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12 Feb 2007

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SDP Class Reference

<class description="" goes="" here=""> RTSP helper class for SDP generation needed as response to an RTSP DESCRIBE More...

#include <SDP.hpp>

List of all members.

Public Member Functions
	SDP ()
	Default constructor.
	~SDP ()
	Destructor.
bool	parse (const char *sdp)
	Parse an SDP description.
const struct session *	firstSession () const
	Return the fields of the first session of this SDP description instance.
Static Public Member Functions
char *	generate (ContainerInfo *stream, bool perfectHit, const char *filename, const char *localAddr, int SL_PAYLOAD_TYPE, int sizeLength, int dtsDeltaLength, const TerminalCapabilities *tc=NULL, bool includeRtxInfo=false, std::list< rtx_group * > *groups=NULL)
	generates a (S)ession (D)escription (P)rotocol string for the given ContainerInfo object.
void	encodeDecoderConfig (u8 *dest, const u8 *source, u32 n)
	encodes the source-decoder config into dest, which must be of size 2n+1
void	decodeDecoderConfig (u8 *dest, const u8 *source, u32 srcSize)
	decodes the encoded-decoderConfig stored in source into dest which must be of size srcSize/2

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Detailed Description

<class description="" goes="" here=""> RTSP helper class for SDP generation needed as response to an RTSP DESCRIBE

Author:

Peter Schojer

Version:

Id

SDP.hpp,v 1.5 2006/01/20 15:37:54 mkropfbe Exp

Definition at line 67 of file SDP.hpp.

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Member Function Documentation

const struct SDP::session * SDP::firstSession (   )  const

Return the fields of the first session of this SDP description instance. Returns: a pointer to the struct of the first session, or NULL if there are no sessions. See also: parse(const char *) Definition at line 166 of file SDP.cpp. { return sessionList.empty() ? NULL : sessionList.front(); }

char * SDP::generate (  ContainerInfo *  stream, bool  perfectHit, const char *  filename, const char *  localAddr, int  SL_PAYLOAD_TYPE, int  sizeLength, int  dtsDeltaLength, const TerminalCapabilities *  tc = NULL, bool  includeRtxInfo = false, std::list< rtx_group * > *  groups = NULL )  [static]

generates a (S)ession (D)escription (P)rotocol string for the given ContainerInfo object. Will succeed on objects without any elementary streams! Definition at line 171 of file SDP.cpp. References encodeDecoderConfig(), TerminalCapabilities::getDisplayHeight(), TerminalCapabilities::getDisplayWidth(), ContainerInfo::getESList(), ContainerInfo::getIODHandle(), TerminalCapabilities::getMaxDecoderBitRateInBit(), TerminalCapabilities::getNetworkCapacityInByte(), TerminalCapabilities::getNumAudioChannels(), and ContainerInfo::getRtxGroup(). { // mslc.SizeLength + mslc.DTSDeltaLength replaced by // sizeLength + dtsDeltaLength assert(stream!=NULL); char *buffer = new char[MSG_BUFFER_SIZE]; buffer[0] = 0; char *next = buffer; int cnt = 0; //disable rtx when rtxconfig is missing if(groups==NULL) includeRtxInfo = false; #if defined WIN32 && !(defined WINCE) struct timeb tv; ftime(&tv); cnt = sprintf(next, "v=0\r\no=%s %i %i IN IP4 %s\r\ns=%s\r\nu=http:///\r\ne=admin@\r\n",SERVER_ID, (int) tv.time, (int) tv.millitm, localAddr, filename); #else timeval tv; gettimeofday(&tv, 0); cnt = sprintf(next, "v=0\r\no=%s %i %i IN IP4 %s\r\ns=%s\r\nu=http:///\r\ne=admin@\r\n",SERVER_ID, (int) tv.tv_sec, (int) tv.tv_usec, localAddr, filename); #endif next += cnt; list <ESInfo*> * es = stream->getESList(); list < ESInfo * >::const_iterator li = es->begin(); float duration = 0; u32 bitRateInKilobits = 0; while (li != es->end()) { if (duration < ((float) (*li)->getDurationInMs() / 1000.0)) { duration = ((float) (*li)->getDurationInMs() / 1000.0); } if ((*li)->isAudioStream() || (*li)->isVisualStream()) { bitRateInKilobits += ((*li)->getAvgBandwidth() / 1024); } ++li; } if(tc) { u32 bw = tc->getNetworkCapacityInByte()*8; if(bw==0) bw = tc->getMaxDecoderBitRateInBit(); else if(tc->getMaxDecoderBitRateInBit() && tc->getMaxDecoderBitRateInBit() < bw) { bw = tc->getMaxDecoderBitRateInBit(); } if((bw/1024)<bitRateInKilobits) bitRateInKilobits=bw; } /* Connection Data c=<network type> <address type> <connection address> The "c=" field contains connection data. A session announcement must contain one "c=" field in each media description (see below) or a "c=" field at the session-level. */ cnt = sprintf(next, "c=IN IP4 %s\r\nb=AS:%i\r\nt=0 0\r\n", localAddr, bitRateInKilobits); // cnt = sprintf(next, "c=IN IP4 0.0.0.0\r\nb=AS:%i\r\nt=0 0\r\n",bitRateInKilobits); next += cnt; char *iodstr = new char[MAX_IOD_SIZE]; iodstr[0] = 0; u32 iodHandleSize=0; #ifndef WINCE int iodenclen = base64encode(stream->getIODHandle(iodHandleSize), iodHandleSize, (unsigned char*)iodstr, MAX_IOD_SIZE); #else int iodenclen = 0; #endif if(iodenclen<0 || iodenclen>=MAX_IOD_SIZE) iodenclen=0; iodstr[iodenclen] = 0; int streamcnt = es->size(); // #streams is without iod li = es->begin(); //a=control:*\r\n cnt = sprintf(next, "a=control:*\r\na=mpeg4-iod:\"data:application/mpeg4-iod;base64,%s\"\r\n", iodstr); next += cnt; // cnt = sprintf(next, "a=isma-compliance:1,1.0,1\r\na=range:npt=0-%5.5f\r\n", duration); next += cnt; if(includeRtxInfo && !es->empty()) { // write the grouping infos list < ESInfo*>::const_iterator ei=es->begin(); u32 lastMid=1; while(ei!=es->end()) { if((*ei)->isAudioStream() || (*ei)->isVisualStream() ) { rtx_group* group=stream->getRtxGroup( (*ei)->getStreamId(),groups); if(!group) { // no entry found, generate one group=new rtx_group(NACK,3000); group->midESInfo=lastMid++; group->rtx->mId=lastMid++; group->es=(*ei); group->rtx->ticks=(*ei)->getMediaTimeScale(); groups->push_back(group); } if(!group->rtx) { group->rtx=new rtx_info(NACK,3000); group->midESInfo=lastMid++; group->rtx->mId=lastMid++; group->es=(*ei); group->rtx->ticks=(*ei)->getMediaTimeScale(); } cnt=sprintf(next,"a=group:FID %u %u\r\n", group->midESInfo, group->rtx->mId); next+=cnt; } ++ei; } } int payloadType = SL_PAYLOAD_TYPE; u32 bw2=0; for (int i = 1; i <= streamcnt; i++) { u32 tid = (*li)->getStreamId(); u32 handlerType = (*li)->getHandlerType(); //const u8 *decoderConfig = (*li)->getEncodedDecoderConfig(); // u32 objectType=(*li)->getObjectType(); // u32 streamType = (*li)->getStreamType(); // u32 bufferSize=(*li)->getBufferSize(); u32 sze = 0; u8 volHeader[4096]; u8* newHeader=NULL; u8* src=NULL; uint width = 0, height = 0;uint bitrate=0; if ('/' == *filename) filename++; rtx_group* currentRtx=NULL; if(includeRtxInfo) currentRtx=stream->getRtxGroup(tid,groups); switch (handlerType) { case MP4VisualHandlerType: width = ((VideoESInfo*)(*li))->getWidth(); height = ((VideoESInfo*)(*li))->getHeight(); bitrate=((VideoESInfo*)(*li))->getAvgBandwidth(); if(tc && !perfectHit) { // check if tc say sth different if(tc->getDisplayHeight()!=0 && tc->getDisplayHeight() < height) height=tc->getDisplayHeight(); if(tc->getDisplayWidth()!=0 && tc->getDisplayWidth() < width) width=tc->getDisplayWidth(); bw2=tc->getNetworkCapacityInByte()*8; if(bw2==0) bw2=tc->getMaxDecoderBitRateInBit(); else if(tc->getMaxDecoderBitRateInBit() && tc->getMaxDecoderBitRateInBit() < bw2) { bw2=tc->getMaxDecoderBitRateInBit(); } u32 new_bitrate = width * height * 6; if (new_bitrate > bw2) new_bitrate = bw2; //reduce to given termCaps if (new_bitrate < bitrate) bitrate = new_bitrate; newHeader = MP4Encoder::createNewHeader((VideoESInfo*)(*li), new_bitrate, width, height, 300, (int)((VideoESInfo*)(*li))->getFPS(), &sze); } if(!newHeader) { sze = (*li)->getHeaders(&src); SDP::encodeDecoderConfig(volHeader, src, sze); } else { SDP::encodeDecoderConfig(volHeader,newHeader,sze); delete newHeader;newHeader=NULL; } cnt = sprintf(next, "m=video 0 RTP/AVP %i\r\nb=AS:%i\r\n" "a=rtpmap:%i MP4V-ES/%i\r\n" "a=control:trackID=%i\r\n" "a=cliprect:0,0,%i,%i\r\n" "a=fmtp:%i profile-level-id=1;config=%s\r\n" // StreamType=%i; "SizeLength=%i; " // "DTSDeltaLength=%i; config=%s\r\n" "a=mpeg4-esid:%i\r\n" "a=aspect-ratio=%6.6f\r\n" "a=frame-pattern=%s\r\n" "a=bframesamount=%f\r\n", payloadType, (bitrate / 1024), payloadType, (*li)->getMediaTimeScale(), tid, width, height, SL_PAYLOAD_TYPE, volHeader, // streamType, //sizeLength, // dtsDeltaLength, volHeader, tid, // "mpeg4-generic" ((VideoESInfo*)(*li))->getAspectRatio(), (((VideoESInfo*)(*li))->hasStaticFramePattern()?"static":"dynamic"), ((VideoESInfo*)(*li))->getAvgBFrameSize()); next += cnt; // add bframes and gop size for static frame pattern if(((VideoESInfo*)(*li))->hasStaticFramePattern()) { cnt = sprintf(next, "a=num-bframes %i\r\n" "a=gop-size %i\r\n", ((VideoESInfo*)(*li))->getNum_B_frames(), ((VideoESInfo*)(*li))->getGOP_size()); next+=cnt; } payloadType++; if( includeRtxInfo && currentRtx && currentRtx->rtx && currentRtx->rtx->state!=NONE) { u32 maxRtxDelay=3000; if( currentRtx->rtx && currentRtx->rtx->rtxTimeInMs>0) maxRtxDelay=currentRtx->rtx->rtxTimeInMs; else { currentRtx->rtx=new rtx_info(NACK,maxRtxDelay); // impossible code } cnt = sprintf(next, "a=rtcp-fb:%i %s\r\n" "a=mid:%u\r\n" // write the mid for the media "m=video 0 RTP/AVPF %i\r\n" "a=rtpmap:%i rtx/%u\r\n" "a=fmtp:%i apt=%i;rtx-time=%u\r\n" "a=mid:%u\r\n", payloadType-1, sRTXState[currentRtx->rtx->state], currentRtx->midESInfo, payloadType, payloadType, currentRtx->rtx->ticks, payloadType,(payloadType-1),maxRtxDelay, currentRtx->rtx->mId); next += cnt; currentRtx->rtx->payloadType=payloadType; payloadType++; } break; case MP4AudioHandlerType: // only send audio when TermCaps indicate that the client can handle audio if(!tc || (tc && tc->getNumAudioChannels()>0)) { // audio config still not correct u8 decoderConfig[4096]; src = NULL; payloadType=14; sze = (*li)->getHeaders(&src); SDP::encodeDecoderConfig(decoderConfig, src, sze); cnt = sprintf(next, "m=audio 0 RTP/AVP %i\r\nb=AS:%i\r\n" // payload "a=control:trackID=%i\r\n" // trackid "a=mpeg4-esid:%i\r\n" // esid "a=fmtp:%i DTSDeltaLength=%i; config=%s\r\n" "a=rtpmap:%i MPA/%i\r\n", payloadType,((*li)->getAvgBandwidth() / 1024), tid, tid, payloadType, dtsDeltaLength, decoderConfig, payloadType, (*li)->getMediaTimeScale()); next += cnt; payloadType++; if(includeRtxInfo) { u32 maxRtxDelay=3000; if( currentRtx->rtx && currentRtx->rtx->rtxTimeInMs>0) maxRtxDelay=currentRtx->rtx->rtxTimeInMs; else { currentRtx->rtx=new rtx_info(NACK,maxRtxDelay); } cnt = sprintf(next, "a=mid:%ui\r\n" // write the mid for the media "m=audio 0 RTP/AVPF %i\r\n" "a=rtpmap:%i rtx/%i\r\n" "a=fmtp:%i apt=%i;rtx-time=%ui\r\n" "a=mid:%i\r\n", currentRtx->midESInfo, payloadType, payloadType, currentRtx->rtx->ticks, payloadType,(payloadType-1),maxRtxDelay, currentRtx->rtx->mId); next += cnt; currentRtx->rtx->payloadType=payloadType; payloadType++; } } // if !tc... break; default: //application is not recognized by many players! /* cnt = sprintf(next, "m=application 0 RTP/AVP %i\r\n" "a=control:trackID=%i\r\n" "a=mpeg4-esid:%i\r\n" "a=fmtp:%i " // StreamType=%i; "// SizeLength=%i; " // "config=%s\r\n" // "DTSDeltaLength=%i; config=%s\r\n" "\r\na=rtpmap:%i %s\r\n", payloadType, tid, tid, payloadType, // streamType, //sizeLength, //dtsDeltaLength, decoderConfig, // payloadType, "X-MP4-ES/1000"); //mpeg4-generic next += cnt; payloadType++; */ ; } ++li; // increase list iterator if(src) delete src; } *next = 0; char *result = new char[strlen(buffer) + 1]; strcpy(result, buffer); delete [] iodstr; delete [] buffer; return result; };

bool SDP::parse (  const char *  sdp  )

Parse an SDP description. The field values may then be retrieved using other instance methods of this class. Currently, only the following SDP fields are understood, all other occuring fields are ignored: v=0 required to start a valid SDP description. s=_session_name_ session name; required to start a session description. a=control:_URL_ control URL. a=range:npt=_start_-_end_ media presentation time range in seconds (floating point). Warning: This function is not thread-safe! Returns: false if the given string does not contain a valid SDP description. Definition at line 83 of file SDP.cpp. { char *buf = new char[SDP_BUF_SIZE]; int bufsize = strlen(sdp)+1; if (bufsize > SDP_BUF_SIZE) { delete [] buf; return false; } strcpy(buf, sdp); struct session *sp = NULL; bool err = false; bool valid_version = false; char *bufend = buf + strlen(buf); // points to terminating '\0' char *p = buf; char *field, *value; do { /* ignore empty lines */ while (p < bufend && (*p == '\n' || *p == '\r')) p++; if (p >= bufend) break; field = p; if (++p >= bufend || *p != '=') { err = true; break; } /* value is anything up to the end of line or buffer */ value = ++p; while (p < bufend && *p != '\n' && *p != '\r') p++; *p++ = '\0'; switch (*field) { case 'v': if (strcmp(value, "0") == 0) valid_version = true; else err = true; break; case 's': sp = new struct session; sp->name.assign(value); sessionList.push_back(sp); break; case 'a': if (sp) { if (strncmp(value, "control:", 8) == 0) { sp->url.assign(value + 8); } else if (strncmp(value, "range:", 6) == 0) { char *p1 = strstr(value + 6, "npt="); if (p1) { p1 += 4; char *p2 = strchr(p1, '-'); if (p2) { *p2++ = '\0'; if (strlen(p2) > 0 && sscanf(p2, "%lf", &sp->nptEnd) != 1) err = true; } if (strlen(p1) > 0 && sscanf(p1, "%lf", &sp->nptStart) != 1) err = true; } } } break; } // switch } while (p < bufend); if (err || !valid_version) { clear(); delete [] buf; return false; } #if VITOOKI_DEBUG_LEVEL >= VITOOKI_DEBUG_FULL dprintf_full("SDP::parse() parsed %d session description(s):\n", sessionList.size()); for (list<struct session *>::iterator it = sessionList.begin(); it != sessionList.end(); it++) { dprintf_full(" name = %s, url = %s, nptStart = %lf, nptEnd = %lf\n", (*it)->name.c_str(), (*it)->url.c_str(), (*it)->nptStart, (*it)->nptEnd); } #endif delete [] buf; return true; }

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

• SDP.hpp
• SDP.cpp

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