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• mov : Make sure the read sample count is nonnegative

  28 septembre 2013, par Martin Storsjö

  mov : Make sure the read sample count is nonnegative
  This avoids setting a negative number of frames, ending up with a
  
  negative average frame rate.
  Reported-by : Mateusz "j00ru" Jurczyk and Gynvael Coldwind
  
  CC : libav-stable@libav.org
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavformat/mov.c

• Ffmpeg decode H264 video from RTP stream very slow

  3 octobre 2013, par Dmitry Bakhtiyarov

  I have H264 RTP stream over network and I need to decode it. I use libx264 to encode stream and ffmpeg to decode. When I connect to server using VLC, it correct play video without any problem. But when I connect to server using my application I have a long period, when widget, which draw video from this stream, draw only one image.

  I check log file and found, that avcodec_decode_video2() set got_image into 1 very rarely ! Decoder give me new decoded frame average every 1-2 seconds, but on the server I have 12-15 fps on encoder !

  What the reasons of this delays on decoder and how I can fix its ?

  avcodec_register_all();
  
  av_init_packet(&m_packet);
  
  m_decoder = avcodec_find_decoder(CODEC_ID_H264);
  
  if (!m_decoder)
  
  {
  
      QString str = QString("Can't find H264 decoder!");
  
      emit criticalError(str);
  
  }
  
  m_decoderContext = avcodec_alloc_context3(m_decoder);
  
  
  
  m_decoderContext->flags |= CODEC_FLAG_LOW_DELAY;
  
  m_decoderContext->flags2 |= CODEC_FLAG2_CHUNKS;
  
  AVDictionary* dictionary = nullptr;
  
  if (avcodec_open2(m_decoderContext, m_decoder, &dictionary) < 0)
  
  {
  
      QString str = QString("Failed to open decoder!");
  
      emit criticalError(str);
  
  }
  
  qDebug() << "H264 Decoder successfully opened";
  
  m_picture = avcodec_alloc_frame();
  
  ...
  
      while(m_packet.size > 0)
  
      {
  
          int got_picture;
  
          int len = avcodec_decode_video2(m_decoderContext, m_picture, &got_picture, &m_packet);
  
          if (len < 0)
  
          {
  
              QString err("Decoding error");
  
              qDebug() << err;
  
              //emit criticalError(err);
  
              return false;
  
          }
  
          if (got_picture)
  
          {
  
                  //create from frame QImage and send it into GUI thread
  
              qDebug() << "H264Decoder: frame decoded!";

  I try to change some options of m_decoderContext (i.e. thread_count) but this not changing anything.

• How many "Ruby on Rails" sites can be hosted using sub url in apache configuration file on apache4 with passenger4 on Ubuntu server ?

  17 octobre 2013, par user1731249

  Server's Hardware config :
  Ubuntu server 12.04, CPU : dual code (64-bit), RAM : 8GB, Disk : 200GB.

  Server's Software config :
  Apache2, Passenger4, Rails4, ruby2, MySQL.

  I'm developing a Ruby on Rails website which performs following tasks.

  1. Upload a series of images as zip.
  2. Extract zip images to temp directory.
  3. Convert series of images to video using FFMPEG.
  4. updating video info in MySQL db
  5. Viewing the video in HTML5 video tag.

  Maximum length of single video being 1min and on an average there may be 50 videos to be converted per day. I created three copies (Don't ask me why !) of same website and hosting three sites as sub-URLs like "example.com" being the domain and example.com/site1, example.com/site2, example.com/site3. Below is the Apache configuration :
  RailsAutoDetect off

  ServerName 127.0.0.1

      DocumentRoot /home/ubuntuuser/work/public
  
      ErrorDocument 404 /404.html
  
  
  
  RailsBaseURI /site1
  
  
  
      <directory></directory>home/ubuntuuser/work/site1/advisor/public>
  
              Allow from all
  
      Options -MultiViews
  
              RailsEnv production
  
      
  
  
  
  RailsBaseURI /site2
  
  
  
  <directory></directory>home/ubuntuuser/work/site2/advisor/public>
  
              Allow from all
  
      Options -MultiViews
  
              RailsEnv production
  
      
  
  
  
      RailsBaseURI /site3
  
  
  
  <directory></directory>home/ubuntuuser/work/site3/advisor/public>
  
              Allow from all
  
      Options -MultiViews
  
              RailsEnv production
  
      

  How many such sites can I host with sub-URLs without big performance drag ?
  Also please help to do a performance test for all the sub-URLs.