Recherche avancée

Sur d’autres sites (10165)

• 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.

• ffmpeg "Option preset not found."

  2 février 2015, par PiTheNumber

  I am trying to convert a .mpg to .flv with ffmpeg. On other servers I got it working but here with the ffmpeg clone (avconv) it just does not do it.

  Originally I was working with libfaac and preset fastfirstpass but thats not available in this build so I switched to the experimental acc and preset libx264-fast_firstpass :

  $ /usr/bin/ffmpeg -i /data/upload/videos/original/150128_Test_731_9d5b83.mpg
  
    -strict experimental -acodec aac -ab 128k -ar 44100 -vcodec libx264 -pass 1 
  
    -pre libx264-fast_firstpass -b 512k -s 360x204 
  
    -f flv /data/upload/videos/encoded/150129_Test_731_54f06a.flv
  
  
  
  avconv version 9.16-6:9.16-0ubuntu0.14.04.1, Copyright (c) 2000-2014 the Libav developers
  
    built on Aug 10 2014 18:16:02 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  
  [mpeg @ 0xc87de0] max_analyze_duration reached
  
  Guessed Channel Layout for  Input Stream #0.1 : stereo
  
  Input #0, mpeg, from '/data/upload/videos/original/150128_Test_731_9d5b83.mpg':
  
    Duration: 00:01:00.12, start: 0.989978, bitrate: 4814 kb/s
  
      Stream #0.0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x406 [PAR 406:405 DAR 16:9], 104857 kb/s, 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc
  
      Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, stereo, s16p, 224 kb/s
  
  [libx264 @ 0xc8b4c0] using SAR=136/135
  
  [libx264 @ 0xc8b4c0] MB rate (26910000) > level limit (2073600)
  
  [libx264 @ 0xc8b4c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2
  
  [libx264 @ 0xc8b4c0] profile Main, level 5.2
  
  [libx264 @ 0xc8b4c0] 264 - core 142 r2389 956c8d8 - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=1 ref=1 deblock=1:0:0 analyse=0x1:0 me=dia subme=2 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=3 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=1 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=30 rc=abr mbtree=1 bitrate=512 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.25 aq=1:1.00
  
  Option preset not found.

  What does the error in the last line mean ?

  I already made sure the preset libx264-fast_firstpass.avpreset exists in /usr/share/avconv/ and if I change it to invalid ffmpeg complains with Preset invalid specified for stream 0:0, but could not be opened., so the preset is correct.

  Google does provide two results for this error. This chatlog and it’s pastebin about live streaming with the solution to add -f flv and some russian page. Nothing helped.

  Any advice ?

• How to deal with "Buffer queue overflow, dropping." (ffmpeg)

  1er mai 2015, par whitesiroi

  Sometimes it works great and sometimes I’m getting this message
  [Parsed_overlay_0 @ 0x7f9520518800] [framesync @ 0x7f9521021e28] Buffer queue overflow, dropping.

  by running this command
  ffmpeg -i a1.mp4 -i watermark150x125.png -filter_complex 'overlay=10:10' output.mp4

  I tried different variation of "overlay" like overlay=W-w-5:H-h-5, overlay=10:main_h-overlay_h-10, overlay=main_w-overlay_w-10:main_h-overlay_h-10 - getting the same result.

  Here is the output of the ffmpeg command.

  ffmpeg version 2.6.2 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.6.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid --enable-vda
  
    libavutil      54. 20.100 / 54. 20.100
  
    libavcodec     56. 26.100 / 56. 26.100
  
    libavformat    56. 25.101 / 56. 25.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 11.102 /  5. 11.102
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f952101d200] stream 0, timescale not set
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'a1.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      artist          : a1
  
      album           :
  
      comment         : 
  
      date            : 0
  
      genre           :
  
      title           : a1
  
      encoder         : Lavf56.4.101
  
    Duration: 00:01:41.51, start: 0.000000, bitrate: 227 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 426x240 [SAR 1:1 DAR 71:40], 97 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
      Stream #0:2: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 120x90 [SAR 1:1 DAR 4:3], 90k tbr, 90k tbn, 90k tbc
  
  Input #1, png_pipe, from 'watermark150x125.png':
  
    Duration: N/A, bitrate: N/A
  
      Stream #1:0: Video: png, rgba, 150x125 [SAR 2835:2835 DAR 6:5], 25 tbr, 25 tbn, 25 tbc
  
  [swscaler @ 0x7f9521013e00] deprecated pixel format used, make sure you did set range correctly
  
  [libx264 @ 0x7f9521030e00] using SAR=1/1
  
  [libx264 @ 0x7f9521030e00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
  
  [libx264 @ 0x7f9521030e00] profile High, level 2.1
  
  [libx264 @ 0x7f9521030e00] 264 - core 144 r2533 c8a773e - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'output.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      artist          : a1
  
      album           :
  
      comment         : 
  
      date            : 0
  
      genre           :
  
      title           : a1
  
      encoder         : Lavf56.25.101
  
      Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 426x240 [SAR 1:1 DAR 71:40], q=-1--1, 29.97 fps, 30k tbn, 29.97 tbc (default)
  
      Metadata:
  
        encoder         : Lavc56.26.100 libx264
  
      Stream #0:1(und): Audio: aac (libvo_aacenc) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, s16, 128 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
        encoder         : Lavc56.26.100 libvo_aacenc
  
  Stream mapping:
  
    Stream #0:0 (h264) -> overlay:main (graph 0)
  
    Stream #0:2 (mjpeg) -> overlay:overlay (graph 0)
  
    overlay (graph 0) -> Stream #0:0 (libx264)
  
    Stream #0:1 -> #0:1 (aac (native) -> aac (libvo_aacenc))
  
  Press [q] to stop, [?] for help
  
  [Parsed_overlay_0 @ 0x7f9520518800] [framesync @ 0x7f9521021e28] Buffer queue overflow, dropping.
  
      Last message repeated 385 times
  
  [Parsed_overlay_0 @ 0x7f9520518800] [framesync @ 0x7f9521021e28] Buffer queue overflow, dropping.
  
      Last message repeated 564 times
  
  [Parsed_overlay_0 @ 0x7f9520518800] [framesync @ 0x7f9521021e28] Buffer queue overflow, dropping.
  
      Last message repeated 546 times
  
  [Parsed_overlay_0 @ 0x7f9520518800] [framesync @ 0x7f9521021e28] Buffer queue overflow, dropping.
  
      Last message repeated 569 times
  
  [Parsed_overlay_0 @ 0x7f9520518800] [framesync @ 0x7f9521021e28] Buffer queue overflow, dropping.
  
      Last message repeated 593 times
  
  [Parsed_overlay_0 @ 0x7f9520518800] [framesync @ 0x7f9521021e28] Buffer queue overflow, dropping.
  
      Last message repeated 312 times
  
  frame= 3041 fps=645 q=-1.0 Lsize=    1800kB time=00:01:41.52 bitrate= 145.3kbits/s dup=2975 drop=0
  
  video:149kB audio:1587kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 3.700745%
  
  [libx264 @ 0x7f9521030e00] frame I:14    Avg QP:19.91  size:  6947
  
  [libx264 @ 0x7f9521030e00] frame P:768   Avg QP:10.30  size:    27
  
  [libx264 @ 0x7f9521030e00] frame B:2259  Avg QP:13.67  size:    15
  
  [libx264 @ 0x7f9521030e00] consecutive B-frames:  0.9%  0.1%  0.1% 98.9%
  
  [libx264 @ 0x7f9521030e00] mb I  I16..4: 18.7% 59.0% 22.3%
  
  [libx264 @ 0x7f9521030e00] mb P  I16..4:  0.0%  0.0%  0.0%  P16..4:  0.1%  0.0%  0.0%  0.0%  0.0%    skip:99.9%
  
  [libx264 @ 0x7f9521030e00] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  0.1%  0.0%  0.0%  direct: 0.0%  skip:99.9%  L0:50.7% L1:49.3% BI: 0.0%
  
  [libx264 @ 0x7f9521030e00] 8x8 transform intra:59.1% inter:31.9%
  
  [libx264 @ 0x7f9521030e00] coded y,uvDC,uvAC intra: 21.4% 12.4% 7.4% inter: 0.0% 0.0% 0.0%
  
  [libx264 @ 0x7f9521030e00] i16 v,h,dc,p: 39% 30% 30%  0%
  
  [libx264 @ 0x7f9521030e00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 34% 47% 16%  1%  0%  0%  1%  0%  1%
  
  [libx264 @ 0x7f9521030e00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 20% 38% 15%  3%  3%  3%  6%  4%  7%
  
  [libx264 @ 0x7f9521030e00] i8c dc,h,v,p: 80% 15%  4%  1%
  
  [libx264 @ 0x7f9521030e00] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 0x7f9521030e00] ref P L0: 96.5%  1.2%  2.3%
  
  [libx264 @ 0x7f9521030e00] ref B L0: 51.5% 48.5%
  
  [libx264 @ 0x7f9521030e00] ref B L1: 99.6%  0.4%
  
  [libx264 @ 0x7f9521030e00] kb/s:11.97