Add framework support for camcorder zoom.

The purpose of ICameraRecordingProxy and ICameraRecordingProxyListener is to
allow applications using the camera during recording.

Camera service allows only one client at a time. Since camcorder application
needs to own the camera to do things like zoom, the media recorder cannot
access the camera directly during recording. So ICameraRecordingProxy is a proxy
of ICamera, which allows the media recorder to start/stop the recording and
release recording frames. ICameraRecordingProxyListener is an interface that
allows the recorder to receive video frames during recording.

ICameraRecordingProxy
  startRecording()
  stopRecording()
  releaseRecordingFrame()

ICameraRecordingProxyListener
  dataCallbackTimestamp()

The camcorder app opens the camera and starts the preview. The app passes
ICamera and ICameraRecordingProxy to the media recorder by
MediaRecorder::setCamera(). The recorder uses ICamera to setup the camera in
MediaRecorder::start(). After setup, the recorder disconnects from camera
service. The recorder calls ICameraRecordingProxy::startRecording() and
passes a ICameraRecordingProxyListener to the app. The app connects back to
camera service and starts the recording. The app owns the camera and can do
things like zoom. The media recorder receives the video frames from the
listener and releases them by ICameraRecordingProxy::releaseRecordingFrame.
The recorder calls ICameraRecordingProxy::stopRecording() to stop the
recording.

The call sequences are as follows:
1. The app: Camera.unlock().
2. The app: MediaRecorder.setCamera().
3. Start recording
   (1) The app: MediaRecorder.start().
   (2) The recorder: ICamera.unlock() and ICamera.disconnect().
   (3) The recorder: ICameraRecordingProxy.startRecording().
   (4) The app: ICamera.reconnect().
   (5) The app: ICamera.startRecording().
4. During recording
   (1) The recorder: receive frames from ICameraRecordingProxyListener.dataCallbackTimestamp()
   (2) The recorder: release frames by ICameraRecordingProxy.releaseRecordingFrame().
5. Stop recording
   (1) The app: MediaRecorder.stop()
   (2) The recorder: ICameraRecordingProxy.stopRecording().
   (3) The app: ICamera.stopRecording().

bug:2644213

Change-Id: I15269397defc25cbbcae16abc071c8349c123122

1 files changed, 56 insertions, 32 deletions

diff --git a/media/libstagefright/CameraSource.cpp b/media/libstagefright/CameraSource.cpp
index 61bb2a8..bdffce9 100644
--- a/media/libstagefright/CameraSource.cpp
+++ b/media/libstagefright/CameraSource.cpp
@@ -115,19 +115,20 @@ CameraSource *CameraSource::Create() {
     size.height = -1;
 
     sp<ICamera> camera;
-    return new CameraSource(camera, 0, size, -1, NULL, false);
+    return new CameraSource(camera, NULL, 0, size, -1, NULL, false);
 }
 
 // static
 CameraSource *CameraSource::CreateFromCamera(
     const sp<ICamera>& camera,
+    const sp<ICameraRecordingProxy>& proxy,
     int32_t cameraId,
     Size videoSize,
     int32_t frameRate,
     const sp<Surface>& surface,
     bool storeMetaDataInVideoBuffers) {
 
-    CameraSource *source = new CameraSource(camera, cameraId,
+    CameraSource *source = new CameraSource(camera, proxy, cameraId,
                     videoSize, frameRate, surface,
                     storeMetaDataInVideoBuffers);
     return source;
@@ -135,6 +136,7 @@ CameraSource *CameraSource::CreateFromCamera(
 
 CameraSource::CameraSource(
     const sp<ICamera>& camera,
+    const sp<ICameraRecordingProxy>& proxy,
     int32_t cameraId,
     Size videoSize,
     int32_t frameRate,
@@ -153,11 +155,10 @@ CameraSource::CameraSource(
       mNumGlitches(0),
       mGlitchDurationThresholdUs(200000),
       mCollectStats(false) {
-
     mVideoSize.width  = -1;
     mVideoSize.height = -1;
 
-    mInitCheck = init(camera, cameraId,
+    mInitCheck = init(camera, proxy, cameraId,
                     videoSize, frameRate,
                     storeMetaDataInVideoBuffers);
 }
@@ -167,24 +168,32 @@ status_t CameraSource::initCheck() const {
 }
 
 status_t CameraSource::isCameraAvailable(
-    const sp<ICamera>& camera, int32_t cameraId) {
+    const sp<ICamera>& camera, const sp<ICameraRecordingProxy>& proxy,
+    int32_t cameraId) {
 
     if (camera == 0) {
         mCamera = Camera::connect(cameraId);
+        if (mCamera == 0) return -EBUSY;
+        // If proxy is not passed in by applications, still use the proxy of
+        // our own Camera to simplify the code.
+        mCameraRecordingProxy = mCamera->getRecordingProxy();
         mCameraFlags &= ~FLAGS_HOT_CAMERA;
     } else {
+        // We get the proxy from Camera, not ICamera. We need to get the proxy
+        // to the remote Camera owned by the application. Here mCamera is a
+        // local Camera object created by us. We cannot use the proxy from
+        // mCamera here.
         mCamera = Camera::create(camera);
+        if (mCamera == 0) return -EBUSY;
+        mCameraRecordingProxy = proxy;
         mCameraFlags |= FLAGS_HOT_CAMERA;
     }
 
-    // Is camera available?
-    if (mCamera == 0) {
-        LOGE("Camera connection could not be established.");
-        return -EBUSY;
-    }
-    if (!(mCameraFlags & FLAGS_HOT_CAMERA)) {
-        mCamera->lock();
-    }
+    mCamera->lock();
+    mDeathNotifier = new DeathNotifier();
+    // isBinderAlive needs linkToDeath to work.
+    mCameraRecordingProxy->asBinder()->linkToDeath(mDeathNotifier);
+
     return OK;
 }
 
@@ -447,6 +456,7 @@ status_t CameraSource::checkFrameRate(
  */
 status_t CameraSource::init(
         const sp<ICamera>& camera,
+        const sp<ICameraRecordingProxy>& proxy,
         int32_t cameraId,
         Size videoSize,
         int32_t frameRate,
@@ -455,7 +465,8 @@ status_t CameraSource::init(
     status_t err = OK;
     int64_t token = IPCThreadState::self()->clearCallingIdentity();
 
-    if ((err  = isCameraAvailable(camera, cameraId)) != OK) {
+    if ((err = isCameraAvailable(camera, proxy, cameraId)) != OK) {
+        LOGE("Camera connection could not be established.");
         return err;
     }
     CameraParameters params(mCamera->getParameters());
@@ -521,8 +532,14 @@ CameraSource::~CameraSource() {
 }
 
 void CameraSource::startCameraRecording() {
-    CHECK_EQ(OK, mCamera->startRecording());
-    CHECK(mCamera->recordingEnabled());
+    // Reset the identity to the current thread because media server owns the
+    // camera and recording is started by the applications. The applications
+    // will connect to the camera in ICameraRecordingProxy::startRecording.
+    int64_t token = IPCThreadState::self()->clearCallingIdentity();
+    mCamera->unlock();
+    mCamera.clear();
+    IPCThreadState::self()->restoreCallingIdentity(token);
+    CHECK_EQ(OK, mCameraRecordingProxy->startRecording(new ProxyListener(this)));
 }
 
 status_t CameraSource::start(MetaData *meta) {
@@ -544,20 +561,14 @@ status_t CameraSource::start(MetaData *meta) {
         mStartTimeUs = startTimeUs;
     }
 
-    // Call setListener first before calling startCameraRecording()
-    // to avoid recording frames being dropped.
-    int64_t token = IPCThreadState::self()->clearCallingIdentity();
-    mCamera->setListener(new CameraSourceListener(this));
     startCameraRecording();
-    IPCThreadState::self()->restoreCallingIdentity(token);
 
     mStarted = true;
     return OK;
 }
 
 void CameraSource::stopCameraRecording() {
-    mCamera->setListener(NULL);
-    mCamera->stopRecording();
+    mCameraRecordingProxy->stopRecording();
 }
 
 void CameraSource::releaseCamera() {
@@ -566,9 +577,9 @@ void CameraSource::releaseCamera() {
         LOGV("Camera was cold when we started, stopping preview");
         mCamera->stopPreview();
     }
-    mCamera->unlock();
     mCamera.clear();
-    mCamera = 0;
+    mCameraRecordingProxy->asBinder()->unlinkToDeath(mDeathNotifier);
+    mCameraRecordingProxy.clear();
     mCameraFlags = 0;
 }
 
@@ -578,7 +589,6 @@ status_t CameraSource::stop() {
     mStarted = false;
     mFrameAvailableCondition.signal();
 
-    int64_t token = IPCThreadState::self()->clearCallingIdentity();
     releaseQueuedFrames();
     while (!mFramesBeingEncoded.empty()) {
         if (NO_ERROR !=
@@ -589,7 +599,6 @@ status_t CameraSource::stop() {
     }
     stopCameraRecording();
     releaseCamera();
-    IPCThreadState::self()->restoreCallingIdentity(token);
 
     if (mCollectStats) {
         LOGI("Frames received/encoded/dropped: %d/%d/%d in %lld us",
@@ -607,8 +616,8 @@ status_t CameraSource::stop() {
 }
 
 void CameraSource::releaseRecordingFrame(const sp<IMemory>& frame) {
-    if (mCamera != NULL) {
-        mCamera->releaseRecordingFrame(frame);
+    if (mCameraRecordingProxy != NULL) {
+        mCameraRecordingProxy->releaseRecordingFrame(frame);
     }
 }
 
@@ -627,9 +636,7 @@ sp<MetaData> CameraSource::getFormat() {
 }
 
 void CameraSource::releaseOneRecordingFrame(const sp<IMemory>& frame) {
-    int64_t token = IPCThreadState::self()->clearCallingIdentity();
     releaseRecordingFrame(frame);
-    IPCThreadState::self()->restoreCallingIdentity(token);
 }
 
 void CameraSource::signalBufferReturned(MediaBuffer *buffer) {
@@ -669,7 +676,11 @@ status_t CameraSource::read(
         Mutex::Autolock autoLock(mLock);
         while (mStarted && mFramesReceived.empty()) {
             if (NO_ERROR !=
-                mFrameAvailableCondition.waitRelative(mLock, 3000000000LL)) {
+                mFrameAvailableCondition.waitRelative(mLock, 1000000000LL)) {
+                if (!mCameraRecordingProxy->asBinder()->isBinderAlive()) {
+                    LOGW("camera recording proxy is gone");
+                    return ERROR_END_OF_STREAM;
+                }
                 LOGW("Timed out waiting for incoming camera video frames: %lld us",
                     mLastFrameTimestampUs);
             }
@@ -745,4 +756,17 @@ bool CameraSource::isMetaDataStoredInVideoBuffers() const {
     return mIsMetaDataStoredInVideoBuffers;
 }
 
+CameraSource::ProxyListener::ProxyListener(const sp<CameraSource>& source) {
+    mSource = source;
+}
+
+void CameraSource::ProxyListener::dataCallbackTimestamp(
+        nsecs_t timestamp, int32_t msgType, const sp<IMemory>& dataPtr) {
+    mSource->dataCallbackTimestamp(timestamp / 1000, msgType, dataPtr);
+}
+
+void CameraSource::DeathNotifier::binderDied(const wp<IBinder>& who) {
+    LOGI("Camera recording proxy died");
+}
+
 }  // namespace android