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• ProcessBuilder is not called when trying to start a process

  15 juin 2022, par xnok

  I am trying to understand more about the ffmpeg usage in JavaCV for android studio and for said task I am trying to use ProcessBuilder. I tried writting a simple program to debug the pb.start(); Although, I am not getting a response. What I did was to start a default/empty activity and pasted the following program :

  


  package com.example.myapplication;

import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;

import org.bytedeco.javacpp.Loader;

import android.os.Build;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {
    static final int cols = 192;
    static final int rows = 108;
    static final String ffmpeg = Loader.load(org.bytedeco.ffmpeg.ffmpeg.class);
    static final String rtmp_url = "test.flv";
    static final String[] command = {ffmpeg,
            "-y",
            "-f", "rawvideo",
            "-vcodec", "rawvideo",
            "-pix_fmt", "bgr24",
            "-s", (Integer.toString(cols) + "x" + Integer.toString(rows)),
            "-r", "10",
            "-i", "pipe:",
            "-c:v", "libx264",
            "-pix_fmt", "yuv420p",
            "-preset", "ultrafast",
            "-f", "flv",
            rtmp_url};
    @RequiresApi(api = Build.VERSION_CODES.O)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        new Thread(t1).start();

    }
    private static Runnable t1 = () -> {
        Log.e("TAG", "void OnCreate called successfully!");
        ProcessBuilder pb = new ProcessBuilder(command).redirectErrorStream(true);
        pb.redirectErrorStream(true);
        try {
            Process process = pb.start();
            BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            OutputStream writer = process.getOutputStream();
            Log.e("TAG", "Something good happened here");
        } catch (IOException e) {
            e.printStackTrace();
            Log.e("TAG", "Nothing good happened here");
        }
    };


}


  


  My current problem is that I can't seem to start properly the processBuilder process via pb.start() ;

  


  I get the following logs from the logcat panel :

  


  2022-06-14 17:24:46.328 13371-13371/com.example.myapplication E/TAG: void OnCreate called successfully!
2022-06-14 17:24:46.333 13371-13371/com.example.myapplication E/TAG: Nothing good happened here


  


  I'd like to understand why is it skipping the try/catch block and not starting the process ?

  


  EDIT : I made some changes as per @g00se's suggestions and I got the following stack trace from the code above :

  


  2022-06-15 00:32:26.700 29787-29787/? E/USNET: USNET: appName: com.example.myapplication
2022-06-15 00:32:29.328 29787-29828/com.example.myapplication E/TAG: void OnCreate called successfully!
2022-06-15 00:32:29.330 29787-29828/com.example.myapplication E/AndroidRuntime: FATAL EXCEPTION: Thread-4
    Process: com.example.myapplication, PID: 29787
    java.lang.NullPointerException
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1012)
        at com.example.myapplication.MainActivity.lambda$static$0(MainActivity.java:48)
        at com.example.myapplication.MainActivity$$ExternalSyntheticLambda0.run(Unknown Source:0)
        at java.lang.Thread.run(Thread.java:920)


  


• avformat/dhav : fix backward scanning for get_duration and optimize seeking

  21 mars, par Justin Ruggles

  avformat/dhav : fix backward scanning for get_duration and optimize seeking
  The backwards scanning done for incomplete final packets should not
  
  assume a specific alignment at the end of the file. Truncated files
  
  result in hundreds of thousands of seeks if the final packet does not
  
  fall on a specific byte boundary, which can be extremely slow.
  
  For example, with HTTP, each backwards seek results in a separate
  
  HTTP request.
  This changes the scanning to check for the end tag 1 byte at a time
  
  and buffers the last 1 MiB to avoid additional seek operations.
  Co-authored-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  
  Signed-off-by : Justin Ruggles <justinr@vimeo.com>
  
  Signed-off-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  

  • [DH] libavformat/dhav.c

• make fifo pipe in java(windows), write some data into it, let other process read the pipe

  9 novembre 2017, par vs93

  My objective is to create a named pipe(fifo) in windows(java), write some data(coming from camera) into that and invoke ffmpeg command to make mp4 from that data. But I suspect that it is not opening a fifo pipe, rather it is opening a file. How can I make it open a fifo pipe ?
  Here is the code :

  public void run () {
  
  String mp4Folder = "C://Users/user_2/Desktop/streamDestination";            // Where the MP4 is to be kept
  
  VFrame frame = null;
  
  int actualPipeValLen = 0;
  
  FileOutputStream requestStream = null;
  
  long lastProcessedTS = 0;
  
  final String FIFOPATH = "D://FIFO//";
  
  final String PIPE_NAME = FIFOPATH + "myfifo";
  
  final String MKFIFOCOMMAND = "mkfifo -m=rw " + PIPE_NAME;
  
  final String DELFIFOCOMMAND = "rm -r " + PIPE_NAME;
  
  String mp4FileName = mp4Folder + File.separator + "1.mp4";
  
  mp4FileName = mp4FileName.replace("\\", "/");
  
  long firstTimeStamp = 0;
  
  try {
  
      Runtime.getRuntime().exec(MKFIFOCOMMAND);
  
  } catch (IOException e1) {
  
      e1.printStackTrace();
  
  }
  
  if(firstTimeStamp == 0) {
  
      firstTimeStamp = frame.getTimestamp();
  
  }
  
  if((frame.getTimestamp() - firstTimeStamp) > (15 * 1000)) {
  
      if(requestStream != null) {
  
          requestStream.close();
  
          requestStream = null;
  
      }
  
      if(actualPipeValLen > 0) {
  
          String[] ffmpeg = new String[] {"ffmpeg", "-i", PIPE_NAME , "-vcodec", "copy", mp4FileName };
  
          Process ffmpegProcess = Runtime.getRuntime().exec(ffmpeg);
  
          actualPipeValLen = 0;
  
          firstTimeStamp = lastProcessedTS;
  
          Thread.sleep(2 * 1000);
  
          try {
  
              Runtime.getRuntime().exec(DELFIFOCOMMAND);
  
          } catch (IOException e1) {
  
              e1.printStackTrace();
  
          }
  
          System.exit(0);
  
      }
  
  } else {
  
      System.out.println("Writing into pipe : " + actualPipeValLen);
  
      if(requestStream == null) {
  
          requestStream = new  FileOutputStream(PIPE_NAME);
  
      }
  
      requestStream.write(frame.getFrame());
  
      actualPipeValLen += frame.getFrame().length;
  
      lastProcessedTS = frame.getTimestamp();
  
  }

  }