1 /*
2  * Copyright (C) 2011 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 ANDROID_HARDWARE_ICAMERA_RECORDING_PROXY_H
18 #define ANDROID_HARDWARE_ICAMERA_RECORDING_PROXY_H
19 
20 #include <binder/IInterface.h>
21 #include <cutils/native_handle.h>
22 #include <utils/RefBase.h>
23 
24 namespace android {
25 
26 class ICameraRecordingProxyListener;
27 class IMemory;
28 class Parcel;
29 
30 /*
31  * The purpose of ICameraRecordingProxy and ICameraRecordingProxyListener is to
32  * allow applications using the camera during recording.
33  *
34  * Camera service allows only one client at a time. Since camcorder application
35  * needs to own the camera to do things like zoom, the media recorder cannot
36  * access the camera directly during recording. So ICameraRecordingProxy is a
37  * proxy of ICamera, which allows the media recorder to start/stop the recording
38  * and release recording frames. ICameraRecordingProxyListener is an interface
39  * that allows the recorder to receive video frames during recording.
40  *
41  * ICameraRecordingProxy
42  *   startRecording()
43  *   stopRecording()
44  *   releaseRecordingFrame()
45  *
46  * ICameraRecordingProxyListener
47  *   dataCallbackTimestamp()
48 
49  * The camcorder app opens the camera and starts the preview. The app passes
50  * ICamera and ICameraRecordingProxy to the media recorder by
51  * MediaRecorder::setCamera(). The recorder uses ICamera to setup the camera in
52  * MediaRecorder::start(). After setup, the recorder disconnects from camera
53  * service. The recorder calls ICameraRecordingProxy::startRecording() and
54  * passes a ICameraRecordingProxyListener to the app. The app connects back to
55  * camera service and starts the recording. The app owns the camera and can do
56  * things like zoom. The media recorder receives the video frames from the
57  * listener and releases them by ICameraRecordingProxy::releaseRecordingFrame.
58  * The recorder calls ICameraRecordingProxy::stopRecording() to stop the
59  * recording.
60  *
61  * The call sequences are as follows:
62  * 1. The app: Camera.unlock().
63  * 2. The app: MediaRecorder.setCamera().
64  * 3. Start recording
65  *    (1) The app: MediaRecorder.start().
66  *    (2) The recorder: ICamera.unlock() and ICamera.disconnect().
67  *    (3) The recorder: ICameraRecordingProxy.startRecording().
68  *    (4) The app: ICamera.reconnect().
69  *    (5) The app: ICamera.startRecording().
70  * 4. During recording
71  *    (1) The recorder: receive frames from ICameraRecordingProxyListener.dataCallbackTimestamp()
72  *    (2) The recorder: release frames by ICameraRecordingProxy.releaseRecordingFrame().
73  * 5. Stop recording
74  *    (1) The app: MediaRecorder.stop()
75  *    (2) The recorder: ICameraRecordingProxy.stopRecording().
76  *    (3) The app: ICamera.stopRecording().
77  */
78 
79 class ICameraRecordingProxy: public IInterface
80 {
81 public:
82     DECLARE_META_INTERFACE(CameraRecordingProxy);
83 
84     virtual status_t        startRecording(const sp<ICameraRecordingProxyListener>& listener) = 0;
85     virtual void            stopRecording() = 0;
86     virtual void            releaseRecordingFrame(const sp<IMemory>& mem) = 0;
87     virtual void            releaseRecordingFrameHandle(native_handle_t *handle) = 0;
88 };
89 
90 // ----------------------------------------------------------------------------
91 
92 class BnCameraRecordingProxy: public BnInterface<ICameraRecordingProxy>
93 {
94 public:
95     virtual status_t    onTransact( uint32_t code,
96                                     const Parcel& data,
97                                     Parcel* reply,
98                                     uint32_t flags = 0);
99 };
100 
101 }; // namespace android
102 
103 #endif
104