1 /*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 //#define LOG_NDEBUG 0
18 #define LOG_TAG "MediaClock"
19 #include <utils/Log.h>
20
21 #include <media/stagefright/MediaClock.h>
22
23 #include <media/stagefright/foundation/ADebug.h>
24 #include <media/stagefright/foundation/ALooper.h>
25
26 namespace android {
27
28 // Maximum allowed time backwards from anchor change.
29 // If larger than this threshold, it's treated as discontinuity.
30 static const int64_t kAnchorFluctuationAllowedUs = 10000ll;
31
MediaClock()32 MediaClock::MediaClock()
33 : mAnchorTimeMediaUs(-1),
34 mAnchorTimeRealUs(-1),
35 mMaxTimeMediaUs(INT64_MAX),
36 mStartingTimeMediaUs(-1),
37 mPlaybackRate(1.0) {
38 }
39
~MediaClock()40 MediaClock::~MediaClock() {
41 }
42
setStartingTimeMedia(int64_t startingTimeMediaUs)43 void MediaClock::setStartingTimeMedia(int64_t startingTimeMediaUs) {
44 Mutex::Autolock autoLock(mLock);
45 mStartingTimeMediaUs = startingTimeMediaUs;
46 }
47
clearAnchor()48 void MediaClock::clearAnchor() {
49 Mutex::Autolock autoLock(mLock);
50 mAnchorTimeMediaUs = -1;
51 mAnchorTimeRealUs = -1;
52 }
53
updateAnchor(int64_t anchorTimeMediaUs,int64_t anchorTimeRealUs,int64_t maxTimeMediaUs)54 void MediaClock::updateAnchor(
55 int64_t anchorTimeMediaUs,
56 int64_t anchorTimeRealUs,
57 int64_t maxTimeMediaUs) {
58 if (anchorTimeMediaUs < 0 || anchorTimeRealUs < 0) {
59 ALOGW("reject anchor time since it is negative.");
60 return;
61 }
62
63 Mutex::Autolock autoLock(mLock);
64 int64_t nowUs = ALooper::GetNowUs();
65 int64_t nowMediaUs =
66 anchorTimeMediaUs + (nowUs - anchorTimeRealUs) * (double)mPlaybackRate;
67 if (nowMediaUs < 0) {
68 ALOGW("reject anchor time since it leads to negative media time.");
69 return;
70 }
71
72 if (maxTimeMediaUs != -1) {
73 mMaxTimeMediaUs = maxTimeMediaUs;
74 }
75 if (mAnchorTimeRealUs != -1) {
76 int64_t oldNowMediaUs =
77 mAnchorTimeMediaUs + (nowUs - mAnchorTimeRealUs) * (double)mPlaybackRate;
78 if (nowMediaUs < oldNowMediaUs
79 && nowMediaUs > oldNowMediaUs - kAnchorFluctuationAllowedUs) {
80 return;
81 }
82 }
83 mAnchorTimeRealUs = nowUs;
84 mAnchorTimeMediaUs = nowMediaUs;
85 }
86
updateMaxTimeMedia(int64_t maxTimeMediaUs)87 void MediaClock::updateMaxTimeMedia(int64_t maxTimeMediaUs) {
88 Mutex::Autolock autoLock(mLock);
89 mMaxTimeMediaUs = maxTimeMediaUs;
90 }
91
setPlaybackRate(float rate)92 void MediaClock::setPlaybackRate(float rate) {
93 CHECK_GE(rate, 0.0);
94 Mutex::Autolock autoLock(mLock);
95 if (mAnchorTimeRealUs == -1) {
96 mPlaybackRate = rate;
97 return;
98 }
99
100 int64_t nowUs = ALooper::GetNowUs();
101 mAnchorTimeMediaUs += (nowUs - mAnchorTimeRealUs) * (double)mPlaybackRate;
102 if (mAnchorTimeMediaUs < 0) {
103 ALOGW("setRate: anchor time should not be negative, set to 0.");
104 mAnchorTimeMediaUs = 0;
105 }
106 mAnchorTimeRealUs = nowUs;
107 mPlaybackRate = rate;
108 }
109
getPlaybackRate() const110 float MediaClock::getPlaybackRate() const {
111 Mutex::Autolock autoLock(mLock);
112 return mPlaybackRate;
113 }
114
getMediaTime(int64_t realUs,int64_t * outMediaUs,bool allowPastMaxTime) const115 status_t MediaClock::getMediaTime(
116 int64_t realUs, int64_t *outMediaUs, bool allowPastMaxTime) const {
117 if (outMediaUs == NULL) {
118 return BAD_VALUE;
119 }
120
121 Mutex::Autolock autoLock(mLock);
122 return getMediaTime_l(realUs, outMediaUs, allowPastMaxTime);
123 }
124
getMediaTime_l(int64_t realUs,int64_t * outMediaUs,bool allowPastMaxTime) const125 status_t MediaClock::getMediaTime_l(
126 int64_t realUs, int64_t *outMediaUs, bool allowPastMaxTime) const {
127 if (mAnchorTimeRealUs == -1) {
128 return NO_INIT;
129 }
130
131 int64_t mediaUs = mAnchorTimeMediaUs
132 + (realUs - mAnchorTimeRealUs) * (double)mPlaybackRate;
133 if (mediaUs > mMaxTimeMediaUs && !allowPastMaxTime) {
134 mediaUs = mMaxTimeMediaUs;
135 }
136 if (mediaUs < mStartingTimeMediaUs) {
137 mediaUs = mStartingTimeMediaUs;
138 }
139 if (mediaUs < 0) {
140 mediaUs = 0;
141 }
142 *outMediaUs = mediaUs;
143 return OK;
144 }
145
getRealTimeFor(int64_t targetMediaUs,int64_t * outRealUs) const146 status_t MediaClock::getRealTimeFor(
147 int64_t targetMediaUs, int64_t *outRealUs) const {
148 if (outRealUs == NULL) {
149 return BAD_VALUE;
150 }
151
152 Mutex::Autolock autoLock(mLock);
153 if (mPlaybackRate == 0.0) {
154 return NO_INIT;
155 }
156
157 int64_t nowUs = ALooper::GetNowUs();
158 int64_t nowMediaUs;
159 status_t status =
160 getMediaTime_l(nowUs, &nowMediaUs, true /* allowPastMaxTime */);
161 if (status != OK) {
162 return status;
163 }
164 *outRealUs = (targetMediaUs - nowMediaUs) / (double)mPlaybackRate + nowUs;
165 return OK;
166 }
167
168 } // namespace android
169