CameraSourceTimeLapse.h revision ceb388d6c03c38b96dc41c0ea4804b749aa077c4 
1/*
2 * Copyright (C) 2010 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#ifndef CAMERA_SOURCE_TIME_LAPSE_H_
18
19#define CAMERA_SOURCE_TIME_LAPSE_H_
20
21#include <pthread.h>
22
23#include <utils/RefBase.h>
24#include <utils/threads.h>
25#include <utils/String16.h>
26
27namespace android {
28
29class ICamera;
30class IMemory;
31class Camera;
32
33class CameraSourceTimeLapse : public CameraSource {
34public:
35    static CameraSourceTimeLapse *CreateFromCamera(
36        const sp<ICamera> &camera,
37        const sp<ICameraRecordingProxy> &proxy,
38        int32_t cameraId,
39        const String16& clientName,
40        uid_t clientUid,
41        Size videoSize,
42        int32_t videoFrameRate,
43        const sp<Surface>& surface,
44        int64_t timeBetweenTimeLapseFrameCaptureUs);
45
46    virtual ~CameraSourceTimeLapse();
47
48    // If the frame capture interval is large, read will block for a long time.
49    // Due to the way the mediaRecorder framework works, a stop() call from
50    // mediaRecorder waits until the read returns, causing a long wait for
51    // stop() to return. To avoid this, we can make read() return a copy of the
52    // last read frame with the same time stamp frequently. This keeps the
53    // read() call from blocking too long. Calling this function quickly
54    // captures another frame, keeps its copy, and enables this mode of read()
55    // returning quickly.
56    void startQuickReadReturns();
57
58private:
59    // size of the encoded video.
60    int32_t mVideoWidth;
61    int32_t mVideoHeight;
62
63    // Time between two frames in final video (1/frameRate)
64    int64_t mTimeBetweenTimeLapseVideoFramesUs;
65
66    // Real timestamp of the last encoded time lapse frame
67    int64_t mLastTimeLapseFrameRealTimestampUs;
68
69    // Variable set in dataCallbackTimestamp() to help skipCurrentFrame()
70    // to know if current frame needs to be skipped.
71    bool mSkipCurrentFrame;
72
73    // Lock for accessing mCameraIdle
74    Mutex mCameraIdleLock;
75
76    // Condition variable to wait on if camera is is not yet idle. Once the
77    // camera gets idle, this variable will be signalled.
78    Condition mCameraIdleCondition;
79
80    // True if camera is in preview mode and ready for takePicture().
81    // False after a call to takePicture() but before the final compressed
82    // data callback has been called and preview has been restarted.
83    volatile bool mCameraIdle;
84
85    // True if stop() is waiting for camera to get idle, i.e. for the last
86    // takePicture() to complete. This is needed so that dataCallbackTimestamp()
87    // can return immediately.
88    volatile bool mStopWaitingForIdleCamera;
89
90    // Lock for accessing quick stop variables.
91    Mutex mQuickStopLock;
92
93    // mQuickStop is set to true if we use quick read() returns, otherwise it is set
94    // to false. Once in this mode read() return a copy of the last read frame
95    // with the same time stamp. See startQuickReadReturns().
96    volatile bool mQuickStop;
97
98    // Forces the next frame passed to dataCallbackTimestamp() to be read
99    // as a time lapse frame. Used by startQuickReadReturns() so that the next
100    // frame wakes up any blocking read.
101    volatile bool mForceRead;
102
103    // Stores a copy of the MediaBuffer read in the last read() call after
104    // mQuickStop was true.
105    MediaBuffer* mLastReadBufferCopy;
106
107    // Status code for last read.
108    status_t mLastReadStatus;
109
110    CameraSourceTimeLapse(
111        const sp<ICamera> &camera,
112        const sp<ICameraRecordingProxy> &proxy,
113        int32_t cameraId,
114        const String16& clientName,
115        uid_t clientUid,
116        Size videoSize,
117        int32_t videoFrameRate,
118        const sp<Surface>& surface,
119        int64_t timeBetweenTimeLapseFrameCaptureUs);
120
121    // Wrapper over CameraSource::signalBufferReturned() to implement quick stop.
122    // It only handles the case when mLastReadBufferCopy is signalled. Otherwise
123    // it calls the base class' function.
124    virtual void signalBufferReturned(MediaBuffer* buffer);
125
126    // Wrapper over CameraSource::read() to implement quick stop.
127    virtual status_t read(MediaBuffer **buffer, const ReadOptions *options = NULL);
128
129    // mSkipCurrentFrame is set to true in dataCallbackTimestamp() if the current
130    // frame needs to be skipped and this function just returns the value of mSkipCurrentFrame.
131    virtual bool skipCurrentFrame(int64_t timestampUs);
132
133    // In the video camera case calls skipFrameAndModifyTimeStamp() to modify
134    // timestamp and set mSkipCurrentFrame.
135    // Then it calls the base CameraSource::dataCallbackTimestamp()
136    virtual void dataCallbackTimestamp(int64_t timestampUs, int32_t msgType,
137            const sp<IMemory> &data);
138
139    // Convenience function to fill mLastReadBufferCopy from the just read
140    // buffer.
141    void fillLastReadBufferCopy(MediaBuffer& sourceBuffer);
142
143    // If the passed in size (width x height) is a supported video/preview size,
144    // the function sets the camera's video/preview size to it and returns true.
145    // Otherwise returns false.
146    bool trySettingVideoSize(int32_t width, int32_t height);
147
148    // When video camera is used for time lapse capture, returns true
149    // until enough time has passed for the next time lapse frame. When
150    // the frame needs to be encoded, it returns false and also modifies
151    // the time stamp to be one frame time ahead of the last encoded
152    // frame's time stamp.
153    bool skipFrameAndModifyTimeStamp(int64_t *timestampUs);
154
155    // Wrapper to enter threadTimeLapseEntry()
156    static void *ThreadTimeLapseWrapper(void *me);
157
158    // Creates a copy of source_data into a new memory of final type MemoryBase.
159    sp<IMemory> createIMemoryCopy(const sp<IMemory> &source_data);
160
161    CameraSourceTimeLapse(const CameraSourceTimeLapse &);
162    CameraSourceTimeLapse &operator=(const CameraSourceTimeLapse &);
163};
164
165}  // namespace android
166
167#endif  // CAMERA_SOURCE_TIME_LAPSE_H_
168