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• Can't lock std::mutex again

  16 juillet 2017, par user3567631

  Sorry for poor English.
  I referenced this FFMPEG to make ffmpeg decoder.
  The open will block, I make it run in detach thread.
  I added std::unique_lock to lock mutex in beginning of open.

  bool FFmpegWrapper::open(std::string strFileName)
  
  {
  
  std::unique_lock lock(g_Mutex, std::try_to_lock);
  
  
  
  m_pFormatContext = avformat_alloc_context();
  
  m_pFormatContext->probesize = 4 * 1024 *100;
  
  m_pFormatContext->max_analyze_duration = 0 * AV_TIME_BASE;
  
  
  
  if (avformat_open_input(&m_pFormatContext, strFileName.c_str(), nullptr, nullptr) != 0)
  
      return false; 
  
  
  
  if (avformat_find_stream_info(m_pFormatContext, NULL) < 0)
  
      return false; 
  
  
  
  m_iVideoStream = m_iAudioStream = -1;
  
  for (unsigned int i = 0; i < m_pFormatContext->nb_streams; i++)
  
  {
  
      if ((m_iVideoStream < 0) && (m_pFormatContext->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO))
  
      {
  
          m_iVideoStream = i;
  
      }
  
      else if ((m_iAudioStream < 0) && (m_pFormatContext->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO))
  
      {
  
          m_iAudioStream = i;
  
      }
  
  }
  
  
  
  if (!(hasVideo() || hasAudio()))
  
      return false; // Didn't find video or audio stream
  
  
  
  if (hasVideo())
  
  {
  
      if (!openVideoStream())
  
          return false;
  
  }
  
  
  
  if (hasAudio())
  
  {
  
      if (!openAudioStream())
  
          return false;
  
  }
  
  
  
  retrieveFileInfo();
  
  
  
  m_bIsFileOpen = true;
  
  m_strFileName = strFileName;
  
  
  
  if (isImage())
  
  {
  
      m_dDurationInMs = 0;
  
      m_dFps = 0;
  
      m_lCurrentFrameNumber = 1;
  
      decodeImage();
  
  }
  
  
  
  m_bIsThreadRunning = false;
  
  if (m_bIsFileOpen)
  
      CCLOG("FFmpeg open stream succeed");
  
  else
  
      CCLOG("FFmpeg open stream failed"); 
  
  m_iState = eOpened;
  
  
  
  return m_bIsFileOpen;
  
  }

  and added unique_lock in close beginning like this.

  void FFmpegWrapper::close()
  
  {
  
  std::unique_lock lock(g_Mutex, std::try_to_lock);
  
  while (!lock.owns_lock()) 
  
  { 
  
      lock.try_lock()
  
  }
  
  
  
  stop(); 
  
  
  
  if (m_pVideoBuffer != nullptr)
  
  {
  
      delete m_pVideoBuffer;
  
      m_pVideoBuffer = nullptr;
  
  }
  
  
  
  if (m_pVideoFrameRGB != nullptr)
  
  {
  
      av_free(m_pVideoFrameRGB);
  
      m_pVideoFrameRGB = nullptr;
  
  }
  
  
  
  if (m_pVideoFrame != nullptr)
  
  {
  
      av_free(m_pVideoFrame);
  
      m_pVideoFrame = nullptr;
  
  }
  
  
  
  if (m_pAudioFrame != nullptr)
  
  {
  
      av_free(m_pAudioFrame);
  
      m_pAudioFrame = nullptr;
  
  }
  
  
  
  
  
  if (m_pSwScalingContext != nullptr)
  
  {
  
      sws_freeContext(m_pSwScalingContext);
  
      m_pSwScalingContext = nullptr;
  
  }
  
  
  
  if (m_pVideoCodecContext != nullptr)
  
  {
  
      avcodec_close(m_pVideoCodecContext);
  
      m_pVideoCodecContext = nullptr;
  
  }
  
  if (m_pAudioCodecContext != nullptr)
  
  {
  
      avcodec_close(m_pAudioCodecContext);
  
      m_pAudioCodecContext = nullptr;
  
  }
  
  
  
  if (m_pFormatContext != nullptr)
  
  {
  
      avformat_free_context(m_pFormatContext);    
  
      m_pFormatContext = nullptr;
  
  }
  
  if(m_pSwr != nullptr)
  
      swr_free(&m_pSwr);
  
  
  
  CCLOG("CLOSE DONE");
  
  }

  When open is still running ,I want lock mutex again in close in main thread.
  it failed to get mutex ownership it is no problem. But even while loop waited the open() done, try_lock still can’t get the mutex ownership.I thought unique_lock out of scope will unlock mutex ,but it didn’t. I want to know how can I lock the mutex correctly.Thank you !

• Artifacts after HEVC 10-bit encoding using NVENC

  18 juillet 2017, par Cryman

  Recently I purchased a brand new GPU - AORUS GeForce GTX 1080 Ti. I found out that it supports HEVC 10-bit encoding, so I wanted to give that a try. Unfortunately, after encoding I noticed some artifacts, which occur in dark scenes and last one frame of the video. You can see them on these screenshots :

  

  

  I was wondering if someone could help me figure out what might be the cause of these artifacts and how I can get rid of them.

  Here is the MI of the source video :

  ID                                       : 1
  
  Format                                   : AVC
  
  Format/Info                              : Advanced Video Codec
  
  Format profile                           : High@L4.1
  
  Format settings, CABAC                   : Yes
  
  Format settings, ReFrames                : 4 frames
  
  Codec ID                                 : V_MPEG4/ISO/AVC
  
  Duration                                 : 2 h 2 min
  
  Bit rate mode                            : Variable
  
  Bit rate                                 : 29.5 Mb/s
  
  Maximum bit rate                         : 37.0 Mb/s
  
  Width                                    : 1 920 pixels
  
  Height                                   : 1 080 pixels
  
  Display aspect ratio                     : 16:9
  
  Frame rate mode                          : Constant
  
  Frame rate                               : 23.976 (24000/1001) FPS
  
  Color space                              : YUV
  
  Chroma subsampling                       : 4:2:0
  
  Bit depth                                : 8 bits
  
  Scan type                                : Progressive
  
  Bits/(Pixel*Frame)                       : 0.593
  
  Stream size                              : 25.2 GiB (66%)
  
  Language                                 : English
  
  Default                                  : Yes
  
  Forced                                   : No

  And here is the MI of the encoded video :

  ID                                       : 1
  
  Format                                   : HEVC
  
  Format/Info                              : High Efficiency Video Coding
  
  Format profile                           : Main 10@L4@Main
  
  Codec ID                                 : V_MPEGH/ISO/HEVC
  
  Duration                                 : 2 h 2 min
  
  Bit rate                                 : 3 689 kb/s
  
  Width                                    : 1 920 pixels
  
  Height                                   : 800 pixels
  
  Display aspect ratio                     : 2.40:1
  
  Frame rate mode                          : Constant
  
  Frame rate                               : 23.976 (24000/1001) FPS
  
  Standard                                 : Component
  
  Color space                              : YUV
  
  Chroma subsampling                       : 4:2:0
  
  Bit depth                                : 10 bits
  
  Bits/(Pixel*Frame)                       : 0.100
  
  Stream size                              : 3.15 GiB (95%)
  
  Default                                  : Yes
  
  Forced                                   : No
  
  Color range                              : Limited

  The command I’m using for encoding :

  ffmpeg -hide_banner -i "" -map 0:v:0 -map_chapters -1 -map_metadata -1 -vf "crop=1920:800:0:140" -vcodec hevc_nvenc -pix_fmt p010le -preset hq -profile:v main10 -rc constqp -global_quality 21 -rc-lookahead 32 -g 240 -f matroska Video_CQP21_LAF32_GOP240.mkv

• Piwik PRO is hiring a Technical Support Specialist (Remote)

  13 mars 2015, par Piwik Core Team — Jobs

  At Piwik and Piwik PRO we develop the leading open source web analytics platform, used by more than one million websites worldwide. Our vision is to build the best open alternative to Google Universal Analytics. We are growing and now looking for a Technical Support Specialist !

  What will you be doing ?

  • Supporting Piwik PRO clients on a daily basis – providing rapid responses via phone and email.
  • Participating in calls with Piwik PRO clients analyzing requirements for enterprise customers.
  • Onboarding clients – planning and coordinating the implementation with the dedicated technical team.
  • Communicating complex problems to the dedicated technical team.

  We can promise you :

  • A competitive salary.
  • The opportunity to develop your skills and gain more experience by working on exceptional projects.
  • Access to a regularly updated resource library and the opportunity to contribute to it.
  • Flexible working hours.

  Desired Skills and Experience

  You won’t make it without :

  • A solid technical background and a familiarity with the IT sector.
  • A receptive mind.
  • Great English communication skills (speaking, reading, writing, and listening).
  • Previous experience of working with corporate clients and a sixth sense for striking up relationships.
  • Appropriately mixed abilities : solid communication skills, inquisitiveness and an analytical mind (have the ability to draw conclusions based on gathered data).
  • Great self-organization skills.

  About Piwik PRO

  At Piwik and Piwik PRO we develop the leading open source web analytics platform, used by over 1.1M websites worldwide and is currently ranked the 7th most used web analytics tool in the world. Our vision is to build the best open alternative to Google Universal Analytics.

  The Piwik platform collects, stores and processes a lot of information : hundreds of millions of data points each month. We create intuitive, simple and beautiful reports that delight our users.

  Piwik PRO provides cloud hosting solutions and enterprise-level support and consultancy services. We’re in the process of expanding our US team and are currently seeking to hire a Technical Support Specialist who will focus on assisting our US clients.

  Location

  Ideally you will be located in the USA or Canada (Remote work).

  Apply online

  To apply for this position, please Apply online here. We look forward to receiving your applications !