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• Read H264 streaming from Elp H264 with OpenCV + Python

  3 février 2017, par Francesco Paissan

  I’m trying to read an udp streaming of a H264 encoded image. The software structure is like follows :

  On a BeagleBoneBlack (Ubuntu 16.04) I’ve an Elp H264 cam (see here : https://www.amazon.com/ELP-Support-Android-Windows-Surveillance/dp/B00VDSBH9G ). I stream frames with ffmpeg on a Unicast UDP Stream.

  I want to read this images from python and opencv to be able to process them.

  I tried with this simple code to see if the cap is opened or not :

  import cv2

  try:
  
       cap = cv2.VideoCapture("udp://localhost:1234/")
  
      cap.set(CV_CAP_PROP_FOURCC, CV_FOURCC('H', '2', '6', '4'));
  
  except Exception, e:
  
      print str(e)

  But when I run this script python says :

  DtsGetHWFeatures : Create File Failed DtsGetHWFeatures : Create File
  Failed Running DIL (3.22.0) Version DtsDeviceOpen : Opening HW in mode
  0 DtsDeviceOpen : Create File Failed libva info : VA-API version 0.38.1
  libva info : va_getDriverName() returns -1 libva error :
  va_getDriverName() failed with unknown libva error,driver_name=(null)
  libva info : VA-API version 0.38.1 libva info : va_getDriverName()
  returns -1 libva error : va_getDriverName() failed with unknown libva
  error,driver_name=(null) libva info : VA-API version 0.38.1 libva info :
  va_getDriverName() returns -1 libva error : va_getDriverName() failed
  with unknown libva error,driver_name=(null) libva info : VA-API version
  0.38.1 libva info : va_getDriverName() returns -1 libva error : va_getDriverName() failed with unknown libva error,driver_name=(null)
  GStreamer Plugin : Embedded video playback halted ; module vaapidecode
  reported : Could not initialize supporting library. OpenCV
  Error : Unspecified error (GStreamer : unable to start pipeline ) in
  cvCaptureFromCAM_GStreamer, file /builddir/build/BUILD/opencv-
  2.4.12.3/modules/highgui/src/cap_gstreamer.cpp, line 816 /builddir/build/BUILD/opencv-2.4.12.3/modules/highgui/src/cap_gstreamer.cpp:816 :
  error : (-2) GStreamer : unable to start pipeline in function
  cvCaptureFromCAM_GStreamer

  Can anybody help me ?

  Thanks,

  Francesco.

• Read H264 streaming from Elp H264 with OpenCV + Pyhton

  15 janvier 2017, par Francesco Paissan

  I’m trying to read an udp streaming of a H264 encoded image. The software structure is like follows :

  On a BeagleBoneBlack (Ubuntu 16.04) I’ve an Elp H264 cam (see here : https://www.amazon.com/ELP-Support-Android-Windows-Surveillance/dp/B00VDSBH9G ). I stream frames with ffmpeg on a Unicast UDP Stream.

  I want to read this images from python and opencv to be able to process them.

  I tried with this simple code to see if the cap is opened or not :

  import cv2

  try:
  
       cap = cv2.VideoCapture("udp://localhost:1234/")
  
      cap.set(CV_CAP_PROP_FOURCC, CV_FOURCC('H', '2', '6', '4'));
  
  except Exception, e:
  
      print str(e)

  But when I run this script python says :

  DtsGetHWFeatures : Create File Failed DtsGetHWFeatures : Create File
  Failed Running DIL (3.22.0) Version DtsDeviceOpen : Opening HW in mode
  0 DtsDeviceOpen : Create File Failed libva info : VA-API version 0.38.1
  libva info : va_getDriverName() returns -1 libva error :
  va_getDriverName() failed with unknown libva error,driver_name=(null)
  libva info : VA-API version 0.38.1 libva info : va_getDriverName()
  returns -1 libva error : va_getDriverName() failed with unknown libva
  error,driver_name=(null) libva info : VA-API version 0.38.1 libva info :
  va_getDriverName() returns -1 libva error : va_getDriverName() failed
  with unknown libva error,driver_name=(null) libva info : VA-API version
  0.38.1 libva info : va_getDriverName() returns -1 libva error : va_getDriverName() failed with unknown libva error,driver_name=(null)
  GStreamer Plugin : Embedded video playback halted ; module vaapidecode
  reported : Could not initialize supporting library. OpenCV
  Error : Unspecified error (GStreamer : unable to start pipeline ) in
  cvCaptureFromCAM_GStreamer, file /builddir/build/BUILD/opencv-
  2.4.12.3/modules/highgui/src/cap_gstreamer.cpp, line 816 /builddir/build/BUILD/opencv-2.4.12.3/modules/highgui/src/cap_gstreamer.cpp:816 :
  error : (-2) GStreamer : unable to start pipeline in function
  cvCaptureFromCAM_GStreamer

  Can anybody help me ?

  Thanks,

  Francesco.

• PipedInputStream / PipedOutputStream, ImageIO and ffmpeg

  19 avril 2015, par jdevelop

  I have the following code in Scala :

        val pos = new PipedOutputStream()
  
        val pis = new PipedInputStream(pos)
  
  
  
        Future {
  
          LOG.trace("Start rendering")
  
          generateFrames(videoRenderParams.length) {
  
            img ⇒ ImageIO.write(img, "PNG", pos)
  
          }
  
          pos.flush()
  
          IOUtils.closeQuietly(pos)
  
          LOG.trace("Finished rendering")
  
        } onComplete {
  
          case Success(_) ⇒ 
  
            LOG.trace("Complete successfully")
  
          case Failure(err) ⇒
  
            LOG.error("Can't render stuff", err)
  
            IOUtils.closeQuietly(pis)
  
            IOUtils.closeQuietly(pos)
  
        }
  
  
  
        val prc = (ffmpegCli #< pis).!(logger)

  the Future simply writes the generated images one by one to the OutputStream. Now the ffmpeg process reads the input images from stdin and converts them to MP4 file.

  That works pretty well, but for some reason sometimes I’m getting the following stacktraces :

  I/O error Pipe closed for process: <input stream="stream" />
  
  java.io.IOException: Pipe closed
  
      at java.io.PipedInputStream.checkStateForReceive(PipedInputStream.java:260)
  
      at java.io.PipedInputStream.receive(PipedInputStream.java:226)
  
      at java.io.PipedOutputStream.write(PipedOutputStream.java:149)
  
      at scala.sys.process.BasicIO$.loop$1(BasicIO.scala:236)
  
      at scala.sys.process.BasicIO$.transferFullyImpl(BasicIO.scala:242)
  
      at scala.sys.process.BasicIO$.transferFully(BasicIO.scala:223)
  
      at scala.sys.process.ProcessImpl$PipeThread.runloop(ProcessImpl.scala:159)
  
      at scala.sys.process.ProcessImpl$PipeSource.run(ProcessImpl.scala:179)

  At the same time I’m getting the following error from another stream :

  javax.imageio.IIOException: I/O error writing PNG file!
  
      at com.sun.imageio.plugins.png.PNGImageWriter.write(PNGImageWriter.java:1168)
  
      at javax.imageio.ImageWriter.write(ImageWriter.java:615)
  
      at javax.imageio.ImageIO.doWrite(ImageIO.java:1612)
  
      at javax.imageio.ImageIO.write(ImageIO.java:1578)
  
      at 

  So it seems that the streams were broken somewhere in between, so ffmpeg can not read the data, and ImageIO can not write the data.

  What is even more interesting - the problem is reproducible only on certain Linux server (Amazon). It works flawlessly on other Linux boxes. So I wonder if somebody could point me out to the possible causes of this error.

  What I’ve tried so far :

  • use Oracle JDK 8 and OpenJDK
  • use different versions of FFMPEG

  Nothing worked by the moment.