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• tests : Remove fate-libx265-hdr10

  22 mars 2024, par Zhao Zhili

  tests : Remove fate-libx265-hdr10
  The test depends on the compile option of x265. It failed when
  
  HIGH_BIT_DEPTH isn't enabled. It also failed when asan is enabled
  
  because of memory issue inside of x265, which I don't think can
  
  be fixed within FFmpeg.
  Signed-off-by : Zhao Zhili <zhilizhao@tencent.com>
  

  • [DH] tests/fate/enc_external.mak
  • [DH] tests/ref/fate/libx265-hdr10

• Header missing in mpg, in spite of using avformat_write_header

  23 novembre 2012, par TheSHEEEP

  I am encoding a live rendered video to mpg and/or mp4 (depends on the later usage of the video) using the ffmpeg C API. When encoding to mp4, everything is well. But when encoding to mpg, the resulting video cannot be played by any player. A quick call to ffprobe on it reveals that the header is missing. But this seems pretty much impossible, as I am explicitly writing it.

  This is how I write the header, before any frame is encoded :

  // ptr->oc is the AVFormatContext
  
  int error = avformat_write_header(ptr->oc, NULL);
  
  if (error < 0)
  
  {
  
      s_logFile << "Could not write header. Error: " << error << endl;
  
      fprintf(stderr, "Could not write header. Error: '%i'\n", error);
  
      return 1;
  
  }

  There never is any error when writing the header.

  For encoding, I am following the official muxing.c example, so I do set the CODEC_FLAG_GLOBAL_HEADER flag. I use CODEC_ID_MPEG2VIDEO (for video) and CODEC_ID_MP2 (for audio).

  The result mpg does work when I "encode" it in an additional step with an external ffmpeg executable like this : "ffmpeg -i ownEncoded.mpg -sameq -y working.mpg".
  So it seems all the data is there, only the header is missing for some reason...

  Here is the only thing ffmpeg is reporting before/when writing the header :

  mpeg -------------------
  
  lvl: 24
  
  msg: VBV buffer size not set, muxing may fail

  Could that be the problem ?

  I wonder what could be wrong here as I encode mp4 with the exact same function, except setting some special values like qmin, qmax, me_method, etc. when encoding to mp4. Do I probably have to set any special values so that ffmpeg really does write the header correctly ?

• Different ways of embedding the Piwik tracking code for faster website performance

  18 avril 2017, par InnoCraft — Community, Development

  Many studies have shown that performance matters a lot. For each 100ms a websites takes longer to load, a business may lose about 0.1% to 1% in revenue. It also matters because Google judges page speed as a ranking factor for search results page. At InnoCraft, we help our clients optimizing their Piwik integration and recommend different ways of embedding the tracking code tailored to their needs. The best way to embed the tracking code depends on your website, what you want to achieve, and how important tracking is to you.

  This technical blog post mainly focuses on improving the time to load your website. This is an important metric as for example Google usually measures the time it took to load a page. Many businesses therefore want to get to the page load event as quickly as possible.

  The regular way of embedding the tracking code

  By default, Piwik is embedded in the header or footer of your website. This is a sensible default. While it is loaded asynchronously and deferred, it still does delay the onload event. Depending on the performance of your Piwik, how fast your website loads, how your website’s resources are embedded, and other factors you may want to consider alternatives. Three of them I will introduce below.

  Embedding the tracker after the load event

  To ensure that your website will always load even if the Piwik server is un-available, you may want to load the tracking code only after the website is loaded like this :

  var _paq = _paq || [];
  
  _paq.push(["trackPageView"]);
  
  _paq.push(["enableLinkTracking"]);
  
  
  
  function embedTrackingCode() {
  
     var u="https://your.piwik.domain/";
  
     _paq.push(["setTrackerUrl", u+"piwik.php"]);
  
     _paq.push(["setSiteId", "1"]);
  
  
  
     var d=document, g=d.createElement("script"), s=d.getElementsByTagName("script")[0]; g.type="text/javascript";
  
     g.defer=true; g.async=true; g.src=u+"piwik.js"; s.parentNode.insertBefore(g,s);    
  
  }
  
  
  
  if (window.addEventListener) { 
  
      window.addEventListener("load", embedTrackingCode, false); 
  
  } else if (window.attachEvent) { 
  
      window.attachEvent("onload",embedTrackingCode); 
  
  } else {
  
      embedTrackingCode();
  
  }

  The downside is you won’t track all of your visitors because some will have already left your website by the time your website is fully loaded. Especially when you have a JavaScript-heavy website or when your website takes longer to load in general. To detect the load event correctly cross browser, you may want to use a library like jQuery.

  Delaying the tracking

  Another technique is to load the tracking with a little delay at the end of your website like this :

  setTimeout(function () {
  
      embedTrackingCode();
  
  }, 5);

  This time the tracking script will still track most of your visitors but does not slow down loading the rest of your website as much as it would do by default (at least perceived). In some cases, you will notice a performance improvement when looking at the “time to load” but it depends on your website.

  Not loading the JavaScript Tracker at all

  With Piwik you also have the option to not embed the tracking code into your websites at all and instead generate reports from the webserver logs using Piwik Log Analytics. This works very well but some data might not be available like the device resolution which can be only captured using JavaScript. On the bright side this solution also captures users with ad blockers or tracking blockers.

  Questions ?

  We invite you to test different ways to see what makes sense for you and how it affects your website performance as well as the perceived performance. If you have any questions, feel free to get in touch with us.

  Read on

  The last post in this series is Performance optimizations you can apply today to load the Piwik JavaScript tracker faster.