| /********** |
| This library is free software; you can redistribute it and/or modify it under |
| the terms of the GNU Lesser General Public License as published by the |
| Free Software Foundation; either version 3 of the License, or (at your |
| option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.) |
| |
| This library is distributed in the hope that it will be useful, but WITHOUT |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for |
| more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with this library; if not, write to the Free Software Foundation, Inc., |
| 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| **********/ |
| // "liveMedia" |
| // Copyright (c) 1996-2020 Live Networks, Inc. All rights reserved. |
| // RTP sink for 'ADUized' MP3 frames ("mpa-robust") |
| // Implementation |
| |
| #include "MP3ADURTPSink.hh" |
| |
| MP3ADURTPSink::MP3ADURTPSink(UsageEnvironment& env, Groupsock* RTPgs, |
| unsigned char RTPPayloadType) |
| : AudioRTPSink(env, RTPgs, RTPPayloadType, 90000, "MPA-ROBUST") { |
| } |
| |
| MP3ADURTPSink::~MP3ADURTPSink() { |
| } |
| |
| MP3ADURTPSink* |
| MP3ADURTPSink::createNew(UsageEnvironment& env, Groupsock* RTPgs, |
| unsigned char RTPPayloadType) { |
| return new MP3ADURTPSink(env, RTPgs, RTPPayloadType); |
| } |
| |
| static void badDataSize(UsageEnvironment& env, unsigned numBytesInFrame) { |
| env << "MP3ADURTPSink::doSpecialFrameHandling(): invalid size (" |
| << numBytesInFrame << ") of non-fragmented input ADU!\n"; |
| } |
| |
| void MP3ADURTPSink::doSpecialFrameHandling(unsigned fragmentationOffset, |
| unsigned char* frameStart, |
| unsigned numBytesInFrame, |
| struct timeval framePresentationTime, |
| unsigned numRemainingBytes) { |
| // If this is the first (or only) fragment of an ADU, then |
| // check the "ADU descriptor" (that should be at the front) for validity: |
| if (fragmentationOffset == 0) { |
| unsigned aduDescriptorSize; |
| |
| if (numBytesInFrame < 1) { |
| badDataSize(envir(), numBytesInFrame); |
| return; |
| } |
| if (frameStart[0]&0x40) { |
| // We have a 2-byte ADU descriptor |
| aduDescriptorSize = 2; |
| if (numBytesInFrame < 2) { |
| badDataSize(envir(), numBytesInFrame); |
| return; |
| } |
| fCurADUSize = ((frameStart[0]&~0xC0)<<8) | frameStart[1]; |
| } else { |
| // We have a 1-byte ADU descriptor |
| aduDescriptorSize = 1; |
| fCurADUSize = frameStart[0]&~0x80; |
| } |
| |
| if (frameStart[0]&0x80) { |
| envir() << "Unexpected \"C\" bit seen on non-fragment input ADU!\n"; |
| return; |
| } |
| |
| // Now, check whether the ADU size in the ADU descriptor is consistent |
| // with the total data size of (all fragments of) the input frame: |
| unsigned expectedADUSize = |
| fragmentationOffset + numBytesInFrame + numRemainingBytes |
| - aduDescriptorSize; |
| if (fCurADUSize != expectedADUSize) { |
| envir() << "MP3ADURTPSink::doSpecialFrameHandling(): Warning: Input ADU size " |
| << expectedADUSize << " (=" << fragmentationOffset |
| << "+" << numBytesInFrame << "+" << numRemainingBytes |
| << "-" << aduDescriptorSize |
| << ") did not match the value (" << fCurADUSize |
| << ") in the ADU descriptor!\n"; |
| fCurADUSize = expectedADUSize; |
| } |
| } else { |
| // This is the second (or subsequent) fragment. |
| // Insert a new ADU descriptor: |
| unsigned char aduDescriptor[2]; |
| aduDescriptor[0] = 0xC0|(fCurADUSize>>8); |
| aduDescriptor[1] = fCurADUSize&0xFF; |
| setSpecialHeaderBytes(aduDescriptor, 2); |
| } |
| |
| // Important: Also call our base class's doSpecialFrameHandling(), |
| // to set the packet's timestamp: |
| MultiFramedRTPSink::doSpecialFrameHandling(fragmentationOffset, |
| frameStart, numBytesInFrame, |
| framePresentationTime, |
| numRemainingBytes); |
| } |
| |
| unsigned MP3ADURTPSink::specialHeaderSize() const { |
| // Normally there's no special header. |
| // (The "ADU descriptor" is already present in the data.) |
| unsigned specialHeaderSize = 0; |
| |
| // However, if we're about to output the second (or subsequent) fragment |
| // of a fragmented ADU, then we need to insert a new ADU descriptor at |
| // the front of the packet: |
| if (curFragmentationOffset() > 0) { |
| specialHeaderSize = 2; |
| } |
| |
| return specialHeaderSize; |
| } |