| /********** |
| 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 2.1 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) 1996-2015 Live Networks, Inc. All rights reserved. |
| // 'ADU' MP3 streams (for improved loss-tolerance) |
| // Implementation |
| |
| #include "MP3ADU.hh" |
| #include "MP3ADUdescriptor.hh" |
| #include "MP3Internals.hh" |
| #include <string.h> |
| |
| #ifdef TEST_LOSS |
| #include "GroupsockHelper.hh" |
| #endif |
| |
| // Segment data structures, used in the implementation below: |
| |
| #define SegmentBufSize 2000 /* conservatively high */ |
| |
| class Segment { |
| public: |
| unsigned char buf[SegmentBufSize]; |
| unsigned char* dataStart() { return &buf[descriptorSize]; } |
| unsigned frameSize; // if it's a non-ADU frame |
| unsigned dataHere(); // if it's a non-ADU frame |
| |
| unsigned descriptorSize; |
| static unsigned const headerSize; |
| unsigned sideInfoSize, aduSize; |
| unsigned backpointer; |
| |
| struct timeval presentationTime; |
| unsigned durationInMicroseconds; |
| }; |
| |
| unsigned const Segment::headerSize = 4; |
| |
| #define SegmentQueueSize 20 |
| |
| class SegmentQueue { |
| public: |
| SegmentQueue(Boolean directionIsToADU, Boolean includeADUdescriptors) |
| : fDirectionIsToADU(directionIsToADU), |
| fIncludeADUdescriptors(includeADUdescriptors) { |
| reset(); |
| } |
| |
| Segment s[SegmentQueueSize]; |
| |
| unsigned headIndex() {return fHeadIndex;} |
| Segment& headSegment() {return s[fHeadIndex];} |
| |
| unsigned nextFreeIndex() {return fNextFreeIndex;} |
| Segment& nextFreeSegment() {return s[fNextFreeIndex];} |
| Boolean isEmpty() {return isEmptyOrFull() && totalDataSize() == 0;} |
| Boolean isFull() {return isEmptyOrFull() && totalDataSize() > 0;} |
| |
| static unsigned nextIndex(unsigned ix) {return (ix+1)%SegmentQueueSize;} |
| static unsigned prevIndex(unsigned ix) {return (ix+SegmentQueueSize-1)%SegmentQueueSize;} |
| |
| unsigned totalDataSize() {return fTotalDataSize;} |
| |
| void enqueueNewSegment(FramedSource* inputSource, FramedSource* usingSource); |
| |
| Boolean dequeue(); |
| |
| Boolean insertDummyBeforeTail(unsigned backpointer); |
| |
| void reset() { fHeadIndex = fNextFreeIndex = fTotalDataSize = 0; } |
| |
| private: |
| static void sqAfterGettingSegment(void* clientData, |
| unsigned numBytesRead, |
| unsigned numTruncatedBytes, |
| struct timeval presentationTime, |
| unsigned durationInMicroseconds); |
| |
| Boolean sqAfterGettingCommon(Segment& seg, unsigned numBytesRead); |
| Boolean isEmptyOrFull() {return headIndex() == nextFreeIndex();} |
| |
| unsigned fHeadIndex, fNextFreeIndex, fTotalDataSize; |
| |
| // The following is used for asynchronous reads: |
| FramedSource* fUsingSource; |
| |
| // This tells us whether the direction in which we're being used |
| // is MP3->ADU, or vice-versa. (This flag is used for debugging output.) |
| Boolean fDirectionIsToADU; |
| |
| // The following is true iff we're used to enqueue incoming |
| // ADU frames, and these have an ADU descriptor in front |
| Boolean fIncludeADUdescriptors; |
| }; |
| |
| ////////// ADUFromMP3Source ////////// |
| |
| ADUFromMP3Source::ADUFromMP3Source(UsageEnvironment& env, |
| FramedSource* inputSource, |
| Boolean includeADUdescriptors) |
| : FramedFilter(env, inputSource), |
| fAreEnqueueingMP3Frame(False), |
| fSegments(new SegmentQueue(True /* because we're MP3->ADU */, |
| False /*no descriptors in incoming frames*/)), |
| fIncludeADUdescriptors(includeADUdescriptors), |
| fTotalDataSizeBeforePreviousRead(0), fScale(1), fFrameCounter(0) { |
| } |
| |
| ADUFromMP3Source::~ADUFromMP3Source() { |
| delete fSegments; |
| } |
| |
| |
| char const* ADUFromMP3Source::MIMEtype() const { |
| return "audio/MPA-ROBUST"; |
| } |
| |
| ADUFromMP3Source* ADUFromMP3Source::createNew(UsageEnvironment& env, |
| FramedSource* inputSource, |
| Boolean includeADUdescriptors) { |
| // The source must be a MPEG audio source: |
| if (strcmp(inputSource->MIMEtype(), "audio/MPEG") != 0) { |
| env.setResultMsg(inputSource->name(), " is not an MPEG audio source"); |
| return NULL; |
| } |
| |
| return new ADUFromMP3Source(env, inputSource, includeADUdescriptors); |
| } |
| |
| void ADUFromMP3Source::resetInput() { |
| fSegments->reset(); |
| } |
| |
| Boolean ADUFromMP3Source::setScaleFactor(int scale) { |
| if (scale < 1) return False; |
| fScale = scale; |
| return True; |
| } |
| |
| void ADUFromMP3Source::doGetNextFrame() { |
| if (!fAreEnqueueingMP3Frame) { |
| // Arrange to enqueue a new MP3 frame: |
| fTotalDataSizeBeforePreviousRead = fSegments->totalDataSize(); |
| fAreEnqueueingMP3Frame = True; |
| fSegments->enqueueNewSegment(fInputSource, this); |
| } else { |
| // Deliver an ADU from a previously-read MP3 frame: |
| fAreEnqueueingMP3Frame = False; |
| |
| if (!doGetNextFrame1()) { |
| // An internal error occurred; act as if our source went away: |
| handleClosure(); |
| } |
| } |
| } |
| |
| Boolean ADUFromMP3Source::doGetNextFrame1() { |
| // First, check whether we have enough previously-read data to output an |
| // ADU for the last-read MP3 frame: |
| unsigned tailIndex; |
| Segment* tailSeg; |
| Boolean needMoreData; |
| |
| if (fSegments->isEmpty()) { |
| needMoreData = True; |
| tailSeg = NULL; tailIndex = 0; // unneeded, but stops compiler warnings |
| } else { |
| tailIndex = SegmentQueue::prevIndex(fSegments->nextFreeIndex()); |
| tailSeg = &(fSegments->s[tailIndex]); |
| |
| needMoreData |
| = fTotalDataSizeBeforePreviousRead < tailSeg->backpointer // bp points back too far |
| || tailSeg->backpointer + tailSeg->dataHere() < tailSeg->aduSize; // not enough data |
| } |
| |
| if (needMoreData) { |
| // We don't have enough data to output an ADU from the last-read MP3 |
| // frame, so need to read another one and try again: |
| doGetNextFrame(); |
| return True; |
| } |
| |
| // Output an ADU from the tail segment: |
| fFrameSize = tailSeg->headerSize+tailSeg->sideInfoSize+tailSeg->aduSize; |
| fPresentationTime = tailSeg->presentationTime; |
| fDurationInMicroseconds = tailSeg->durationInMicroseconds; |
| unsigned descriptorSize |
| = fIncludeADUdescriptors ? ADUdescriptor::computeSize(fFrameSize) : 0; |
| #ifdef DEBUG |
| fprintf(stderr, "m->a:outputting ADU %d<-%d, nbr:%d, sis:%d, dh:%d, (descriptor size: %d)\n", tailSeg->aduSize, tailSeg->backpointer, fFrameSize, tailSeg->sideInfoSize, tailSeg->dataHere(), descriptorSize); |
| #endif |
| if (descriptorSize + fFrameSize > fMaxSize) { |
| envir() << "ADUFromMP3Source::doGetNextFrame1(): not enough room (" |
| << descriptorSize + fFrameSize << ">" |
| << fMaxSize << ")\n"; |
| fFrameSize = 0; |
| return False; |
| } |
| |
| unsigned char* toPtr = fTo; |
| // output the ADU descriptor: |
| if (fIncludeADUdescriptors) { |
| fFrameSize += ADUdescriptor::generateDescriptor(toPtr, fFrameSize); |
| } |
| |
| // output header and side info: |
| memmove(toPtr, tailSeg->dataStart(), |
| tailSeg->headerSize + tailSeg->sideInfoSize); |
| toPtr += tailSeg->headerSize + tailSeg->sideInfoSize; |
| |
| // go back to the frame that contains the start of our data: |
| unsigned offset = 0; |
| unsigned i = tailIndex; |
| unsigned prevBytes = tailSeg->backpointer; |
| while (prevBytes > 0) { |
| i = SegmentQueue::prevIndex(i); |
| unsigned dataHere = fSegments->s[i].dataHere(); |
| if (dataHere < prevBytes) { |
| prevBytes -= dataHere; |
| } else { |
| offset = dataHere - prevBytes; |
| break; |
| } |
| } |
| |
| // dequeue any segments that we no longer need: |
| while (fSegments->headIndex() != i) { |
| fSegments->dequeue(); // we're done with it |
| } |
| |
| unsigned bytesToUse = tailSeg->aduSize; |
| while (bytesToUse > 0) { |
| Segment& seg = fSegments->s[i]; |
| unsigned char* fromPtr |
| = &seg.dataStart()[seg.headerSize + seg.sideInfoSize + offset]; |
| unsigned dataHere = seg.dataHere() - offset; |
| unsigned bytesUsedHere = dataHere < bytesToUse ? dataHere : bytesToUse; |
| memmove(toPtr, fromPtr, bytesUsedHere); |
| bytesToUse -= bytesUsedHere; |
| toPtr += bytesUsedHere; |
| offset = 0; |
| i = SegmentQueue::nextIndex(i); |
| } |
| |
| |
| if (fFrameCounter++%fScale == 0) { |
| // Call our own 'after getting' function. Because we're not a 'leaf' |
| // source, we can call this directly, without risking infinite recursion. |
| afterGetting(this); |
| } else { |
| // Don't use this frame; get another one: |
| doGetNextFrame(); |
| } |
| |
| return True; |
| } |
| |
| |
| ////////// MP3FromADUSource ////////// |
| |
| MP3FromADUSource::MP3FromADUSource(UsageEnvironment& env, |
| FramedSource* inputSource, |
| Boolean includeADUdescriptors) |
| : FramedFilter(env, inputSource), |
| fAreEnqueueingADU(False), |
| fSegments(new SegmentQueue(False /* because we're ADU->MP3 */, |
| includeADUdescriptors)) { |
| } |
| |
| MP3FromADUSource::~MP3FromADUSource() { |
| delete fSegments; |
| } |
| |
| char const* MP3FromADUSource::MIMEtype() const { |
| return "audio/MPEG"; |
| } |
| |
| MP3FromADUSource* MP3FromADUSource::createNew(UsageEnvironment& env, |
| FramedSource* inputSource, |
| Boolean includeADUdescriptors) { |
| // The source must be an MP3 ADU source: |
| if (strcmp(inputSource->MIMEtype(), "audio/MPA-ROBUST") != 0) { |
| env.setResultMsg(inputSource->name(), " is not an MP3 ADU source"); |
| return NULL; |
| } |
| |
| return new MP3FromADUSource(env, inputSource, includeADUdescriptors); |
| } |
| |
| |
| void MP3FromADUSource::doGetNextFrame() { |
| if (fAreEnqueueingADU) insertDummyADUsIfNecessary(); |
| fAreEnqueueingADU = False; |
| |
| if (needToGetAnADU()) { |
| // Before returning a frame, we must enqueue at least one ADU: |
| #ifdef TEST_LOSS |
| NOTE: This code no longer works, because it uses synchronous reads, |
| which are no longer supported. |
| static unsigned const framesPerPacket = 10; |
| static unsigned const frameCount = 0; |
| static Boolean packetIsLost; |
| while (1) { |
| if ((frameCount++)%framesPerPacket == 0) { |
| packetIsLost = (our_random()%10 == 0); // simulate 10% packet loss ##### |
| } |
| |
| if (packetIsLost) { |
| // Read and discard the next input frame (that would be part of |
| // a lost packet): |
| Segment dummySegment; |
| unsigned numBytesRead; |
| struct timeval presentationTime; |
| // (this works only if the source can be read synchronously) |
| fInputSource->syncGetNextFrame(dummySegment.buf, |
| sizeof dummySegment.buf, numBytesRead, |
| presentationTime); |
| } else { |
| break; // from while (1) |
| } |
| } |
| #endif |
| |
| fAreEnqueueingADU = True; |
| fSegments->enqueueNewSegment(fInputSource, this); |
| } else { |
| // Return a frame now: |
| generateFrameFromHeadADU(); |
| // sets fFrameSize, fPresentationTime, and fDurationInMicroseconds |
| |
| // Call our own 'after getting' function. Because we're not a 'leaf' |
| // source, we can call this directly, without risking infinite recursion. |
| afterGetting(this); |
| } |
| } |
| |
| Boolean MP3FromADUSource::needToGetAnADU() { |
| // Check whether we need to first enqueue a new ADU before we |
| // can generate a frame for our head ADU. |
| Boolean needToEnqueue = True; |
| |
| if (!fSegments->isEmpty()) { |
| unsigned index = fSegments->headIndex(); |
| Segment* seg = &(fSegments->headSegment()); |
| int const endOfHeadFrame = (int) seg->dataHere(); |
| unsigned frameOffset = 0; |
| |
| while (1) { |
| int endOfData = frameOffset - seg->backpointer + seg->aduSize; |
| if (endOfData >= endOfHeadFrame) { |
| // We already have enough data to generate a frame |
| needToEnqueue = False; |
| break; |
| } |
| |
| frameOffset += seg->dataHere(); |
| index = SegmentQueue::nextIndex(index); |
| if (index == fSegments->nextFreeIndex()) break; |
| seg = &(fSegments->s[index]); |
| } |
| } |
| |
| return needToEnqueue; |
| } |
| |
| void MP3FromADUSource::insertDummyADUsIfNecessary() { |
| if (fSegments->isEmpty()) return; // shouldn't happen |
| |
| // The tail segment (ADU) is assumed to have been recently |
| // enqueued. If its backpointer would overlap the data |
| // of the previous ADU, then we need to insert one or more |
| // empty, 'dummy' ADUs ahead of it. (This situation should occur |
| // only if an intermediate ADU was lost.) |
| |
| unsigned tailIndex |
| = SegmentQueue::prevIndex(fSegments->nextFreeIndex()); |
| Segment* tailSeg = &(fSegments->s[tailIndex]); |
| |
| while (1) { |
| unsigned prevADUend; // relative to the start of the new ADU |
| if (fSegments->headIndex() != tailIndex) { |
| // there is a previous segment |
| unsigned prevIndex = SegmentQueue::prevIndex(tailIndex); |
| Segment& prevSegment = fSegments->s[prevIndex]; |
| prevADUend = prevSegment.dataHere() + prevSegment.backpointer; |
| if (prevSegment.aduSize > prevADUend) { |
| // shouldn't happen if the previous ADU was well-formed |
| prevADUend = 0; |
| } else { |
| prevADUend -= prevSegment.aduSize; |
| } |
| } else { |
| prevADUend = 0; |
| } |
| |
| if (tailSeg->backpointer > prevADUend) { |
| // We need to insert a dummy ADU in front of the tail |
| #ifdef DEBUG |
| fprintf(stderr, "a->m:need to insert a dummy ADU (%d, %d, %d) [%d, %d]\n", tailSeg->backpointer, prevADUend, tailSeg->dataHere(), fSegments->headIndex(), fSegments->nextFreeIndex()); |
| #endif |
| tailIndex = fSegments->nextFreeIndex(); |
| if (!fSegments->insertDummyBeforeTail(prevADUend)) return; |
| tailSeg = &(fSegments->s[tailIndex]); |
| } else { |
| break; // no more dummy ADUs need to be inserted |
| } |
| } |
| } |
| |
| Boolean MP3FromADUSource::generateFrameFromHeadADU() { |
| // Output a frame for the head ADU: |
| if (fSegments->isEmpty()) return False; |
| unsigned index = fSegments->headIndex(); |
| Segment* seg = &(fSegments->headSegment()); |
| #ifdef DEBUG |
| fprintf(stderr, "a->m:outputting frame for %d<-%d (fs %d, dh %d), (descriptorSize: %d)\n", seg->aduSize, seg->backpointer, seg->frameSize, seg->dataHere(), seg->descriptorSize); |
| #endif |
| unsigned char* toPtr = fTo; |
| |
| // output header and side info: |
| fFrameSize = seg->frameSize; |
| fPresentationTime = seg->presentationTime; |
| fDurationInMicroseconds = seg->durationInMicroseconds; |
| memmove(toPtr, seg->dataStart(), seg->headerSize + seg->sideInfoSize); |
| toPtr += seg->headerSize + seg->sideInfoSize; |
| |
| // zero out the rest of the frame, in case ADU data doesn't fill it all in |
| unsigned bytesToZero = seg->dataHere(); |
| for (unsigned i = 0; i < bytesToZero; ++i) { |
| toPtr[i] = '\0'; |
| } |
| |
| // Fill in the frame with appropriate ADU data from this and |
| // subsequent ADUs: |
| unsigned frameOffset = 0; |
| unsigned toOffset = 0; |
| unsigned const endOfHeadFrame = seg->dataHere(); |
| |
| while (toOffset < endOfHeadFrame) { |
| int startOfData = frameOffset - seg->backpointer; |
| if (startOfData > (int)endOfHeadFrame) break; // no more ADUs needed |
| |
| int endOfData = startOfData + seg->aduSize; |
| if (endOfData > (int)endOfHeadFrame) { |
| endOfData = endOfHeadFrame; |
| } |
| |
| unsigned fromOffset; |
| if (startOfData <= (int)toOffset) { |
| fromOffset = toOffset - startOfData; |
| startOfData = toOffset; |
| if (endOfData < startOfData) endOfData = startOfData; |
| } else { |
| fromOffset = 0; |
| |
| // we may need some padding bytes beforehand |
| unsigned bytesToZero = startOfData - toOffset; |
| #ifdef DEBUG |
| if (bytesToZero > 0) fprintf(stderr, "a->m:outputting %d zero bytes (%d, %d, %d, %d)\n", bytesToZero, startOfData, toOffset, frameOffset, seg->backpointer); |
| #endif |
| toOffset += bytesToZero; |
| } |
| |
| unsigned char* fromPtr |
| = &seg->dataStart()[seg->headerSize + seg->sideInfoSize + fromOffset]; |
| unsigned bytesUsedHere = endOfData - startOfData; |
| #ifdef DEBUG |
| if (bytesUsedHere > 0) fprintf(stderr, "a->m:outputting %d bytes from %d<-%d\n", bytesUsedHere, seg->aduSize, seg->backpointer); |
| #endif |
| memmove(toPtr + toOffset, fromPtr, bytesUsedHere); |
| toOffset += bytesUsedHere; |
| |
| frameOffset += seg->dataHere(); |
| index = SegmentQueue::nextIndex(index); |
| if (index == fSegments->nextFreeIndex()) break; |
| seg = &(fSegments->s[index]); |
| } |
| |
| fSegments->dequeue(); |
| |
| return True; |
| } |
| |
| |
| ////////// Segment ////////// |
| |
| unsigned Segment::dataHere() { |
| int result = frameSize - (headerSize + sideInfoSize); |
| if (result < 0) { |
| return 0; |
| } |
| |
| return (unsigned)result; |
| } |
| |
| ////////// SegmentQueue ////////// |
| |
| void SegmentQueue::enqueueNewSegment(FramedSource* inputSource, |
| FramedSource* usingSource) { |
| if (isFull()) { |
| usingSource->envir() << "SegmentQueue::enqueueNewSegment() overflow\n"; |
| usingSource->handleClosure(); |
| return; |
| } |
| |
| fUsingSource = usingSource; |
| |
| Segment& seg = nextFreeSegment(); |
| inputSource->getNextFrame(seg.buf, sizeof seg.buf, |
| sqAfterGettingSegment, this, |
| FramedSource::handleClosure, usingSource); |
| } |
| |
| void SegmentQueue::sqAfterGettingSegment(void* clientData, |
| unsigned numBytesRead, |
| unsigned /*numTruncatedBytes*/, |
| struct timeval presentationTime, |
| unsigned durationInMicroseconds) { |
| SegmentQueue* segQueue = (SegmentQueue*)clientData; |
| Segment& seg = segQueue->nextFreeSegment(); |
| |
| seg.presentationTime = presentationTime; |
| seg.durationInMicroseconds = durationInMicroseconds; |
| |
| if (segQueue->sqAfterGettingCommon(seg, numBytesRead)) { |
| #ifdef DEBUG |
| char const* direction = segQueue->fDirectionIsToADU ? "m->a" : "a->m"; |
| fprintf(stderr, "%s:read frame %d<-%d, fs:%d, sis:%d, dh:%d, (descriptor size: %d)\n", direction, seg.aduSize, seg.backpointer, seg.frameSize, seg.sideInfoSize, seg.dataHere(), seg.descriptorSize); |
| #endif |
| } |
| |
| // Continue our original calling source where it left off: |
| segQueue->fUsingSource->doGetNextFrame(); |
| } |
| |
| // Common code called after a new segment is enqueued |
| Boolean SegmentQueue::sqAfterGettingCommon(Segment& seg, |
| unsigned numBytesRead) { |
| unsigned char* fromPtr = seg.buf; |
| |
| if (fIncludeADUdescriptors) { |
| // The newly-read data is assumed to be an ADU with a descriptor |
| // in front |
| (void)ADUdescriptor::getRemainingFrameSize(fromPtr); |
| seg.descriptorSize = (unsigned)(fromPtr-seg.buf); |
| } else { |
| seg.descriptorSize = 0; |
| } |
| |
| // parse the MP3-specific info in the frame to get the ADU params |
| unsigned hdr; |
| MP3SideInfo sideInfo; |
| if (!GetADUInfoFromMP3Frame(fromPtr, numBytesRead, |
| hdr, seg.frameSize, |
| sideInfo, seg.sideInfoSize, |
| seg.backpointer, seg.aduSize)) { |
| return False; |
| } |
| |
| // If we've just read an ADU (rather than a regular MP3 frame), then use the |
| // entire "numBytesRead" data for the 'aduSize', so that we include any |
| // 'ancillary data' that may be present at the end of the ADU: |
| if (!fDirectionIsToADU) { |
| unsigned newADUSize |
| = numBytesRead - seg.descriptorSize - 4/*header size*/ - seg.sideInfoSize; |
| if (newADUSize > seg.aduSize) seg.aduSize = newADUSize; |
| } |
| fTotalDataSize += seg.dataHere(); |
| fNextFreeIndex = nextIndex(fNextFreeIndex); |
| |
| return True; |
| } |
| |
| Boolean SegmentQueue::dequeue() { |
| if (isEmpty()) { |
| fUsingSource->envir() << "SegmentQueue::dequeue(): underflow!\n"; |
| return False; |
| } |
| |
| Segment& seg = s[headIndex()]; |
| fTotalDataSize -= seg.dataHere(); |
| fHeadIndex = nextIndex(fHeadIndex); |
| return True; |
| } |
| |
| Boolean SegmentQueue::insertDummyBeforeTail(unsigned backpointer) { |
| if (isEmptyOrFull()) return False; |
| |
| // Copy the current tail segment to its new position, then modify the |
| // old tail segment to be a 'dummy' ADU |
| |
| unsigned newTailIndex = nextFreeIndex(); |
| Segment& newTailSeg = s[newTailIndex]; |
| |
| unsigned oldTailIndex = prevIndex(newTailIndex); |
| Segment& oldTailSeg = s[oldTailIndex]; |
| |
| newTailSeg = oldTailSeg; // structure copy |
| |
| // Begin by setting (replacing) the ADU descriptor of the dummy ADU: |
| unsigned char* ptr = oldTailSeg.buf; |
| if (fIncludeADUdescriptors) { |
| unsigned remainingFrameSize |
| = oldTailSeg.headerSize + oldTailSeg.sideInfoSize + 0 /* 0-size ADU */; |
| unsigned currentDescriptorSize = oldTailSeg.descriptorSize; |
| |
| if (currentDescriptorSize == 2) { |
| ADUdescriptor::generateTwoByteDescriptor(ptr, remainingFrameSize); |
| } else { |
| (void)ADUdescriptor::generateDescriptor(ptr, remainingFrameSize); |
| } |
| } |
| |
| // Then zero out the side info of the dummy frame: |
| if (!ZeroOutMP3SideInfo(ptr, oldTailSeg.frameSize, |
| backpointer)) return False; |
| |
| unsigned dummyNumBytesRead |
| = oldTailSeg.descriptorSize + 4/*header size*/ + oldTailSeg.sideInfoSize; |
| return sqAfterGettingCommon(oldTailSeg, dummyNumBytesRead); |
| } |