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
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
|
/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program 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 General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include "sound/timestamp.h"
#include "common/algorithm.h"
namespace Audio {
Timestamp::Timestamp(uint ms, uint fr) {
assert(fr > 0);
_secs = ms / 1000;
_framerateFactor = 1000 / Common::gcd<uint>(1000, fr);
_framerate = fr * _framerateFactor;
// Note that _framerate is always divisible by 1000.
_numFrames = (ms % 1000) * (_framerate / 1000);
}
Timestamp::Timestamp(uint s, uint frames, uint fr) {
assert(fr > 0);
_secs = s;
_framerateFactor = 1000 / Common::gcd<uint>(1000, fr);
_framerate = fr * _framerateFactor;
_numFrames = frames * _framerateFactor;
normalize();
}
Timestamp Timestamp::convertToFramerate(uint newFramerate) const {
Timestamp ts(*this);
if (ts.framerate() != newFramerate) {
ts._framerateFactor = 1000 / Common::gcd<uint>(1000, newFramerate);
ts._framerate = newFramerate * ts._framerateFactor;
const uint g = Common::gcd(_framerate, ts._framerate);
const uint p = _framerate / g;
const uint q = ts._framerate / g;
// Convert the frame offset to the new framerate.
// We round to the nearest (as opposed to always
// rounding down), to minimize rounding errors during
// round trip conversions.
ts._numFrames = (ts._numFrames * q + p/2) / p;
ts.normalize();
}
return ts;
}
void Timestamp::normalize() {
// Convert negative _numFrames values to positive ones by adjusting _secs
if (_numFrames < 0) {
int secsub = 1 + (-_numFrames / _framerate);
_numFrames += _framerate * secsub;
_secs -= secsub;
}
// Wrap around if necessary
_secs += (_numFrames / _framerate);
_numFrames %= _framerate;
}
bool Timestamp::operator==(const Timestamp &ts) const {
return cmp(ts) == 0;
}
bool Timestamp::operator!=(const Timestamp &ts) const {
return cmp(ts) != 0;
}
bool Timestamp::operator<(const Timestamp &ts) const {
return cmp(ts) < 0;
}
bool Timestamp::operator<=(const Timestamp &ts) const {
return cmp(ts) <= 0;
}
bool Timestamp::operator>(const Timestamp &ts) const {
return cmp(ts) > 0;
}
bool Timestamp::operator>=(const Timestamp &ts) const {
return cmp(ts) >= 0;
}
int Timestamp::cmp(const Timestamp &ts) const {
int delta = _secs - ts._secs;
if (!delta) {
const uint g = Common::gcd(_framerate, ts._framerate);
const uint p = _framerate / g;
const uint q = ts._framerate / g;
delta = (_numFrames * q - ts._numFrames * p);
}
return delta;
}
Timestamp Timestamp::addFrames(int frames) const {
Timestamp ts(*this);
// The frames are given in the original framerate, so we have to
// adjust by _framerateFactor accordingly.
ts._numFrames += frames * _framerateFactor;
ts.normalize();
return ts;
}
Timestamp Timestamp::addMsecs(int ms) const {
Timestamp ts(*this);
ts._secs += ms / 1000;
// Add the remaining frames. Note that _framerate is always divisible by 1000.
ts._numFrames += (ms % 1000) * (ts._framerate / 1000);
ts.normalize();
return ts;
}
void Timestamp::addIntern(const Timestamp &ts) {
assert(_framerate == ts._framerate);
_secs += ts._secs;
_numFrames += ts._numFrames;
normalize();
}
Timestamp Timestamp::operator-() const {
Timestamp result(*this);
result._secs = -_secs;
result._numFrames = -_numFrames;
result.normalize();
return result;
}
Timestamp Timestamp::operator+(const Timestamp &ts) const {
Timestamp result(*this);
result.addIntern(ts);
return result;
}
Timestamp Timestamp::operator-(const Timestamp &ts) const {
Timestamp result(*this);
result.addIntern(-ts);
return result;
}
int Timestamp::frameDiff(const Timestamp &ts) const {
int delta = 0;
if (_secs != ts._secs)
delta = (_secs - ts._secs) * _framerate;
delta += _numFrames;
if (_framerate == ts._framerate) {
delta -= ts._numFrames;
} else {
// We need to multiply by the quotient of the two framerates.
// We cancel the GCD in this fraction to reduce the risk of
// overflows.
const uint g = Common::gcd(_framerate, ts._framerate);
const uint p = _framerate / g;
const uint q = ts._framerate / g;
delta -= ((long)ts._numFrames * p + q/2) / (long)q;
}
return delta / (int)_framerateFactor;
}
int Timestamp::msecsDiff(const Timestamp &ts) const {
return msecs() - ts.msecs();
}
int Timestamp::msecs() const {
// Note that _framerate is always divisible by 1000.
return _secs * 1000 + _numFrames / (_framerate / 1000);
}
} // End of namespace Audio
|
