I am working with FFMPEG library in which I want to rotate video using this library which works fine if I am file path has no any white space. But in my case I have white space of video directory (you can see full path in String commandStr onPreExecute() method of asynctask) path then it is not working at all. I have also seen same question like this and some more but not get any idea how to resolved it properly. Below is my code of MainActivity.class
    public class MainActivity extends AppCompatActivity implements View.OnClickListener{
    String workFolder = null;
    String demoVideoFolder = null;
    String vkLogPath = null;
    private boolean commandValidationFailedFlag = false;
    private Button btnRun;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        GeneralUtils.checkForPermissionsMAndAbove(MainActivity.this, true);
        setIds();
        setListner();
        demoVideoFolder = Environment.getExternalStorageDirectory().getAbsolutePath() + "/videokit/";
        Log.i(Prefs.TAG, getString(R.string.app_name) + " version: " + GeneralUtils.getVersionName(getApplicationContext()) );
        workFolder = getApplicationContext().getFilesDir().getAbsolutePath() + "/";
        vkLogPath = workFolder + "vk.log";
        GeneralUtils.copyLicenseFromAssetsToSDIfNeeded(this, workFolder);
        GeneralUtils.copyDemoVideoFromAssetsToSDIfNeeded(this, demoVideoFolder);
        int rc = GeneralUtils.isLicenseValid(getApplicationContext(), workFolder);
        Log.i(Prefs.TAG, "License check RC: " + rc);
    }
    private void setListner() {
        btnRun.setOnClickListener(this);
    }
    private void setIds() {
        try {
            btnRun =  (Button)findViewById(R.id.btnRun);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.btnRun:
                Log.i(Prefs.TAG, "run clicked.");
                if (GeneralUtils.checkIfFileExistAndNotEmpty(workFolder)) {
                    new TranscdingBackground(MainActivity.this).execute();
                }
                else {
                    Toast.makeText(getApplicationContext(), workFolder + " not found", Toast.LENGTH_LONG).show();
                }
                break;
        }
    }
    public class TranscdingBackground extends AsyncTask<String, Integer, Integer>
    {
        ProgressDialog progressDialog;
        Activity _act;
        String commandStr;
        public TranscdingBackground (Activity act) {
            _act = act;
        }
        @Override
        protected void onPreExecute() {
//            commandStr = "ffmpeg -y -i /storage/emulated/0/WhatsApp/Media/in.mp4 -vf rotate=270*(PI/180) /sdcard/videokit/out.mp4";
            commandStr = "ffmpeg -y -i /storage/emulated/0/WhatsApp/Media/WhatsApp Video/in.mp4 -vf rotate=270*(PI/180) /sdcard/videokit/out.mp4";
            progressDialog = new ProgressDialog(_act);
            progressDialog.setMessage("FFmpeg4Android Transcoding in progress...");
            progressDialog.show();
        }
        protected Integer doInBackground(String... paths) {
            Log.i(Prefs.TAG, "doInBackground started...");
            // delete previous log
            boolean isDeleted = GeneralUtils.deleteFileUtil(workFolder + "/vk.log");
            Log.i(Prefs.TAG, "vk deleted: " + isDeleted);
            PowerManager powerManager = (PowerManager)_act.getSystemService(Activity.POWER_SERVICE);
            PowerManager.WakeLock wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "VK_LOCK");
            Log.d(Prefs.TAG, "Acquire wake lock");
            wakeLock.acquire();
            LoadJNI vk = new LoadJNI();
            try {
                vk.run(GeneralUtils.utilConvertToComplex(commandStr), workFolder, getApplicationContext());
                // copying vk.log (internal native log) to the videokit folder
                GeneralUtils.copyFileToFolder(vkLogPath, demoVideoFolder);
            } catch (CommandValidationException e) {
                Log.e(Prefs.TAG, "vk run exeption.", e);
                commandValidationFailedFlag = true;
            } catch (Throwable e) {
                Log.e(Prefs.TAG, "vk run exeption.", e);
            }
            finally {
                if (wakeLock.isHeld())
                    wakeLock.release();
                else{
                    Log.i(Prefs.TAG, "Wake lock is already released, doing nothing");
                }
            }
            Log.i(Prefs.TAG, "doInBackground finished");
            return Integer.valueOf(0);
        }
        protected void onProgressUpdate(Integer... progress) {
        }
        @Override
        protected void onCancelled() {
            Log.i(Prefs.TAG, "onCancelled");
            //progressDialog.dismiss();
            super.onCancelled();
        }
        @Override
        protected void onPostExecute(Integer result) {
            Log.i(Prefs.TAG, "onPostExecute");
            progressDialog.dismiss();
            super.onPostExecute(result);
            // finished Toast
            String rc = null;
            if (commandValidationFailedFlag) {
                rc = "Command Vaidation Failed";
            }
            else {
                rc = GeneralUtils.getReturnCodeFromLog(vkLogPath);
            }
            final String status = rc;
            MainActivity.this.runOnUiThread(new Runnable() {
                public void run() {
                    Toast.makeText(MainActivity.this, status, Toast.LENGTH_LONG).show();
                    if (status.equals("Transcoding Status: Failed")) {
                        Toast.makeText(MainActivity.this, "Check: " + vkLogPath + " for more information.", Toast.LENGTH_LONG).show();
                    }
                }
            });
        }
    }
}
Here onPreExecute() method I have given video file path.