00203   return ( this->packet_[0] & 0x20 ) >> 5;
00204 }

ACE_UINT16 RTP_Packet::payload_size (  void   ) 
 

Returns the size of the payload in bytes.

Definition at line 189 of file RTP.cpp.

Referenced by RTCP_Channel_Out::updateStatistics(). 

00190 {
00191     return this->payload_size_;
00192 }

unsigned int RTP_Packet::pt (  void   ) 
 

Returns the payload type of the packet.

Definition at line 225 of file RTP.cpp.

References packet_.

Referenced by get_frame_info(), is_valid(), RTP_Packet(), and RTCP_Channel_In::updateStatistics(). 

00226 {
00227   return ( this->packet_[1] & 0x7F ) ;
00228 }

ACE_UINT16 RTP_Packet::sn (  void   ) 
 

Returns the sequence number of the packet.

Definition at line 231 of file RTP.cpp.

Referenced by get_frame_info(), RTCP_Channel_Out::updateStatistics(), and RTCP_Channel_In::updateStatistics(). 

00232 {
00233   return ntohs(*(ACE_UINT16*)(&this->packet_[2])) ;
00234 }

ACE_UINT32 RTP_Packet::ssrc (  void   ) 
 

Returns the synchronization source id of the packet.

Definition at line 243 of file RTP.cpp.

Referenced by get_frame_info(), and TAO_AV_RTCP_Callback::receive_frame(). 

00244 {
00245   return ntohl(*(ACE_UINT32*)(&this->packet_[8])) ;
00246 }

ACE_UINT32 RTP_Packet::ts (  void   ) 
 

Returns the timestamp of the packet.

Definition at line 237 of file RTP.cpp.

Referenced by get_frame_info(), RTCP_Channel_Out::updateStatistics(), and RTCP_Channel_In::updateStatistics(). 

00238 {
00239   return ntohl(*(ACE_UINT32*)(&this->packet_[4])) ;
00240 }

unsigned int RTP_Packet::ver (  void   ) 
 

Returns the RTP version of the packet.

Definition at line 195 of file RTP.cpp.

References packet_.

Referenced by is_valid(). 

00196 {
00197   return ( this->packet_[0] & 0xC0 ) >> 6;
00198 }

Member Data Documentation

unsigned int RTP_Packet::extension_bytes_ [private]
 

The number of bytes in the header extension - 0 if no extension.

Definition at line 385 of file RTP.h.

Referenced by ext_bytes(), is_valid(), and RTP_Packet().

ACE_UINT32 RTP_Packet::host_byte_order_csrc_list_[15] [private]
 

Local buffer to hold the contributing source list with the values stored in host byte order.

Definition at line 379 of file RTP.h.

Referenced by get_csrc_list(), and RTP_Packet().

char RTP_Packet::host_byte_order_payload_[RTP_MTU] [private]
 

Local buffer to hold the payload with the values stored in host byte order.

Definition at line 382 of file RTP.h.

Referenced by get_payload(), and RTP_Packet().

char RTP_Packet::packet_[RTP_MTU] [private]
 

Local buffer to hold the RTP packet.

Definition at line 375 of file RTP.h.

Referenced by cc(), ext(), get_packet_data(), is_valid(), mrk(), pad(), pt(), RTP_Packet(), and ver().

ACE_UINT16 RTP_Packet::packet_size_ [private]
 

The size of the overall data packet.

Definition at line 388 of file RTP.h.

ACE_UINT16 RTP_Packet::payload_size_ [private]
 

The size of the payload portion of the packet.

Definition at line 391 of file RTP.h.

The documentation for this class was generated from the following files:
Generated on Sun Jan 27 16:06:29 2008 for TAO_AV by doxygen 1.3.6