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      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