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• Layer black & white video over background so black pixels are transparent in FFMPEG

  4 février 2018, par Dan Weaver

  I’m trying to blend a video containing black and white animated text over a static background image. I can successfully blend them but no matter what blend mode I use I can’t get the effect I want.

  I’m looking for an effect similar to Photoshop’s ’Add’ blend mode where the color values of each pixel are added together. This results in no change where the top layer (video) has black pixels, effectively making the black background appear transparent.

  This is what I’m trying to achieve :
  

  ffmpeg -i text.mp4 -loop 1 -i image.jpg \
-filter_complex 'blend=all_mode=addition' -t 1 result.mp4

  I tried all the modes of the blend filter but none of them produce this effect. I thought Addition would be the one to work but the resulting video has a pink tint. Maybe there is some mismatch between color channels ?

  How can I get the result I’m looking for ?

• SDL/ffmpeg on iOS showing only blank or white screen

  3 avril 2018, par Law Gimenez

  I am following this ffmpeg/SDL tutorial using Swift and using the URL path as let urlPath = "rtsp://184.72.239.149/vod/mp4:BigBuckBunny_175k.mov" but it is only showing white or blank and it does not show anything. I want to show a window as what other tutorials say.

  I logged all the flow and there is no error. I have very little experience on SDL, let me know if some part of the code is not working.

• ffmpeg command not working with white space of directory path in Android

  13 avril 2017, par Sakib Syed

  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
  
      {
  
  
  
          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.