00001 /********** 00002 This library is free software; you can redistribute it and/or modify it under 00003 the terms of the GNU Lesser General Public License as published by the 00004 Free Software Foundation; either version 2.1 of the License, or (at your 00005 option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.) 00006 00007 This library is distributed in the hope that it will be useful, but WITHOUT 00008 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 00009 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for 00010 more details. 00011 00012 You should have received a copy of the GNU Lesser General Public License 00013 along with this library; if not, write to the Free Software Foundation, Inc., 00014 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 00015 **********/ 00016 // "liveMedia" 00017 // Copyright (c) 1996-2005 Live Networks, Inc. All rights reserved. 00018 // RTP sink for MPEG audio (RFC 2250) 00019 // Implementation 00020 00021 #include "MPEG1or2AudioRTPSink.hh" 00022 00023 MPEG1or2AudioRTPSink::MPEG1or2AudioRTPSink(UsageEnvironment& env, Groupsock* RTPgs) 00024 : AudioRTPSink(env, RTPgs, 14, 90000, "MPA") { 00025 } 00026 00027 MPEG1or2AudioRTPSink::~MPEG1or2AudioRTPSink() { 00028 } 00029 00030 MPEG1or2AudioRTPSink* 00031 MPEG1or2AudioRTPSink::createNew(UsageEnvironment& env, Groupsock* RTPgs) { 00032 return new MPEG1or2AudioRTPSink(env, RTPgs); 00033 } 00034 00035 void MPEG1or2AudioRTPSink::doSpecialFrameHandling(unsigned fragmentationOffset, 00036 unsigned char* frameStart, 00037 unsigned numBytesInFrame, 00038 struct timeval frameTimestamp, 00039 unsigned numRemainingBytes) { 00040 // If this is the 1st frame in the 1st packet, set the RTP 'M' (marker) 00041 // bit (because this is considered the start of a talk spurt): 00042 if (isFirstPacket() && isFirstFrameInPacket()) { 00043 setMarkerBit(); 00044 } 00045 00046 // If this is the first frame in the packet, set the lower half of the 00047 // audio-specific header (to the "fragmentationOffset"): 00048 if (isFirstFrameInPacket()) { 00049 setSpecialHeaderWord(fragmentationOffset&0xFFFF); 00050 } 00051 00052 // Important: Also call our base class's doSpecialFrameHandling(), 00053 // to set the packet's timestamp: 00054 MultiFramedRTPSink::doSpecialFrameHandling(fragmentationOffset, 00055 frameStart, numBytesInFrame, 00056 frameTimestamp, 00057 numRemainingBytes); 00058 } 00059 00060 unsigned MPEG1or2AudioRTPSink::specialHeaderSize() const { 00061 // There's a 4 byte special audio header: 00062 return 4; 00063 }
1.5.5