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• Problems with timeout when there is no video source with RTP format in java openCV

  15 février 2019, par Javier Dalmau Fajardo

  I have problems with the timeout when there is no video source with RTP format.

  If I execute the code and there is no video, the program stays waiting in the grabber.Start () function all the time.

  FFmpegFrameGrabber grabber;
  
  try{
  
      Frame img;        
  
      grabber = new FFmpegFrameGrabber("rtp://" + ip + ":1234");
  
      grabber.setOption("stimeout", String.valueOf(5*1000000));
  
      grabber.Start ();
  
      img = grabber.grab();
  
      Java2DFrameConverter converter = new Java2DFrameConverter();
  
  BufferedImage bufferedImag;
  
  bufferedImag = converter.convert(img);
  
      grabber.stop();
  
  }catch (FrameGrabber.Exception ex) {
  
      throw new IOException("Could not open video file ", ex);
  
  }

  As I said before, when the video exists, everything works perfectly, but when there is no video source, the program stays in the grabber.start () and I can not get out of there.

  I would like that when 5 seconds pass, it generates an exception and leaves the grabber.satart () function. I use grabber.setOption("stimeout", String.valueOf(5*1000000)) ; to controlate it but don’t work in RTP.

  I have checked the operation with RTSP video source and the code works perfectly, that is, after 5 seconds it generates an exception ... but I need to control the RTP video source.

  Someone could help me, thanks.

• How to stream H.264 bitstream to browser

  21 janvier 2019, par BobtheMagicMoose

  This is a followup to https://raspberrypi.stackexchange.com/questions/93254/stream-usb-webcam-with-audio?noredirect=1#comment150507_93254

  I, like many other brave tinkerers before me, thought it would be a simple task to take an old USB camera (c920) can pair it with a raspberry pi to make a network streaming device (e.g., baby monitor). As those that have gone before me, I have now realized (after two days of tearing my hair out), that this is an extremely complicated task.

  Problem statement : I have a raspberry pi zero and a c920 webcam. I want to use the H.264 bitstream from the webcam and serve it on the pi without transcoding it (the feeble processor would really struggle). I want to combine the video stream with its audio and send it over to a browser (phone, tablet, pc - something HTML5 without NAPI).

  My current strategy is to do the following :

  ffmpeg -re -f s16le -i /dev/zero -f v4l2 -thread_queue_size 512 -codec:v h264 -s 1920x1080 -i /dev/video0 -codec:v copy -acodec aac -ab 128k -g 50 http://localhost:8090/camera.ffm (this is with dummy audio - I figured I would add audio later)

  Followed by sudo ffserver -d -f /etc/ffserver.conf to received the feed and broadcast it as a stream. This is the ffserver.conf file :

  `HTTPPort 8090
  
  HTTPBindAddress 0.0.0.0
  
  MaxHTTPConnections 2000
  
  MaxClients 1000
  
  MaxBandwidth 100000
  
  CustomLog -
  
  <feed>
  
    File /tmp/streamwebm.ffm
  
    FileMaxSize 50M
  
    ACL allow localhost
  
    ACL allow 128.199.149.46
  
    #ACL allow 127.0.0.1
  
    ACL allow 192.168.0.0 192.168.0.255
  
  </feed>
  
  <stream stream="stream">
  
  Format webm
  
  
  
  # Video Settings
  
  VideoFrameRate 30
  
  VideoSize 1920x1080
  
  
  
  # Audio settings
  
  AudioCodec libvorbis
  
  AudioSampleRate 48000
  
  AVOptionAudio flags +global_header
  
  
  
  MaxTime 0
  
  AVOptionVideo me_range 16
  
  AVOptionVideo qdiff 4
  
  AVOptionVideo qmin 4
  
  AVOptionVideo qmax 40
  
  #AVOptionVideo good
  
  AVOptionVideo flags +global_header
  
  
  
  # Streaming settings
  
  PreRoll 10
  
  StartSendOnKey
  
  
  
  Metadata author "author"
  
  Metadata copyright "copyright"
  
  Metadata title "Web app name"
  
  Metadata comment "comment"
  
  </stream>

  My basic html is<video>  <source src="http://localhost:8090/stream"> </source></video>

  The stream however, doesn’t work (the browser won’t connect) and I get the following :
  

  And the browser on the client says (failed) NET::ERR_CONNECTION_REFUSED

  Thoughts :
   Begin stream simple mp4 with ffserver explains that ffserver can’t stream .mp4 because of headers or something. This is why I am using webm (which doesn’t support h.264 I believe and is causing the really slow performance converting to vp9). I’m not concerned about CPU usage at the moment, just want to get an image to appear on the browser !

  • I hear one issue deals with ’chunking’ - that the camera h.264 is a bitstream but h.264 streams for html5 should be chunked. Not sure how that would work.

  • I have tried VLC for some things (RTP) but haven’t have success.

  • Most resources (SE and other sites) are from 2010-2015 and it seems as thought v4l2 and other things have developed since then.

  • As my problem is most likely general ignorance of the subject matter, I would appreciate any answers that provide some general understanding as to the theory behind different techniques. I know this makes the question more of a call for opinion and less appropriate for SE, but I’m fixing to throw my computer out the window (you know the feeling).

  Thank you !

• Problems with timeout when there is no video source with RTP format

  22 février 2019, par Javier Dalmau Fajardo

  I have problems with the timeout when there is no video source with RTP format.

  If I execute the code and there is no video, the program stays waiting in the grabber.Start() function all the time.

  FFmpegFrameGrabber grabber;
  
  try{
  
      Frame img;        
  
      grabber = new FFmpegFrameGrabber("rtp://" + ip + ":1234");
  
      grabber.setOption("stimeout", String.valueOf(5*1000000));
  
      grabber.Start ();
  
      img = grabber.grab();
  
      Java2DFrameConverter converter = new Java2DFrameConverter();
  
  BufferedImage bufferedImag;
  
  bufferedImag = converter.convert(img);
  
      grabber.stop();
  
  }catch (FrameGrabber.Exception ex) {
  
      throw new IOException("Could not open video file ", ex);
  
  }

  As I said before, when the video exists, everything works perfectly, but when there is no video source, the program stays in the grabber.start () and I can not get out of there.

  I would like that when 5 seconds pass, it generates an exception and leaves the grabber.satart() function. I use grabber.setOption("stimeout", String.valueOf (5*1000000)); to controlate it but don’t work in RTP.

  I have checked the operation with RTSP video source and the code works perfectly, that is, after 5 seconds it generates an exception... But I need to control the RTP video source.