1/**********
2This library is free software; you can redistribute it and/or modify it under
3the terms of the GNU Lesser General Public License as published by the
4Free Software Foundation; either version 3 of the License, or (at your
5option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
6
7This library is distributed in the hope that it will be useful, but WITHOUT
8ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
9FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
10more details.
11
12You should have received a copy of the GNU Lesser General Public License
13along with this library; if not, write to the Free Software Foundation, Inc.,
1451 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
15**********/
16// "liveMedia"
17// Copyright (c) 1996-2020 Live Networks, Inc. All rights reserved.
18// Transcoder for ADUized MP3 frames
19// Implementation
20
21#include "MP3ADUTranscoder.hh"
22#include "MP3Internals.hh"
23#include <string.h>
24
25MP3ADUTranscoder::MP3ADUTranscoder(UsageEnvironment& env,
26 unsigned outBitrate /* in kbps */,
27 FramedSource* inputSource)
28 : FramedFilter(env, inputSource),
29 fOutBitrate(outBitrate),
30 fAvailableBytesForBackpointer(0),
31 fOrigADU(new unsigned char[MAX_MP3_FRAME_SIZE]) {
32}
33
34MP3ADUTranscoder::~MP3ADUTranscoder() {
35 delete[] fOrigADU;
36}
37
38MP3ADUTranscoder* MP3ADUTranscoder::createNew(UsageEnvironment& env,
39 unsigned outBitrate /* in kbps */,
40 FramedSource* inputSource) {
41 // The source must be an MP3 ADU source:
42 if (strcmp(inputSource->MIMEtype(), "audio/MPA-ROBUST") != 0) {
43 env.setResultMsg(inputSource->name(), " is not an MP3 ADU source");
44 return NULL;
45 }
46
47 return new MP3ADUTranscoder(env, outBitrate, inputSource);
48}
49
50void MP3ADUTranscoder::getAttributes() const {
51 // Begin by getting the attributes from our input source:
52 fInputSource->getAttributes();
53
54 // Then modify them by appending the corrected bandwidth
55 char buffer[30];
56 sprintf(buffer, " bandwidth %d", outBitrate());
57 envir().appendToResultMsg(buffer);
58}
59
60void MP3ADUTranscoder::doGetNextFrame() {
61 fInputSource->getNextFrame(fOrigADU, MAX_MP3_FRAME_SIZE,
62 afterGettingFrame, this, handleClosure, this);
63}
64
65void MP3ADUTranscoder::afterGettingFrame(void* clientData,
66 unsigned numBytesRead,
67 unsigned numTruncatedBytes,
68 struct timeval presentationTime,
69 unsigned durationInMicroseconds) {
70 MP3ADUTranscoder* transcoder = (MP3ADUTranscoder*)clientData;
71 transcoder->afterGettingFrame1(numBytesRead, numTruncatedBytes,
72 presentationTime, durationInMicroseconds);
73}
74
75void MP3ADUTranscoder::afterGettingFrame1(unsigned numBytesRead,
76 unsigned numTruncatedBytes,
77 struct timeval presentationTime,
78 unsigned durationInMicroseconds) {
79 fNumTruncatedBytes = numTruncatedBytes; // but can we handle this being >0? #####
80 fPresentationTime = presentationTime;
81 fDurationInMicroseconds = durationInMicroseconds;
82 fFrameSize = TranscodeMP3ADU(fOrigADU, numBytesRead, fOutBitrate,
83 fTo, fMaxSize, fAvailableBytesForBackpointer);
84 if (fFrameSize == 0) { // internal error - bad ADU data?
85 handleClosure();
86 return;
87 }
88
89 // Call our own 'after getting' function. Because we're not a 'leaf'
90 // source, we can call this directly, without risking infinite recursion.
91 afterGetting(this);
92}
93