120 lines
4.2 KiB
C++
Executable File
120 lines
4.2 KiB
C++
Executable File
/**********
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This library is free software; you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License as published by the
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Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
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This library is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
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more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this library; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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**********/
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// "liveMedia"
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// Copyright (c) 1996-2016 Live Networks, Inc. All rights reserved.
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// RTP sink for 'ADUized' MP3 frames ("mpa-robust")
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// Implementation
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#include "MP3ADURTPSink.hh"
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MP3ADURTPSink::MP3ADURTPSink(UsageEnvironment& env, Groupsock* RTPgs,
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unsigned char RTPPayloadType)
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: AudioRTPSink(env, RTPgs, RTPPayloadType, 90000, "MPA-ROBUST") {
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}
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MP3ADURTPSink::~MP3ADURTPSink() {
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}
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MP3ADURTPSink*
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MP3ADURTPSink::createNew(UsageEnvironment& env, Groupsock* RTPgs,
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unsigned char RTPPayloadType) {
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return new MP3ADURTPSink(env, RTPgs, RTPPayloadType);
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}
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static void badDataSize(UsageEnvironment& env, unsigned numBytesInFrame) {
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env << "MP3ADURTPSink::doSpecialFrameHandling(): invalid size ("
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<< numBytesInFrame << ") of non-fragmented input ADU!\n";
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}
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void MP3ADURTPSink::doSpecialFrameHandling(unsigned fragmentationOffset,
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unsigned char* frameStart,
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unsigned numBytesInFrame,
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struct timeval framePresentationTime,
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unsigned numRemainingBytes) {
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// If this is the first (or only) fragment of an ADU, then
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// check the "ADU descriptor" (that should be at the front) for validity:
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if (fragmentationOffset == 0) {
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unsigned aduDescriptorSize;
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if (numBytesInFrame < 1) {
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badDataSize(envir(), numBytesInFrame);
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return;
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}
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if (frameStart[0]&0x40) {
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// We have a 2-byte ADU descriptor
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aduDescriptorSize = 2;
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if (numBytesInFrame < 2) {
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badDataSize(envir(), numBytesInFrame);
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return;
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}
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fCurADUSize = ((frameStart[0]&~0xC0)<<8) | frameStart[1];
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} else {
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// We have a 1-byte ADU descriptor
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aduDescriptorSize = 1;
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fCurADUSize = frameStart[0]&~0x80;
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}
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if (frameStart[0]&0x80) {
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envir() << "Unexpected \"C\" bit seen on non-fragment input ADU!\n";
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return;
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}
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// Now, check whether the ADU size in the ADU descriptor is consistent
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// with the total data size of (all fragments of) the input frame:
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unsigned expectedADUSize =
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fragmentationOffset + numBytesInFrame + numRemainingBytes
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- aduDescriptorSize;
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if (fCurADUSize != expectedADUSize) {
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envir() << "MP3ADURTPSink::doSpecialFrameHandling(): Warning: Input ADU size "
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<< expectedADUSize << " (=" << fragmentationOffset
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<< "+" << numBytesInFrame << "+" << numRemainingBytes
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<< "-" << aduDescriptorSize
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<< ") did not match the value (" << fCurADUSize
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<< ") in the ADU descriptor!\n";
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fCurADUSize = expectedADUSize;
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}
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} else {
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// This is the second (or subsequent) fragment.
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// Insert a new ADU descriptor:
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unsigned char aduDescriptor[2];
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aduDescriptor[0] = 0xC0|(fCurADUSize>>8);
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aduDescriptor[1] = fCurADUSize&0xFF;
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setSpecialHeaderBytes(aduDescriptor, 2);
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}
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// Important: Also call our base class's doSpecialFrameHandling(),
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// to set the packet's timestamp:
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MultiFramedRTPSink::doSpecialFrameHandling(fragmentationOffset,
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frameStart, numBytesInFrame,
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framePresentationTime,
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numRemainingBytes);
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}
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unsigned MP3ADURTPSink::specialHeaderSize() const {
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// Normally there's no special header.
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// (The "ADU descriptor" is already present in the data.)
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unsigned specialHeaderSize = 0;
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// However, if we're about to output the second (or subsequent) fragment
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// of a fragmented ADU, then we need to insert a new ADU descriptor at
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// the front of the packet:
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if (curFragmentationOffset() > 0) {
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specialHeaderSize = 2;
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}
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return specialHeaderSize;
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}
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