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// A source object for AMR audio files (as defined in RFC 4867, section 5)
19// Implementation
20
21#include "AMRAudioFileSource.hh"
22#include "InputFile.hh"
23#include "GroupsockHelper.hh"
24
25////////// AMRAudioFileSource //////////
26
27AMRAudioFileSource*
28AMRAudioFileSource::createNew(UsageEnvironment& env, char const* fileName) {
29 FILE* fid = NULL;
30 Boolean magicNumberOK = True;
31 do {
32
33 fid = OpenInputFile(env, fileName);
34 if (fid == NULL) break;
35
36 // Now, having opened the input file, read the first few bytes, to
37 // check the required 'magic number':
38 magicNumberOK = False; // until we learn otherwise
39 Boolean isWideband = False; // by default
40 unsigned numChannels = 1; // by default
41 char buf[100];
42 // Start with the first 6 bytes (the first 5 of which must be "#!AMR"):
43 if (fread(buf, 1, 6, fid) < 6) break;
44 if (strncmp(buf, "#!AMR", 5) != 0) break; // bad magic #
45 unsigned bytesRead = 6;
46
47 // The next bytes must be "\n", "-WB\n", "_MC1.0\n", or "-WB_MC1.0\n"
48 if (buf[5] == '-') {
49 // The next bytes must be "WB\n" or "WB_MC1.0\n"
50 if (fread(&buf[bytesRead], 1, 3, fid) < 3) break;
51 if (strncmp(&buf[bytesRead], "WB", 2) != 0) break; // bad magic #
52 isWideband = True;
53 bytesRead += 3;
54 }
55 if (buf[bytesRead-1] == '_') {
56 // The next bytes must be "MC1.0\n"
57 if (fread(&buf[bytesRead], 1, 6, fid) < 6) break;
58 if (strncmp(&buf[bytesRead], "MC1.0\n", 6) != 0) break; // bad magic #
59 bytesRead += 6;
60
61 // The next 4 bytes contain the number of channels:
62 char channelDesc[4];
63 if (fread(channelDesc, 1, 4, fid) < 4) break;
64 numChannels = channelDesc[3]&0xF;
65 } else if (buf[bytesRead-1] != '\n') {
66 break; // bad magic #
67 }
68
69 // If we get here, the magic number was OK:
70 magicNumberOK = True;
71
72#ifdef DEBUG
73 fprintf(stderr, "isWideband: %d, numChannels: %d\n",
74 isWideband, numChannels);
75#endif
76 return new AMRAudioFileSource(env, fid, isWideband, numChannels);
77 } while (0);
78
79 // An error occurred:
80 CloseInputFile(fid);
81 if (!magicNumberOK) {
82 env.setResultMsg("Bad (or nonexistent) AMR file header");
83 }
84 return NULL;
85}
86
87AMRAudioFileSource
88::AMRAudioFileSource(UsageEnvironment& env, FILE* fid,
89 Boolean isWideband, unsigned numChannels)
90 : AMRAudioSource(env, isWideband, numChannels),
91 fFid(fid) {
92}
93
94AMRAudioFileSource::~AMRAudioFileSource() {
95 CloseInputFile(fFid);
96}
97
98// The mapping from the "FT" field to frame size.
99// Values of 65535 are invalid.
100#define FT_INVALID 65535
101static unsigned short const frameSize[16] = {
102 12, 13, 15, 17,
103 19, 20, 26, 31,
104 5, FT_INVALID, FT_INVALID, FT_INVALID,
105 FT_INVALID, FT_INVALID, FT_INVALID, 0
106};
107static unsigned short const frameSizeWideband[16] = {
108 17, 23, 32, 36,
109 40, 46, 50, 58,
110 60, 5, FT_INVALID, FT_INVALID,
111 FT_INVALID, FT_INVALID, 0, 0
112};
113
114// Note: We should change the following to use asynchronous file reading, #####
115// as we now do with ByteStreamFileSource. #####
116void AMRAudioFileSource::doGetNextFrame() {
117 if (feof(fFid) || ferror(fFid)) {
118 handleClosure();
119 return;
120 }
121
122 // Begin by reading the 1-byte frame header (and checking it for validity)
123 while (1) {
124 if (fread(&fLastFrameHeader, 1, 1, fFid) < 1) {
125 handleClosure();
126 return;
127 }
128 if ((fLastFrameHeader&0x83) != 0) {
129#ifdef DEBUG
130 fprintf(stderr, "Invalid frame header 0x%02x (padding bits (0x83) are not zero)\n", fLastFrameHeader);
131#endif
132 } else {
133 unsigned char ft = (fLastFrameHeader&0x78)>>3;
134 fFrameSize = fIsWideband ? frameSizeWideband[ft] : frameSize[ft];
135 if (fFrameSize == FT_INVALID) {
136#ifdef DEBUG
137 fprintf(stderr, "Invalid FT field %d (from frame header 0x%02x)\n",
138 ft, fLastFrameHeader);
139#endif
140 } else {
141 // The frame header is OK
142#ifdef DEBUG
143 fprintf(stderr, "Valid frame header 0x%02x -> ft %d -> frame size %d\n", fLastFrameHeader, ft, fFrameSize);
144#endif
145 break;
146 }
147 }
148 }
149
150 // Next, read the frame-block into the buffer provided:
151 fFrameSize *= fNumChannels; // because multiple channels make up a frame-block
152 if (fFrameSize > fMaxSize) {
153 fNumTruncatedBytes = fFrameSize - fMaxSize;
154 fFrameSize = fMaxSize;
155 }
156 fFrameSize = fread(fTo, 1, fFrameSize, fFid);
157
158 // Set the 'presentation time':
159 if (fPresentationTime.tv_sec == 0 && fPresentationTime.tv_usec == 0) {
160 // This is the first frame, so use the current time:
161 gettimeofday(&fPresentationTime, NULL);
162 } else {
163 // Increment by the play time of the previous frame (20 ms)
164 unsigned uSeconds = fPresentationTime.tv_usec + 20000;
165 fPresentationTime.tv_sec += uSeconds/1000000;
166 fPresentationTime.tv_usec = uSeconds%1000000;
167 }
168
169 fDurationInMicroseconds = 20000; // each frame is 20 ms
170
171 // Switch to another task, and inform the reader that he has data:
172 nextTask() = envir().taskScheduler().scheduleDelayedTask(0,
173 (TaskFunc*)FramedSource::afterGetting, this);
174 }
175