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• How to programmatically read an audio RTP stream using javacv and ffmpeg ?

  21 mai 2019, par Chris

  I am trying to read an audio RTP stream coming from ffmpeg in command line using javaCV. I create a DatagramSocket that listens to a specified port but can't get the audio frames.

  I have tried with different types of buffer to play the audio to my speakers but I am getting a lot of "Invalid return value 0 for stream protocol" error messages with no audio in my speakers.

  I am running the following command to stream an audio file:

  ffmpeg -re -i /some/file.wav -ar 44100 -f mulaw -f rtp rtp://127.0.0.1:7780

  And an excerpt of my code so far:

  public class FrameGrabber implements Runnable {

  private static final TimeUnit SECONDS = TimeUnit.SECONDS;
  private InetAddress ipAddress;
  private DatagramSocket serverSocket;
  
  public FrameGrabber(Integer port) throws UnknownHostException, SocketException {
      super();
  
      this.ipAddress = InetAddress.getByName("192.168.44.18");
      serverSocket = new DatagramSocket(port, ipAddress);
  
  }
  
  public AudioFormat getAudioFormat() {
      float sampleRate = 44100.0F;
      // 8000,11025,16000,22050,44100
      int sampleSizeInBits = 16;
      // 8,16
      int channels = 1;
      // 1,2
      boolean signed = true;
      // true,false
      boolean bigEndian = false;
      // true,false
      return new AudioFormat(sampleRate, sampleSizeInBits, channels, signed, bigEndian);
  }
  
  @Override
  public void run() {
  
  
      byte[] buffer = new byte[2048];
      DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
  
      DataInputStream dis = new DataInputStream(new ByteArrayInputStream(packet.getData(), packet.getOffset(), packet.getLength()));
  
  
      FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(dis);
      grabber.setFormat("mulaw");
      grabber.setSampleRate((int) getAudioFormat().getSampleRate());
      grabber.setAudioChannels(getAudioFormat().getChannels());
  
      SourceDataLine soundLine = null;
  
  
      try {
          grabber.start();
  
  
          if (grabber.getSampleRate() > 0 && grabber.getAudioChannels() > 0) {
  
              AudioFormat audioFormat = new AudioFormat(grabber.getSampleRate(), 16, grabber.getAudioChannels(), true, true);
  
              DataLine.Info info = new DataLine.Info(SourceDataLine.class, audioFormat);
              soundLine = (SourceDataLine) AudioSystem.getLine(info);
              soundLine.open(audioFormat);
  
              soundLine.start();
          }
  
          ExecutorService executor = Executors.newSingleThreadExecutor();
  
  
          while (true) {
  
              try {
                  serverSocket.receive(packet);
              } catch (IOException e) {
                  e.printStackTrace();
              }
  
              Frame frame = grabber.grab();
  
              //if (frame == null) break;
  
  
              if (frame != null && frame.samples != null) {
  
                  ShortBuffer channelSamplesFloatBuffer = (ShortBuffer) frame.samples[0];
                  channelSamplesFloatBuffer.rewind();
  
                  ByteBuffer outBuffer = ByteBuffer.allocate(channelSamplesFloatBuffer.capacity() * 2);
                  float[] samples = new float[channelSamplesFloatBuffer.capacity()];
  
                  for (int i = 0; i < channelSamplesFloatBuffer.capacity(); i++) {
                      short val = channelSamplesFloatBuffer.get(i);
                      outBuffer.putShort(val);
                  }
  
                  if (soundLine == null) return;
                  try {
                      SourceDataLine finalSoundLine = soundLine;
                      executor.submit(() -> {
                          finalSoundLine.write(outBuffer.array(), 0, outBuffer.capacity());
                          outBuffer.clear();
                      }).get();
                  } catch (InterruptedException interruptedException) {
                      Thread.currentThread().interrupt();
                  }
              }
  
          }
  
          /*
          executor.shutdownNow();
          executor.awaitTermination(1, SECONDS);
  
          if (soundLine != null) {
              soundLine.stop();
          }
  
          grabber.stop();
          grabber.release();*/
  
          } catch (ExecutionException ex) {
          System.out.println("ExecutionException");
          ex.printStackTrace();
      } catch (org.bytedeco.javacv.FrameGrabber.Exception ex) {
          System.out.println("FrameGrabberException");
          ex.printStackTrace();
      } catch (LineUnavailableException ex) {
          System.out.println("LineUnavailableException");
          ex.printStackTrace();
      }/* catch (InterruptedException e) {
          System.out.println("InterruptedException");
          e.printStackTrace();
      }*/
  
  
  }
  
  public static void main(String[] args) throws SocketException, UnknownHostException {
      Runnable apRunnable = new FrameGrabber(7780);
      Thread ap = new Thread(apRunnable);
      ap.start();
  }
  

  }

  At this stage, I am trying to play the audio file in my speakers but I am getting the following logs:

  Task :FrameGrabber.main() Invalid return value 0 for stream protocol Invalid return value 0 for stream protocol Input #0, mulaw, from 'java.io.DataInputStream@474e6cea': Duration: N/A, bitrate: 352 kb/s Stream #0:0: Audio: pcm_mulaw, 44100 Hz, 1 channels, s16, 352 kb/s Invalid return value 0 for stream protocol Invalid return value 0 for stream protocol Invalid return value 0 for stream protocol Invalid return value 0 for stream protocol ...

  What am I doing wrong?

  Thanks in advance!

• Advice on how to specify length of animated GPX video with ffmpeg/image2pipe

  21 mai 2019, par Chris Olin

  I'm working on a personal project involving an action camera that records GPS data alongside video from an image sensor. I found an open source projected on GitHub called 'trackanimation' that uses a colored marker to trace the GPX path on a OpenStreetMaps overlay, but it appears that the project has been abandoned. I'm trying to sync the trackanimation video to the image sensor video, but when I try using video editing software to slow the GPX video down to 1%, it still ends up being shorter than the image sensor video. I've tried messing with the baked in ffmpeg command in make_video(), but still can't get the output video to be as long as I want it to be.

  I started digging into the library source to see how the video was being created, tried tweaking a couple things to no avail.

  import trackanimation
  from trackanimation.animation import AnimationTrack
  
  gpx_file = "Videos/20190516 unity ride #2.mp4.gpx"
  gpx_track = trackanimation.read_track(gpx_file)
  
  fig = AnimationTrack(df_points=gpx_track, dpi=300, bg_map=True, map_transparency=0.7)
  fig.make_video(output_file="Videos/1-11trackanimationtest.mp4", framerate=30, linewidth=1.0)
  

      def make_video(self, linewidth=0.5, output_file='video', framerate=5):
          cmdstring = ('ffmpeg',
                       '-y',
                       '-loglevel', 'quiet',
                       '-framerate', str(framerate),
                       '-f', 'image2pipe',
                       '-i', 'pipe:',
                       '-r', '25',
                       '-s', '1920x1080',
                       '-pix_fmt', 'yuv420p',
                       output_file + '.mp4'
                       )
  

  I expect that I should be able to linearly "slow" the GPX video to a dynamic value based on the length of the video and the length I want it to be.

• I am building ffmpeg now, but I always get an error after executing make

  20 mai 2019, par user10818319

  Configure parameter /-- ./configure --prefix=/usr/workspace/android --disable-static --enable-shared --disable-ffplay --disable-ffprobe --disable-htmlpages --disable-manpages --disable-podpages --disable-txtpages --arch=arm --target-os=linux --cross-prefix=/usr/workspace/ndk/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/arm-linux-androideabi- --sysroot=/usr/workspace/ndk/platforms/android-21/arch-arm --extra-cflags="-Os -fpic $ADDI_CFLAGS" --extra-ldflags="$ADDI_LDFLAGS" --/

   make execution error 
  /--
  In file included from ./libavformat/internal.h:24:0,
                   from libavdevice/alldevices.c:23:
  /usr/workspace/ndk/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/lib/gcc/arm-linux-androideabi/4.9.x/include/stdint.h:9:26: fatal error: stdint.h: No such file or directory
   # include_next 
                            ^
  compilation terminated.
  make: *** [libavdevice/alldevices.o] Error 1
  
  --/
  

• automatic generate list ffmpeg trimming video files [duplicate]

  20 mai 2019, par Don

  This question already has an answer here:

  • How do you convert an entire directory with ffmpeg? 15 answers

  May I ask if there is an automatic way to input all the mp4 file names in the ffmpge code ? I have about 60 small video files that I need to trim, it is a pain if I have to keep entering individual file name. the mylist.txt generate only works with when concat

• Get motion vectors coordinates from next and previous frames durring transcoding in FFMPEG

  20 mai 2019, par Enock

  Can someone tells me how can I get values of motion vectors for next and previous frames in FFMPEG during transcoding, please? I can use MpegEncContext* s->mv_table to have values of motions vectors for current picture. But I need to get also MVs values for next and previous frame. How can I do ?