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• Integrating CUDA-based video decoder into libavcodec/ffmpeg

  1er février 2019, par tmlen

  I have a CUDA-based decoder of a video format running on the GPU. I am trying to add a "codec" into libavcodec that uses it as external decoder

  Currenty, I have it working such that I can play a sequence of pictures using ffplay, which
  get decoded on the GPU with the external decoder.

  But with the current implementation, the codec module copies its output (in a RGB24 pixel format) from GPU memory to host memory after each frame, and gives this to libavcodec in its AVFrame. So with this when using ffplay, it will copy the output images back and forth between GPU and host two times (as ffplay has to copy the data to GPU for display).

  My goal is to leave the uncompressed data on GPU using on a CUDA device buffer, and have ffmpeg use it.

  ffmpeg seems to have support for this using AVHWAccel.

  • Is there any example implementation that uses this with a CUDA based decoder (not using the dedicated hardware decoders through NVDEC, CUVID, etc.) ?

  • Does ffmpeg need the output in a pixel format in a CUDA buffer, or can it also be in texture memory, in a CUDA array ?

  • Is it possible to have the hardware decoder as primary decoder of the AVCodec. It seems that hardware-acceleration is foreseen as an add-on, with the software decoder implemented by AVCodec available as fallback ?

  • It seems that ffmpeg will allocate a pool of CUDA buffers to receive its output. Is it also possible to allocate the output buffers oneself in the module’s implementation, and control how many buffers there will be.

  • Is it possible to control with how many CPU threads the decoder will be called ? With the external decoder’s interface, ideal would be one writer thread that pushes compressed codestreams, and one reader thread that pulls the uncompressed output to a CUDA buffer.

• How to take a video of what's happening in selenium

  5 février 2019, par fabio

  I’m using Selenium 3 webdriver and Python 3 in Windows 7.

  I want to record a video of what’s happening in my selenium tests.

  To do so I’m using FFmpeg and screen-capture-recorder but I can change programs.

  Here’s my code :

  import unittest
  
  from selenium import webdriver
  
  from subprocess import Popen
  
  #from subprocess import call
  
  
  
  
  
  cmd = 'ffmpeg -y -rtbufsize 2000M -f dshow -i video="screen-capture-recorder" -r 10 -t 20 screen-capture.mp4'
  
  
  
  class SearchProductTest(unittest.TestCase):
  
      def setUp(self):
  
  
  
          # start the recording of movie
  
          self.videoRecording = Popen(cmd)
  
  
  
          # create a new Firefox session
  
          self.driver = webdriver.Firefox()
  
          self.driver.implicitly_wait(30)
  
          self.driver.maximize_window()
  
  
  
          # navigate to the application home page
  
          self.driver.get("http://demo-store.seleniumacademy.com/")
  
  
  
      def test_search_by_category(self):
  
          # get the search textbox
  
          search_field = self.driver.find_element_by_name("q")
  
          search_field.clear()
  
  
  
          # enter search keyword and submit
  
          search_field.send_keys("phones")
  
          search_field.submit()
  
  
  
          # get all the anchor elements which have product names displayed
  
          # currently on result page using find_elements_by_xpath method
  
          products = self.driver.find_elements_by_xpath(
  
              "//h2[@class='product-name']/a")
  
  
  
          # check count of products shown in results
  
          self.assertEqual(3, len(products))
  
          #self.videoRecording.terminate()
  
  
  
      def test_something_else(self):
  
          pass
  
  
  
      def tearDown(self):
  
          # close the browser window
  
          self.driver.quit()
  
  
  
          # Stop the recording
  
          self.videoRecording.terminate()
  
  
  
      #def terminate(process):
  
          #if process.poll() is None:
  
          #    call('taskkill /F /T /PID ' + str(process.pid))
  
  
  
  if __name__ == '__main__':
  
      unittest.main(verbosity=2)

  The problems are :

  1) the cmd gives a max time per the movie (20" in the example). If the test last more the movie is created and it works (but is incomplete, only 20").

  2) if the test last less the file is created but it doesn’t work (the reader can’t read it and it’s just some bytes). This is the main error ! I’m not sure about where to start the movie and where (and how) to stop it.

  3) If I have more than one test I would like to have only one movie for all of them (so I want to record all the tests in the same movie).

  4) if possible I would prefer to record the webdriver window (the one where my tests are running) and not my screen so meanwhile the tests go I can do something else (they are slow).

  Thanks you for the help.

• Intel QuickSync error : Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  30 novembre 2018, par Arie Syamsudin

  I want to make IPTV with a topology like this :

  Restream / source -----> IPTV server -----> User

  The problem at the moment is the question of bandwidth that is still large.

  Finally I announced by IPTV software providers to transcode with Intel QuickSync video and FFmpeg.

  I followed the steps given by the software provider at the following link :
  http://www.ezhometech.com/document/intel_ffmpeg.txt

  Which comes from the link below :
  https://www.intel.com/content/dam/www/public/us/en/documents/white-paper...

  I installed IPTV software on a laptop with an Intel processor, chipset and VGA.

  [root@iptv ffmpeg-4.1]# **lspci**
  
  00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
  
  00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
  
  00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)
  
  00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 05)
  
  00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05)
  
  00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b5)
  
  00:1c.1 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 2 (rev b5)
  
  00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 05)
  
  00:1f.0 ISA bridge: Intel Corporation HM65 Express Chipset Family LPC Controller (rev 05)
  
  00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family 6 port Mobile SATA AHCI Controller (rev 05)
  
  00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 05)
  
  01:00.0 Ethernet controller: Qualcomm Atheros AR8152 v2.0 Fast Ethernet (rev c1)
  
  02:00.0 Network controller: Qualcomm Atheros AR9285 Wireless Network Adapter (PCI-Express) (rev 01)
  
  
  
  [root@iptv ffmpeg-4.1]# **lspci -nn -s 0:02.0**
  
  00:02.0 VGA compatible controller [0300]: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09)

  but when I do a transcoding test, an error always appears :
  Error initializing output stream 0:0 — Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height.

  Error details :
  https://paste.fedoraproject.org/paste/vp9XIzbeOuyXRuLBlLfSng

  FFmpeg log :

  ./ffmpeg  -hwaccel qsv -i http://premium-play.org:8000/domm0H56Cj/q3ODLP6C16/2826 -vcodec h264_qsv -acodec copy -b:v 1200K -f mpegts udp://127.0.0.1:9011?pkt_size=1316
  
  ffmpeg version 3.2.12 Copyright (c) 2000-2018 the FFmpeg developers
  
    built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-28)
  
    configuration: --enable-libmfx --enable-nonfree
  
    libavutil      55. 34.101 / 55. 34.101
  
    libavcodec     57. 64.101 / 57. 64.101
  
    libavformat    57. 56.101 / 57. 56.101
  
    libavdevice    57.  1.100 / 57.  1.100
  
    libavfilter     6. 65.100 /  6. 65.100
  
    libswscale      4.  2.100 /  4.  2.100
  
    libswresample   2.  3.100 /  2.  3.100
  
  Input #0, mpegts, from 'http://premium-play.org:8000/domm0H56Cj/q3ODLP6C16/2826':
  
    Duration: N/A, start: 30200.274878, bitrate: N/A
  
    Program 1
  
      Metadata:
  
        service_name    : Service01
  
        service_provider: FFmpeg
  
      Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], 50 fps, 50 tbr, 90k tbn, 100 tbc
  
      Stream #0:1[0x101]: Audio: aac (LC) ([15][0][0][0] / 0x000F), 48000 Hz, stereo, fltp, 125 kb/s
  
  libva info: VA-API version 1.0.0
  
  libva info: va_getDriverName() returns 0
  
  libva info: User requested driver 'iHD'
  
  libva info: Trying to open /opt/intel/mediasdk/lib64/iHD_drv_video.so
  
  libva info: Found init function __vaDriverInit_1_0
  
  libva info: va_openDriver() returns 0
  
  [h264_qsv @ 0x2a89500] Selected ratecontrol mode is not supported by the QSV runtime. Choose a different mode.
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> h264 (h264_qsv))
  
    Stream #0:1 -> #0:1 (copy)
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height