How to change the output file of a mediarecorder without stopping the mediarecorder

Question

I have a requirement in my project, where video is being recorded and uploaded to the server, but since mobile networks are not reliable, at the beginning what I decided to do was every 30 secs

• stop the recorder

• reset the recorder state

• retrieve the file written to by the recorder and upload (multipart form data) it in a different thread.

• change the outfile of the recorder to a new file based on the hash of the current timestamp.

• repeat process every 30 secs

Doing this suits my needs perfectly as each of the 30sec video file sizes are not more than 1MB and upload happens smoothly.

But the problem I am facing is that every time the media recorder stops and starts again there is a delay of about 500ms, so the video that I receive at the server has these 500ms breaks every 30secs which is really bad for my current situation, so I was thinking if it would be possible to just change the file that the recorder is writing to on the fly?

Relevant code:

GenericCallback onTickListener = new GenericCallback() {
        @Override
        public void execute(Object data) {
            int timeElapsedInSecs = (int) data;
            if (timeElapsedInSecs % pingIntervalInSecs == 0) {
                new API(getActivity().getApplicationContext()).pingServer(objInterviewQuestion.getCurrentAccessToken(),
                        new NetworkCallback() {
                    @Override
                    public void execute(int response_code, Object result) {
                        // TODO: HANDLE callback
                    }
                });
            }
            if (timeElapsedInSecs % uploadIntervalInSecs == 0 && timeElapsedInSecs < maxTimeInSeconds) {
                if (timeElapsedInSecs / uploadIntervalInSecs >= 1) {
                    if(stopAndResetRecorder()) {
                        openConnectionToUploadQueue();
                        uploadQueue.add(
                                new InterviewAnswer(0,
                                        objInterviewQuestion.getQid(),
                                        objInterviewQuestion.getAvf(),
                                        objInterviewQuestion.getNext(),
                                        objInterviewQuestion.getCurrentAccessToken()));
                        objInterviewQuestion.setAvf(MiscHelpers.getOutputMediaFilePath());
                        initializeAndStartRecording();
                    }
                }
            }
        }
    };

here is initializeAndStartRecording() :

private boolean initializeAndStartRecording() {
        Log.i("INFO", "initializeAndStartRecording");
        if (mCamera != null) {
            try {

                mMediaRecorder = CameraHelpers.initializeRecorder(mCamera,
                        mCameraPreview,
                        desiredVideoWidth,
                        desiredVideoHeight);

                mMediaRecorder.setOutputFile(objInterviewQuestion.getAvf());
                mMediaRecorder.prepare();
                mMediaRecorder.start();
                img_recording.setVisibility(View.VISIBLE);

                is_recording = true;
                return true;
            } catch (Exception ex) {
                MiscHelpers.showMsg(getActivity(),
                        getString(R.string.err_cannot_start_recorder),
                        AppMsg.STYLE_ALERT);
                return false;
            }


        } else {
            MiscHelpers.showMsg(getActivity(), getString(R.string.err_camera_not_available),
                    AppMsg.STYLE_ALERT);
            return false;
        }
    }

Here is stopAndResetRecorder:

boolean stopAndResetRecorder() {
        boolean success = false;
        try {
            if (mMediaRecorder != null) {
                try {
                    //stop recording
                    mMediaRecorder.stop();
                    mMediaRecorder.reset();
                    mMediaRecorder.release();
                    mMediaRecorder = null;
                    Log.d("MediaRecorder", "Recorder Stopped");
                    success = true;
                } catch (Exception ex) {
                    if(ex != null && ex.getMessage()!=null && ex.getMessage().isEmpty()){
                        Crashlytics.log(Log.ERROR, "Failed to stop MediaRecorder", ex.getMessage());
                        Crashlytics.logException(ex);
                    }
                    success = false;
                } finally {
                    mMediaRecorder = null;
                    is_recording = false;
                    is_recording = false;
                }
            }
        } catch (Exception ex) {
            success = false;
        }
        Log.d("MediaRecorder", "Success = " + String.valueOf(success));
        return success;
    }

Answer 1

You can speed it up slightly by not calling the release() method and all of the rest of the destruction that you do in stopAndResetRecorder() (see the documentation for the MediaRecorder state machine). You also don't need to call both stop() and reset().

You could instead have an intermediate resetRecorder() function which just performed reset() then call initializeAndStartRecording(). When you finish all of your recording, you could then call stopRecorder() which would perform the destruction of your mMediaRecorder.

As I say, this will save you some time, but whether the extra overhead you currently have of destroying and re-initialising the MediaRecorder is a significant portion of the delay I don't know. Give that a try, and if it doesn't fix your problem, I'd be interested to know how much time it did/didn't save.