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• Announcing our latest open source project : DeviceDetector

  30 juillet 2014, par Stefan Giehl — Community, Development, Meta, DeviceDetector

  This blog post is an announcement for our latest open source project release : DeviceDetector ! The Universal Device Detection library will parse any User Agent and detect the browser, operating system, device used (desktop, tablet, mobile, tv, cars, console, etc.), brand and model.

  Read on to learn more about this exciting release.

  Why did we create DeviceDetector ?

  Our previous library UserAgentParser only had the possibility to detect operating systems and browsers. But as more and more traffic is coming from mobile devices like smartphones and tablets it is getting more and more important to know which devices are used by the websites visitors.

  To ensure that the device detection within Piwik will gain the required attention, so it will be as accurate as possible, we decided to move that part of Piwik into a separate project, that we will maintain separately. As an own project we hope the DeviceDetector will gain a better visibility as well as a better support by and for the community !

  DeviceDetector is hosted on GitHub at piwik/device-detector. It is also available as composer package through Packagist.

  How DeviceDetector works

  Every client requesting data from a webserver identifies itself by sending a so-called User-Agent within the request to the server. Those User Agents might contain several information such as :

  • client name and version (clients can be browsers or other software like feed readers, media players, apps,…)
  • operating system name and version
  • device identifier, which can be used to detect the brand and model.

  For Example :

  Mozilla/5.0 (Linux; Android 4.4.2; Nexus 5 Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/32.0.1700.99 Mobile Safari/537.36

  This User Agent contains following information :

  Operating system is Android 4.4.2, client uses the browser Chrome Mobile 32.0.1700.99 and the device is a Google Nexus 5 smartphone.

  What DeviceDetector currently detects

  DeviceDetector is able to detect bots, like search engines, feed fetchers, site monitors and so on, five different client types, including around 100 browsers, 15 feed readers, some media players, personal information managers (like mail clients) and mobile apps using the AFNetworking framework, around 80 operating systems and nine different device types (smartphones, tablets, feature phones, consoles, tvs, car browsers, cameras, smart displays and desktop devices) from over 180 brands.

  Note : Piwik itself currently does not use the full feature set of DeviceDetector. Client detection is currently not implemented in Piwik (only detected browsers are reported, other clients are marked as Unknown). Client detection will be implemented into Piwik in the future, follow #5413 to stay updated.

  Performance of DeviceDetector

  Our detections are currently handled by an enormous number of regexes, that are defined in several .YML Files. As parsing these .YML files is a bit slow, DeviceDetector is able to cache the parsed .YML Files. By default DeviceDetector uses a static cache, which means that everything is cached in static variables. As that only improves speed for many detections within one process, there are also adapters to cache in files or memcache for speeding up detections across requests.

  How can users help contribute to DeviceDetector ?

  Submit your devices that are not detected yet

  If you own a device, that is currently not correctly detected by the DeviceDetector, please create a issue on GitHub
  In order to check if your device is detected correctly by the DeviceDetector go to your Piwik server, click on ‘Settings’ link, then click on ‘Device Detection’ under the Diagnostic menu. If the data does not match, please copy the displayed User Agent and use that and your device data to create a ticket.

  Submit a list of your User Agents

  In order to create new detections or improve the existing ones, it is necessary for us to have lists of User Agents. If you have a website used by mostly non desktop devices it would be useful if you send a list of the User Agents that visited your website. To do so you need access to your access logs. The following command will extract the User Agents :

  zcat ~/path/to/access/logs* | awk -F'"' '{print $6}' | sort | uniq -c | sort -rn | head -n20000 > /home/piwik/top-user-agents.txt

  If you want to help us with those data, please get in touch at devicedetector@piwik.org

  Submit improvements on GitHub

  As DeviceDetector is free/libre library, we invite you to help us improving the detections as well as the code. Please feel free to create tickets and pull requests on Github.

  What’s the next big thing for DeviceDetector ?

  Please check out the list of issues in device-detector issue tracker.

  We hope the community will answer our call for help. Together, we can build DeviceDetector as the most powerful device detection library !

  Happy Device Detection,

• Lost video when converting from MKV to MP4 with FFMPEG

  25 décembre 2022, par Francesco Virga

  I'm trying to come up with a robust script to handle all MKV -> MP4 video conversions.

  


  The classic example I've found is ffmpeg -i input.mkv -codec copy output.mp4. This works for most videos, but I find that the video stream gets lost for certain videos. Using -map 0 doesn't help, the examples I'm using only have one video stream and one audio stream.

  


  If I only copy the audio codec, it seems to work fine, but takes much longer since video is re-encoded. For this I'm use ffmpeg -i input.mkv -c:a copy output.mp4. I'm fine to use this for certain videos, but am not sure how to determine whether video re-encoding is needed or not (since I want to avoid it when possible).

  


  Here's the output I get when I run the first command and lose video :

  


  % ffmpeg -i input.mkv -codec copy output.mp4

ffmpeg version N-103075-g4c694093be-tessus  https://evermeet.cx/ffmpeg/  Copyright (c) 2000-2021 the FFmpeg developers
  built with Apple clang version 11.0.0 (clang-1100.0.33.17)
  configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libmysofa --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvmaf --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-libzmq --enable-libzvbi --enable-version3 --pkg-config-flags=--static --disable-ffplay
  libavutil      57.  2.100 / 57.  2.100
  libavcodec     59.  3.102 / 59.  3.102
  libavformat    59.  4.101 / 59.  4.101
  libavdevice    59.  0.100 / 59.  0.100
  libavfilter     8.  1.103 /  8.  1.103
  libswscale      6.  0.100 /  6.  0.100
  libswresample   4.  0.100 /  4.  0.100
  libpostproc    56.  0.100 / 56.  0.100
Input #0, matroska,webm, from 'input.mkv':
  Metadata:
    CREATION_TIME   :
    ENCODER         : Lavf55.12.0
  Duration: 00:59:15.97, start: 0.062000, bitrate: 1892 kb/s
  Stream #0:0: Video: hevc (Main), yuv420p(tv, bt709), 1912x1072 [SAR 1:1 DAR 239:134], 23.98 fps, 23.98 tbr, 1k tbn (default)
  Stream #0:1(eng): Audio: aac (LC), 48000 Hz, 5.1, fltp (default)
    Metadata:
      title           : Surround
      LANGUAGE        : eng
  Stream #0:2(eng): Subtitle: ass (default)
  Stream #0:3(eng): Subtitle: ass
Output #0, mp4, to 'output.mp4':
  Metadata:
    encoder         : Lavf59.4.101
  Stream #0:0: Video: hevc (Main) (hev1 / 0x31766568), yuv420p(tv, bt709), 1912x1072 [SAR 1:1 DAR 239:134], q=2-31, 23.98 fps, 23.98 tbr, 16k tbn (default)
  Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp (default)
    Metadata:
      title           : Surround
      LANGUAGE        : eng
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame=32634 fps=0.0 q=-1.0 size=  295424kB time=00:22:41.04 bitrate=1778.1kbits/s speed=2.72e+03x frame=63776 fps=63775 q=-1.0 size=  611840kB time=00:44:19.94 bitrate=1884.3kbits/s speed=2.66e+03frame=85256 fps=62686 q=-1.0 Lsize=  822207kB time=00:59:15.83 bitrate=1894.2kbits/s speed=2.61e+03x
video:736136kB audio:83404kB subtitle:0kB other streams:0kB global headers:1kB muxing overhead: 0.325361%


  


• G.I. Joe Custom Multimedia

  30 mars 2012, par Multimedia Mike — General

  I received this 3-disc set of G.I. Joe CD-ROMs today :

  
  
  

  Copyright 2003, and labeled as PC ONLY. Each disc claims to have 2 episodes. So are these some sort of video discs ? Any gaming elements ? I dove in to investigate.

  So, it turns out that there are some games on these discs, done in Flash Player (which tells me that these were probably available on the web at some point). Here’s a shooting gallery game from the first disc :

  
  
  

  As promised by the CD-ROM copy, the menu does grant access to 2 classic G.I. Joe episodes. Selecting either one launches this :

  
  
  

  Powered by C-ezy ? Am I interpreting that correctly ? Anyway, the video player goes fullscreen and looks fine (given the source material). I can’t capture screenshots and controls are limited to : space for pause, ESC to exit player, and up/down to control volume. No seeking and certainly no onscreen controls. Pretty awful player.

  Studying the first disc, I find a 550 MB file with the name 5859Hasbro.egm. Coupled with ep58.cfg and ep59.cfg files in the same directory, I gather that the disc has G.I. Joe episodes 58 and 59 (though the exact episodes, “There’s No Place Like Springfield” parts 1 and 2, are listed on Wikipedia as being episodes 154 and 155 ; but who’s counting ?). The cfg files contain this text :

  ep58.cfg :
  EGM_GIJOE.exe
  5859Hasbro.egm /noend /track:0 /singletrack
  ep59.cfg :
  
  EGM_GIJOE.exe
  
  5859Hasbro.egm /noend /track:1 /singletrack
  

  The big EGM file starts with the string “Egenie Player”. After that, I see absolutely no clues. The supporting EGM_GIJOE.exe file has some interesting strings : “Decore Bits Per Pixel” (I know I have seen “Decore” used to mean “decoding core” in some libraries), “Egenie Player – %s, Version :%s”, “4th June 2002″, a list of common FourCC tags seen in AVI files, “Brought to you by Martin, Patrick Bob and Bren” (do you suppose “Patrick Bob” is one person’s name ?), a list of command line options…

  Aha ! A URL : http:\www.e-genie.tv (yep, backslashes, not forward slashes). e-genie.tv seems to redirect to mygenie.tv, which… doesn’t appear to be strictly related to video technology these days.