Fix preview lag after stopping video recording

app/src/main/java/com/googleresearch/capturesync/ImageMetadataSynchronizer.java

@@ -396,6 +396,8 @@ public void onCaptureSequenceCompleted(@NonNull CameraCaptureSession session, in
             if (context.getLastVideoSeqId() != null && sequenceId == context.getLastVideoSeqId() && context.getLogger() != null) {
               context.getMediaRecorder().stop();
 
+              context.stopVideoPostPrepare();
+
               if (context.isVideoRecording()) {
                 context.setVideoRecording(false);
               } else {

app/src/main/java/com/googleresearch/capturesync/MainActivity.java

@@ -215,7 +215,7 @@ public void surfaceDestroyed(SurfaceHolder holder) {
     private PhaseAlignController phaseAlignController;
     private int numCaptures;
     private Toast latestToast;
-    private Surface surface;
+    private Surface recorderSurface;
 
 
     @Override
@@ -595,7 +595,7 @@ private PhaseConfig loadPhaseConfigFile() throws JSONException {
     private void closeCamera() {
         stopPreview();
         captureSession = null;
-        surface.release();
+        recorderSurface.release();
         if (cameraController != null) {
             cameraController.close();
             cameraController = null;
@@ -869,7 +869,7 @@ private void configureCaptureSession() {
         // MROB. Added MediaRecorder surface
         try {
             createRecorderSurface();
-            outputSurfaces.add(surface);
+            outputSurfaces.add(recorderSurface);
         } catch (IOException e) {
             e.printStackTrace();
         }
@@ -960,9 +960,9 @@ private String getOutputMediaFilePath() throws IOException {
     }
 
     private void createRecorderSurface() throws IOException {
-        surface = MediaCodec.createPersistentInputSurface();
+        recorderSurface = MediaCodec.createPersistentInputSurface();
 
-        MediaRecorder recorder = setUpMediaRecorder(surface, false);
+        MediaRecorder recorder = setUpMediaRecorder(recorderSurface, false);
         recorder.prepare();
         recorder.release();
         deleteUnusedVideo();
@@ -1015,7 +1015,7 @@ public void startVideo(boolean wantAutoExp) {
 
         isVideoRecording = true;
         try {
-            mediaRecorder = setUpMediaRecorder(surface);
+            mediaRecorder = setUpMediaRecorder(recorderSurface);
             String filename = lastTimeStamp + ".csv";
             // Creates frame timestamps logger
             try {
@@ -1024,12 +1024,12 @@ public void startVideo(boolean wantAutoExp) {
                 e.printStackTrace();
             }
             mediaRecorder.prepare();
-            Log.d(TAG, "MediaRecorder surface " + surface);
+            Log.d(TAG, "MediaRecorder surface " + recorderSurface);
             CaptureRequest.Builder previewRequestBuilder =
                     cameraController
                             .getRequestFactory()
                             .makeVideo(
-                                    surface,
+                                    recorderSurface,
                                     viewfinderSurface,
                                     cameraController.getOutputSurfaces(),
                                     currentSensorExposureTimeNs,
@@ -1054,7 +1054,18 @@ public void stopVideo() {
         // Switch to preview again
 
         Toast.makeText(this, "Stopped recording video", Toast.LENGTH_LONG).show();
-        startPreview();
+        try {
+            captureSession.stopRepeating();
+            captureSession.close();
+        } catch (CameraAccessException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public void stopVideoPostPrepare() {
+        mediaRecorder.reset();
+        recorderSurface.release();
+        configureCaptureSession();
     }
 
     private void stopPreview() {