cv2.VideoWritter not working

[fahad-humanoid-robots-1998]

I am facing the problem in writing the file:
> I have check all things like checking the rect , frame
> nothing of them is empty or false
> I am getting the processed frame MAT
> What I am facing is that the file does not save and there is no error or anything... Please guide me about this...
> I have read your other Issues like #303 and #143 but I don't have much knowledge about FFmpeg write now. So please
make me clear according to my scenario...
> Here is some Code to make it more clear...

    fourcc = cv2.VideoWriter_fourcc(*'MP4V')

    cap = cv2.VideoCapture(filename)
    flag = 1
    if (cap.isOpened() == False):
        print("Error opening video stream or file")
    exit_key = ord('q')
    while (cap.isOpened()):
        ret, frame = cap.read()
        if flag:
            height, width, _ = frame.shape
            out = cv2.VideoWriter(output+output_name, fourcc, 20.0, (2*width, height)) 
            flag = 0
        if ret:
            print('Video is processing..', end='\r')
            full_image = np.concatenate((frame, matte), axis=1)
            full_image = np.uint8(cv2.resize(full_image, (2*width, height), cv2.INTER_AREA))
            out.write(full_image)


  > I am reading files and want to save files into the internal storage what I have done for that is:


                --> This location is for the new processed file:
                                 path = join(os.environ["HOME"], path)  // path is suppose "output/"
                                 os.makedirs(path, exist_ok=True)
                                 if not path.endswith('/'):
                                 path += '/'
                                 return path


                 --> From Java Writing a file to Internal Storage:
                                  Uri data = null;
                                  if (result.getData() != null) {
                                      data = result.getData().getData();
                                      try {
                                          b = new byte[getContentResolver().openInputStream(data).available()];
                                          getContentResolver().openInputStream(data).read(b,0,b.length);
                                          String myFilePath = getFilesDir() + "/" + "fahad.mp4";
                                          File myFile = new File(myFilePath);
                                          FileOutputStream fos = new FileOutputStream(myFile);
                                          fos.write(b);
                                          fos.close();
                                      } catch (IOException e) {
                                          e.printStackTrace();
                                      }

[mhsmith]

As it says in #140, our builds of OpenCV don't support either reading or writing video files.

There's an example at #435 (comment) of using mobile-ffmpeg to convert the input video to PNG files, which you can then load and save individually in OpenCV. I'm not very familiar wth FFmpeg, but I guess there's probably a way of converting a sequence of PNG files back into a video, so that should solve your problem.

[fahad-humanoid-robots-1998]

Will FFmpeg be supported in future..?

[mhsmith]

It won't be supported directly in the near future, but you can use mobile-ffmpeg as a workaround, like I said.