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• FFMpeg transcoding for realtime videochat via UDP

  4 septembre 2018, par Lloyd Corfex

  My problem is that I can’t find settings matching my needs.
  I know there is a tradeoff between : Speed, Quality and Size.

  (I am using a wrapper, so I can’t tell you the exact ffmpeg string but it should be comprehensible.)

  Input is always a raw video (bitmaps provided by webcam).

  CustomInputArgs = string.Format(" -pix_fmt bgr24 -video_size {0}x{1}", bitmapSize.Width, bitmapSize.Height),
  
  CustomOutputArgs = string.Format(" -vf scale=-1:{0} -maxrate 3000k -bufsize 4500k -preset ultrafast -tune zerolatency -movflags faststart", scale)

  Format : H.264

  • Speed -> ok
  • Size -> ok
  • Quality -> Not okay - Result gets "blocky" / "pixelchaos"

  
  [https://www.pic-upload.de/view-35890878/HalloPixel.jpg.html
  ]

  Format : H.265 and AVI

  • Speed -> Way too slow

  Format : FLV

  • Results in only a black screen (even if i set one of the following to the encoder)
    [https://stackoverflow.com/a/12290903/10144526]

    CustomOutputArgs = " -pix_fmt yuv420p"

    CustomOutputArgs = " -pix_fmt yuyv422"

  • As long as i have any string in the encoder outputArgs i get the following error in ffmpeg : [flv @ 03c27e40] Packet mismatch 1239459658 55255 55450

  Format MJPEG

  • Quality -> Super
  • Speed -> Ok
  • Size -> Gigantic

  Format M4V

  • Quality -> Not good
  • Speed -> Ok
  • Size -> Ok

  Format MP4

  • Conversion failed

  Does anyone has an idea about good settings ? Or can advice me in a good direction ?

• How do I properly enable ffmpeg for matplotlib.animation ?

  9 novembre 2018, par spanishgum

  I have covered a lot of ground on stack so far trying to get ffmpeg going so I can make a timelapse video.

  I am on a CentOS 7 machine, running python3.7.0a0.

  python3
  
  >>> import numpy as np
  
  >>> np.__version__
  
  '1.12.0'
  
  >>> import matplotlib as mpl
  
  >>> mpl.__version__
  
  '2.0.0'
  
  >>> import mpl_toolkits.basemap as base
  
  >>> base.__version__
  
  '1.0.7'

  I found this github gist on installing ffmpeg. I used the chromium source, and installed without a prefix option (using the default).

  I have confirmed that ffmpeg is installed, although I don’t know anything about testing whether it works.

  which ffmpeg
  
  /usr/local/bin/ffmpeg
  
  
  
  ffmpeg -version
  
  ffmpeg version N-83533-gada281d Copyright (c) 2000-2017 the FFmpeg dev elopers
  
  built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-11
  
  configuration:
  
  libavutil      55. 47.100 / 55. 47.100
  
  libavcodec     57. 80.100 / 57. 80.100
  
  libavformat    57. 66.102 / 57. 66.102
  
  libavdevice    57.  2.100 / 57.  2.100
  
  libavfilter     6. 73.100 /  6. 73.100
  
  libswscale      4.  3.101 /  4.  3.101
  
  libswresample   2.  4.100 /  2.  4.100

  I tried to run a few sample examples I found online :

  [1] http://matplotlib.org/examples/animation/basic_example_writer.html

  [2] https://stackoverflow.com/a/23098090/3454650

  Everything works fine up until I try to save the animation file.

  [1]

   anim.save('basic_animation.mp4', writer = FFwriter, fps=30, extra_args=['-vcodec', 'libx264'])

  [2]

  im_ani.save('im.mp4', writer=writer)

  I found here that explictly setting the path to ffmpeg might be necessary so I added this to the top of the test scripts :

  plt.rcParams['animation.ffmpeg_path'] = '/usr/local/bin/ffmpeg'

  I tried a few more tweaks in the code but always get the same response, which I do not know how to begin deciphering :

  Traceback (most recent call last):
  
    File "testanim.py", line 27, in <module>
  
      writer.grab_frame()
  
    File "/usr/local/lib/python3.7/contextlib.py", line 100, in __exit__
  
      self.gen.throw(type, value, traceback)
  
    File "/usr/local/lib/python3.7/site-packages/matplotlib/animation.py", line 256, in saving
  
      self.finish()
  
    File "/usr/local/lib/python3.7/site-packages/matplotlib/animation.py", line 276, in finish
  
      self.cleanup()
  
    File "/usr/local/lib/python3.7/site-packages/matplotlib/animation.py", line 311, in cleanup
  
      out, err = self._proc.communicate()
  
    File "/usr/local/lib/python3.7/subprocess.py", line 836, in communicate
  
      stdout, stderr = self._communicate(input, endtime, timeout)
  
    File "/usr/local/lib/python3.7/subprocess.py", line 1474, in _communicate
  
      selector.register(self.stdout, selectors.EVENT_READ)
  
    File "/usr/local/lib/python3.7/selectors.py", line 351, in register
  
      key = super().register(fileobj, events, data)
  
    File "/usr/local/lib/python3.7/selectors.py", line 237, in register
  
      key = SelectorKey(fileobj, self._fileobj_lookup(fileobj), events, data)
  
    File "/usr/local/lib/python3.7/selectors.py", line 224, in _fileobj_lookup
  
      return _fileobj_to_fd(fileobj)
  
    File "/usr/local/lib/python3.7/selectors.py", line 39, in _fileobj_to_fd
  
      "{!r}".format(fileobj)) from None
  
  ValueError: Invalid file object: &lt;_io.BufferedReader name=6>
  
  </module>

  Is there something with my configuration that is malformed ? I searched google for this error for some time but never found anything relevant to animations / ffmpeg. Any help would be greatly appreciated.

  ---

  UPDATE :

  @LordNeckBeard pointed me here : https://trac.ffmpeg.org/wiki/CompilationGuide/Centos

  I ran into problems with installing the x264 encoding dependency. Some files in libavcodec/*.c (in the make output) were reporting undefined references to several functions. After a wild goose chase found this : https://mailman.videolan.org/pipermail/x264-devel/2015-February/010971.html

  To fix the x264 installation, I simply added some configure flags :

  ./configure --enable-static --enable-shared --extra-ldflags="-lswresample -llzma"

  ---

  UPDATE :

  So everything installed fine after fixing the libx264 problems. I went ahead and copied the ffmpeg binary from the ffmpeg_build folder into /usr/local/bin/ffmpeg.

  After running the script I was getting problems where ffmpeg could not find the libx264 shared object. I think I will have to recompile everything using different prefixes. My intuition tells me there are old files laying around after I have messed with everything, using some configuration that is broken.

  So I decided maybe I should just try to use NUX : http://linoxide.com/linux-how-to/install-ffmpeg-centos-7/
  I installed ffmpeg using the new rpm, but to no avail. I still was not able to run ffmpeg because of a missing shared object.

  Finally, instead of usiong files copied into my /usr/local/bin folder, I ran ffmpeg directly from the build bin directory. Turns out that this does work properly !

  So in essence, if I want to install ffmpeg system wide, I need to manually compile from sources again but using a nonlocal prefix.

• How to decrease the latency of the RTP streaming with ffmpeg in Android ?

  24 août 2018, par Douglas Lima Dantas

  I’m creating a App that do a RTP streaming. It uses a ParcelFileDescriptor pipe pair, where a MediaRecorder writes in the pipe while the ffmpeg receives the audio from the pipe and sends by RTP.

  In my desktop, using the same wifi router, I receive the RTP stream using ffplay, and it has a delay between 5s 10s.

  I tried capture audio using ffmpeg in Android, but itsn’t possible. I tried to use ffplay -fflags nobuffer, use MIC as source, change the encoder, etc.

  I need the lowest delay possible. How can I do it ?

  The code :

  public class MainActivity extends AppCompatActivity implements View.OnClickListener {
  
      MediaRecorder mediaRecorder;
  
      AudioRecord record;
  
      MediaPlayer mediaPlayer;
  
      ParcelFileDescriptor[] pipePair;
  
      ParcelFileDescriptor pipeRead;
  
      ParcelFileDescriptor pipeWrite;
  
      Process ffmpegProc;
  
      // Requesting permission to RECORD_AUDIO
  
      private boolean permissionsAccepted = false;
  
      private String [] permissions = {
  
              Manifest.permission.RECORD_AUDIO,
  
              Manifest.permission.INTERNET,
  
              Manifest.permission.ACCESS_NETWORK_STATE
  
      };
  
      private static final int REQUEST_PERMISSIONS = 200;
  
  
  
      @Override
  
      public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
  
          super.onRequestPermissionsResult(requestCode, permissions, grantResults);
  
          switch (requestCode){
  
              case REQUEST_PERMISSIONS:
  
                  permissionsAccepted  = grantResults[0] == PackageManager.PERMISSION_GRANTED;
  
                  break;
  
          }
  
          if (!permissionsAccepted ) finish();
  
  
  
      }
  
  
  
      @Override
  
      protected void onCreate(Bundle savedInstanceState) {
  
          super.onCreate(savedInstanceState);
  
          setContentView(R.layout.activity_main);
  
          ActivityCompat.requestPermissions(this, permissions, REQUEST_PERMISSIONS);
  
  
  
          TextView hello = (TextView) findViewById(R.id.hello);
  
          hello.setOnClickListener(new View.OnClickListener() {
  
              @Override
  
              public void onClick(View view) {
  
                  Toast.makeText(MainActivity.this, "Clicado",Toast.LENGTH_SHORT)
  
                          .show();
  
                  copiarFFMpeg();
  
  
  
              }
  
          });
  
  
  
      }
  
  
  
      private void executarFFMpeg(final String[] cmd, ParcelFileDescriptor read) {
  
  
  
          try {
  
              ffmpegProc = Runtime.getRuntime().exec(cmd);
  
          } catch (IOException e) {
  
              e.printStackTrace();
  
          }
  
  
  
          (new Thread(new Runnable() {
  
              @Override
  
              public void run() {
  
                  try {
  
                      InputStream inStream = ffmpegProc.getInputStream();
  
                      InputStreamReader sReader = new InputStreamReader(inStream);
  
                      BufferedReader bufferedReader = new BufferedReader(sReader);
  
                      String line;
  
                      while ((line = bufferedReader.readLine()) != null) {
  
                          Log.d("FFMPEG",line);
  
                      }
  
                  } catch (IOException e) {
  
                      e.printStackTrace();
  
                  }
  
              }
  
          })).start();
  
  
  
          (new Thread(new Runnable() {
  
              @Override
  
              public void run() {
  
                  byte[] buffer = new byte[8192];
  
                  int read = 0;
  
  
  
                  OutputStream ffmpegInput = ffmpegProc.getOutputStream();
  
                  FileInputStream reader = new FileInputStream(pipeRead.getFileDescriptor());
  
  
  
                  try {
  
  
  
                      while (true) {
  
  
  
                          if (reader.available()>0) {
  
                              read = reader.read(buffer);
  
                              ffmpegInput.write(buffer, 0, read);
  
                              ffmpegInput.flush();
  
                          } else {
  
                              Thread.sleep(10);
  
                          }
  
  
  
                      }
  
  
  
                  } catch (InterruptedException e) {
  
                      e.printStackTrace();
  
  
  
                  } catch (IOException e) {
  
                      e.printStackTrace();
  
  
  
                      onDestroy();
  
                  }
  
              }
  
          })).start();
  
  
  
          Log.d("FFMPEG","Executado");
  
      }
  
  
  
      private boolean estaExecutando(Process ffmpegProc) {
  
          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
  
              return ffmpegProc.isAlive();
  
          } else {
  
              try {
  
                  ffmpegProc.exitValue();
  
                  return false;
  
              } catch (Exception e) {
  
                  return true;
  
              }
  
          }
  
      }
  
  
  
      private void criarMediaRecorder() {
  
          if (pipeWrite != null) {
  
              try {
  
                  //ffplay.exe -protocol_whitelist rtp,file,udp ..\file.sdp
  
                  mediaRecorder = new MediaRecorder();
  
                  mediaRecorder.setAudioSource(MediaRecorder.AudioSource.VOICE_COMMUNICATION);
  
                  mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.AAC_ADTS);
  
                  mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
  
                  //mediaRecorder.setAudioChannels(2);
  
                  mediaRecorder.setOutputFile(pipeWrite.getFileDescriptor());
  
                  mediaRecorder.prepare();
  
                  mediaRecorder.start();
  
                  Log.d("MREC","MediaRecorder criado");
  
              } catch (Exception e) {
  
                  e.printStackTrace();
  
              }
  
          }
  
      }
  
  
  
      private void criarPipe() {
  
          try {
  
              pipePair =ParcelFileDescriptor.createPipe();
  
          } catch (IOException e) {
  
              Log.e("PIPE","Deu zica na criação do pipe");
  
              e.printStackTrace();
  
              finish();
  
          }
  
          pipeRead = new ParcelFileDescriptor(pipePair[0]);
  
          pipeWrite  = new ParcelFileDescriptor(pipePair[1]);
  
      }
  
  
  
      private void copiarFFMpeg() {
  
          FFmpeg ffmpeg = FFmpeg.getInstance(this);
  
          try {
  
              ffmpeg.loadBinary(new LoadBinaryResponseHandler() {
  
  
  
                  @Override
  
                  public void onStart() {
  
                      Log.d("FFMPEG","Iniciar cópia");
  
                  }
  
  
  
                  @Override
  
                  public void onFailure() {
  
                      Log.e("FFMPEG","Cópia falhou");
  
                  }
  
  
  
                  @Override
  
                  public void onSuccess() {
  
                      Log.d("FFMPEG","Cópiado com sucesso");
  
  
  
                      criarPipe();
  
                      //mediaRecorder.start();
  
                      File ffmpegBin = new File(getFilesDir().getAbsolutePath()+"/ffmpeg");
  
                      String[] cmd = new String[] {
  
                              ffmpegBin.getAbsolutePath(),
  
                              "-re",
  
                              "-thread_queue_size","4",
  
                              "-i","pipe:",
  
                              //"-c:a","libx264",
  
                              //"-preset","veryfast",
  
                              //"-tune","zerolatency",
  
                              "-f",
  
                              "rtp",
  
                              "rtp://192.168.0.33:1234"
  
                      };
  
  
  
                      executarFFMpeg(cmd, pipeRead);
  
  
  
                      criarMediaRecorder();
  
                  }
  
  
  
                  @Override
  
                  public void onFinish() {
  
                  }
  
              });
  
          } catch (FFmpegNotSupportedException e) {
  
              // Handle if FFmpeg is not supported by device
  
              Log.e("FFMPEG", "Não sou suportado :/");
  
          }
  
      }
  
  
  
      @Override
  
      protected void onDestroy() {
  
          super.onDestroy();
  
      }
  
  
  
      @Override
  
      public void onClick(View view) {
  
  
  
      }
  
  }

  The command :

  ffplay rtp://192.168.0.33:1234
  
  
  
  ffplay -fflags nobuffer rtp://192.168.0.33:1234