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• 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.

• confused about lhls in ffmpeg

  27 décembre 2020, par JohnL

  I am more than a little confused about trying to use the experimental lhls option in ffmpeg.

  


  I have built ffmpeg from source (which takes a while), and currently have version 4.1.6 running.

  


  Reading other threads here, and the ffmpeg docs, it appears that the lhls option is available only in the Dash muxer.

  


  I gravitated to HLS because of its support in Apple devices, and I thought that lhls was related (and Apple was drafting the spec).

  


  Then there is the comment in the ffmpeg docs that states that the hls.js folks are working on supporting lhls in their library, which I also use to support browsers like Chrome.

  


  Should I be using dash instead of hls for my prototype ? I want to try and get very low latency for a construction inspection app I am considering building. Right now, the latency I am seeing is 10-15 seconds.

  


  Any insights would be appreciated. TIA

  


  See my comment below. I have many of the dash format flags working, but can't get -lhls to work. Here are some of the build flags used :

  


  conversion : avcodec configuration : —prefix=/usr —extra-version='1 deb10u1+rpt1' —toolchain=hardened —incdir=/usr/include/arm-linux-gnueabihf —enable-gpl —disable-stripping —enable-avresample —disable-filter=resample —enable-avisynth —enable-gnutls —enable-ladspa —enable-libaom —enable-libass —enable-libbluray —enable-libbs2b —enable-libcaca —enable-libcdio —enable-libcodec2 —enable-libflite —enable-libfontconfig —enable-libfreetype —enable-libfribidi —enable-libgme —enable-libgsm —enable-libjack —enable-libmp3lame —enable-libmysofa —enable-libopenjpeg —enable-libopenmpt —enable-libopus —enable-libpulse —enable-librsvg —enable-librubberband —enable-libshine —enable-libsnappy —enable-libsoxr —enable-libspeex —enable-libssh —enable-libtheora —enable-libtwolame —enable-libvidstab —enable-libvorbis —enable-libvpx —enable-libwavpack —enable-libwebp —enable-libx265 —enable-libxml2 —enable-libxvid —enable-libzmq —enable-libzvbi —enable-lv2 —enable-omx —enable-openal —enable-opengl —enable-sdl2 —enable-omx-rpi —enable-mmal —enable-neon —enable-rpi —enable-libdc1394 —enable-libdrm —enable-libiec61883 —enable-chromaprint —enable-frei0r —enable-libx264 —libdir=/usr/lib/arm-linux-gnueabihf/neon/vfp —cpu=cortex-a7 —arch=armv6t2 —disable-thumb —enable-shared —disable-doc —disable-programs

  


• 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.