I try running ffmpeg from Java, and for a couple of moments everything is working fine. I want ffmpeg to record my screen, and split the recording into small clips. The command is working fine from the terminal, but when I run it from Java I get at most 3 clips. Ffmpeg doesn’t write anything to the InputStream, so I have no idea what’s going wrong.

public static void execute(int frameRate, int width, int height, String windowTitle) {
      String[] args = new String[]{
              "ffmpeg",
              "-hide_banner",
              "-f", "gdigrab",
              "-thread_queue_size", "1024",
              "-rtbufsize", "256M",
              "-framerate", "60",
              "-offset_x", "0",
              "-offset_y", "0",
              "-video_size", "854x480",
              "-draw_mouse", "1",
              "-i", "title=Window Title* -something Like this",
              "-c:v", "libx264",
              "-r", "60",
              "-preset", "ultrafast",
              "-tune", "zerolatency",
              "-crf", "28",
              "-pix_fmt", "yuv420p",
              "-movflags", "+faststart",
              "-y",
              "-f", "segment",
              "-reset_timestamps", "1",
              "-segment_time", "1",
              "output%06d.mp4"
      };

      try {
          Process p = Runtime.getRuntime().exec(args);
          Thread thread = new Thread(() -> {
              String line;
              BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));

              System.out.println("TEST");
              try {
                  while ((line = input.readLine()) != null)
                      System.out.println(line);

                  System.out.println("Stopping with reading");
                  input.close();
              } catch (IOException e) {
                  e.printStackTrace();
              }
          });
          int exitCode = p.waitFor();
          thread.start();
          thread.join();
          if (exitCode != 0) {
              throw new RuntimeException("FFmpeg exited with code " + exitCode);
          }
      } catch (IOException | InterruptedException e) {
          throw new RuntimeException(e);
      }
  }

I’ve run the same command in the terminal. That worked fine. I ran the code above, but that resulted in ffmpeg stopping after 3 clips. It kept showing as working from the task manager. As said before, ffmpeg doesn’t write anything to the InputStream, even though it normally does write a lot in the terminal. The weird thing is, when I stop my Java program, but accidentally keep ffmpeg running, it suddenly does everything I wanted it to.