1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
/**********
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.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
**********/
// "liveMedia"
// Copyright (c) 1996-2005 Live Networks, Inc. All rights reserved.
// A source object for AMR audio files (as defined in RFC 3267, section 5)
// Implementation
#include "AMRAudioFileSource.hh"
#include "InputFile.hh"
#include "GroupsockHelper.hh"
////////// AMRAudioFileSource //////////
AMRAudioFileSource*
AMRAudioFileSource::createNew(UsageEnvironment& env, char const* fileName) {
FILE* fid = NULL;
Boolean magicNumberOK = True;
do {
fid = OpenInputFile(env, fileName);
if (fid == NULL) break;
// Now, having opened the input file, read the first few bytes, to
// check the required 'magic number':
magicNumberOK = False; // until we learn otherwise
Boolean isWideband = False; // by default
unsigned numChannels = 1; // by default
char buf[100];
// Start with the first 6 bytes (the first 5 of which must be "#!AMR"):
if (fread(buf, 1, 6, fid) < 6) break;
if (strncmp(buf, "#!AMR", 5) != 0) break; // bad magic #
unsigned bytesRead = 6;
// The next bytes must be "\n", "-WB\n", "_MC1.0\n", or "-WB_MC1.0\n"
if (buf[5] == '-') {
// The next bytes must be "WB\n" or "WB_MC1.0\n"
if (fread(&buf[bytesRead], 1, 3, fid) < 3) break;
if (strncmp(&buf[bytesRead], "WB", 2) != 0) break; // bad magic #
isWideband = True;
bytesRead += 3;
}
if (buf[bytesRead-1] == '_') {
// The next bytes must be "MC1.0\n"
if (fread(&buf[bytesRead], 1, 6, fid) < 6) break;
if (strncmp(&buf[bytesRead], "MC1.0\n", 6) != 0) break; // bad magic #
bytesRead += 6;
// The next 4 bytes contain the number of channels:
char channelDesc[4];
if (fread(channelDesc, 1, 4, fid) < 4) break;
numChannels = channelDesc[3]&0xF;
} else if (buf[bytesRead-1] != '\n') {
break; // bad magic #
}
// If we get here, the magic number was OK:
magicNumberOK = True;
#ifdef DEBUG
fprintf(stderr, "isWideband: %d, numChannels: %d\n",
isWideband, numChannels);
#endif
return new AMRAudioFileSource(env, fid, isWideband, numChannels);
} while (0);
// An error occurred:
CloseInputFile(fid);
if (!magicNumberOK) {
env.setResultMsg("Bad (or nonexistent) AMR file header");
}
return NULL;
}
AMRAudioFileSource
::AMRAudioFileSource(UsageEnvironment& env, FILE* fid,
Boolean isWideband, unsigned numChannels)
: AMRAudioSource(env, isWideband, numChannels),
fFid(fid) {
}
AMRAudioFileSource::~AMRAudioFileSource() {
CloseInputFile(fFid);
}
// The mapping from the "FT" field to frame size.
// Values of 65535 are invalid.
#define FT_INVALID 65535
static unsigned short frameSize[16] = {
12, 13, 15, 17,
19, 20, 26, 31,
5, FT_INVALID, FT_INVALID, FT_INVALID,
FT_INVALID, FT_INVALID, FT_INVALID, 0
};
static unsigned short frameSizeWideband[16] = {
17, 23, 32, 36,
40, 46, 50, 58,
60, 5, FT_INVALID, FT_INVALID,
FT_INVALID, FT_INVALID, 0, 0
};
void AMRAudioFileSource::doGetNextFrame() {
if (feof(fFid) || ferror(fFid)) {
handleClosure(this);
return;
}
// Begin by reading the 1-byte frame header (and checking it for validity)
while (1) {
if (fread(&fLastFrameHeader, 1, 1, fFid) < 1) {
handleClosure(this);
return;
}
if ((fLastFrameHeader&0x83) != 0) {
#ifdef DEBUG
fprintf(stderr, "Invalid frame header 0x%02x (padding bits (0x83) are not zero)\n", fLastFrameHeader);
#endif
} else {
unsigned char ft = (fLastFrameHeader&0x78)>>3;
fFrameSize = fIsWideband ? frameSizeWideband[ft] : frameSize[ft];
if (fFrameSize == FT_INVALID) {
#ifdef DEBUG
fprintf(stderr, "Invalid FT field %d (from frame header 0x%02x)\n",
ft, fLastFrameHeader);
#endif
} else {
// The frame header is OK
#ifdef DEBUG
fprintf(stderr, "Valid frame header 0x%02x -> ft %d -> frame size %d\n", fLastFrameHeader, ft, fFrameSize);
#endif
break;
}
}
}
// Next, read the frame-block into the buffer provided:
fFrameSize *= fNumChannels; // because multiple channels make up a frame-block
if (fFrameSize > fMaxSize) {
fNumTruncatedBytes = fFrameSize - fMaxSize;
fFrameSize = fMaxSize;
}
fFrameSize = fread(fTo, 1, fFrameSize, fFid);
// Set the 'presentation time':
if (fPresentationTime.tv_sec == 0 && fPresentationTime.tv_usec == 0) {
// This is the first frame, so use the current time:
gettimeofday(&fPresentationTime, NULL);
} else {
// Increment by the play time of the previous frame (20 ms)
unsigned uSeconds = fPresentationTime.tv_usec + 20000;
fPresentationTime.tv_sec += uSeconds/1000000;
fPresentationTime.tv_usec = uSeconds%1000000;
}
fDurationInMicroseconds = 20000; // each frame is 20 ms
// Switch to another task, and inform the reader that he has data:
nextTask() = envir().taskScheduler().scheduleDelayedTask(0,
(TaskFunc*)FramedSource::afterGetting, this);
}
|
