| /********** |
| 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. |
| // Transcoder for ADUized MP3 frames |
| // Implementation |
| |
| #include "MP3ADUTranscoder.hh" |
| #include "MP3Internals.hh" |
| #include <string.h> |
| |
| MP3ADUTranscoder::MP3ADUTranscoder(UsageEnvironment& env, |
| unsigned outBitrate /* in kbps */, |
| FramedSource* inputSource) |
| : FramedFilter(env, inputSource), |
| fOutBitrate(outBitrate), |
| fAvailableBytesForBackpointer(0), |
| fOrigADU(new unsigned char[MAX_MP3_FRAME_SIZE]) { |
| } |
| |
| MP3ADUTranscoder::~MP3ADUTranscoder() { |
| delete[] fOrigADU; |
| } |
| |
| MP3ADUTranscoder* MP3ADUTranscoder::createNew(UsageEnvironment& env, |
| unsigned outBitrate /* in kbps */, |
| FramedSource* inputSource) { |
| // 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 MP3ADUTranscoder(env, outBitrate, inputSource); |
| } |
| |
| void MP3ADUTranscoder::getAttributes() const { |
| // Begin by getting the attributes from our input source: |
| fInputSource->getAttributes(); |
| |
| // Then modify them by appending the corrected bandwidth |
| char buffer[30]; |
| sprintf(buffer, " bandwidth %d", outBitrate()); |
| envir().appendToResultMsg(buffer); |
| } |
| |
| void MP3ADUTranscoder::doGetNextFrame() { |
| fInputSource->getNextFrame(fOrigADU, MAX_MP3_FRAME_SIZE, |
| afterGettingFrame, this, handleClosure, this); |
| } |
| |
| void MP3ADUTranscoder::afterGettingFrame(void* clientData, |
| unsigned numBytesRead, |
| unsigned numTruncatedBytes, |
| struct timeval presentationTime, |
| unsigned durationInMicroseconds) { |
| MP3ADUTranscoder* transcoder = (MP3ADUTranscoder*)clientData; |
| transcoder->afterGettingFrame1(numBytesRead, numTruncatedBytes, |
| presentationTime, durationInMicroseconds); |
| } |
| |
| void MP3ADUTranscoder::afterGettingFrame1(unsigned numBytesRead, |
| unsigned numTruncatedBytes, |
| struct timeval presentationTime, |
| unsigned durationInMicroseconds) { |
| fNumTruncatedBytes = numTruncatedBytes; // but can we handle this being >0? ##### |
| fPresentationTime = presentationTime; |
| fDurationInMicroseconds = durationInMicroseconds; |
| fFrameSize = TranscodeMP3ADU(fOrigADU, numBytesRead, fOutBitrate, |
| fTo, fMaxSize, fAvailableBytesForBackpointer); |
| if (fFrameSize == 0) { // internal error - bad ADU data? |
| handleClosure(); |
| return; |
| } |
| |
| // Call our own 'after getting' function. Because we're not a 'leaf' |
| // source, we can call this directly, without risking infinite recursion. |
| afterGetting(this); |
| } |