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• ffmpeg drop frames on purpose to lower filesize

  20 octobre 2014, par max

  Our security system records and archives our IP cameras streams with ffmpeg -use_wallclock_as_timestamps 1 -i rtsp://192.168.x.x:554/mpeg4 -c copy -t 60 my_input_video.avi

  I run it with crontab every minute so it creates videos of 60 seconds ( 15Mb) for each camera every minute. When an intrusion occurs, the camera sends a picture through FTP and a script called by incrontab :

  1- forwards immediately the picture by email

  2- selects the video covering the minute the intrusion occured, compress it with h264 (to 2,6Mb) and sends it by email

  It is working really well but if a thief crosses the path of various cameras, the connection to the SMTP server is not fast enough so video emails are delayed. I’d like to compress the videos even more to avoid that. I could lower the resolution (640x480 to 320x240 for example) but sometimes 640x480 is handy to zoom on something which looks to be moving...

  So my idea is to drop frames in the video in order to lower the filesize. I don’t care if the thief is walking like a "stop motion Lego" on the video, the most important is I know there is someone so I can act.

  mediainfo my_input_video.avi says Frame rate = 600.000 fps but it is of course wrong. FPS sent by IP cameras are always false because it varies with the network quality ; this is why i use "-use_wallclock_as_timestamps 1" in my command to record the streams.

  with ffmpeg -i  my_input_video.avi -vcodec h264 -preset ultrafast -crf 28 -acodec mp3 -q:a 5 -r 8 output.avi the video is OK but filesize is higher (3Mb)

  with ffmpeg -i  my_input_video.avi -vcodec h264 -preset ultrafast -crf 28 -acodec mp3 -q:a 5 -r 2 output.avi the filesize is lower (2,2Mb) but the video doesn’t work (it is blocked at the first frame).

  Creating a mjpeg video (mjpeg = not interlaced frames) in the middle of the process (first exporting to mjpeg with less frames and then exporting to h264) creates same results.

  Do you know how I can get my thief to walk like a "stop motion Lego" to lower the filesize to a minimum ?

  Thanks for any help

• Generating test data – Introducing the Piwik Platform

  9 octobre 2014, par Thomas Steur — Development

  This is the next post of our blog series where we introduce the capabilities of the Piwik platform (our previous post was How to create a command). This time you’ll learn how to generate test data.

  Developers are developing on their local Piwik instance which usually does not contain useful data compared to a real Piwik installation in production (only a few test visits and a few tests users and websites). The ‘VisitorGenerator’ plugin lets you generate any number of visits, websites, users, goals and more. The generator makes sure there will be data for each report so you can easily test anything.

  Getting started

  In this series of posts, we assume that you have already installed Piwik. If not, visit the Piwik Developer Zone where you’ll find the Installation guide for developers.

  Installing the VisitorGenerator plugin

  The easiest way to install the plugin is by using the Marketplace in Piwik itself. It is accessible via Settings => Marketplace => Get new functionality. There you’ll find the plugin “VisitorGenerator” which you can install and activate in one click.

  If your Piwik instance is not connected to the internet you can download the plugin from the VisitorGenerator page on the Marketplace. Afterwards you can install the plugin by going to Settings => Marketplace => Uploading a plugin and uploading the previously downloaded ZIP file.

  If you have already installed the plugin make sure it is activated by going to Settings => Plugins.

  Generating websites

  After you have installed the plugin you can add as many websites as you need. This is useful for instance when you want to test something that affects many websites such as the ‘All Websites’ dashboard or the Websites manager. To generate any number of websites use the following command :

  ./console visitorgenerator:generate-website --limit=10

  This will generate 10 websites. If you need more websites simply specify a higher limit. In case you are wondering the names and URLs of the websites are randomly generated by the Faker PHP library.

  Generating goals

  In case you want to test anything related to Goals you should execute the following command :

  ./console visitorgenerator:generate-goals --idsite=1

  This will generate a few goals for the specified site. The generated goals are defined in a way to make sure there will be conversions when generating the visits in the next step.

  Generating visits

  To generate visits there are two possibilities. Either via the Piwik UI by going to Settings => Visitor Generator or by using the command line. The UI is a bit limited in generating visits so we recommend to use the command line. There you can generate visits as follows :

  ./console visitorgenerator:generate-visits --idsite=1

  This will generate many different visits for the current day. Don’t worry if it takes a while, it will insert quite a few visits by default.

  In case you want to generate visits for multiple days in the past as well you can specify the --days option.

  ./console visitorgenerator:generate-visits --idsite=1 --days=5

  Providing your own logs

  Half of the generated visits are randomly generated and half of the visits are based on real logs to make sure there is data for each report. If you want to generate visits based on your own logs for a more realistic testing just place your log files in the plugins/VisitorGenerator/data folder and make sure the file name ends with .log. You can find a few examples in the VisitorGenerator data folder.

  To generate visits based only on real log files then use the --no-fake option.

  ./console visitorgenerator:generate-visits --idsite=1 --no-fake

  All generated visits will come from the logs and no random visits nor random fake data will be used.

  Advanced features

  We are regularly adding new commands, tools and runtime checks to make your life as a developer easier. For instance you can also generate users and annotations. In the future we want to extend the plugin to create visits in the background to make sure there will be constantly new actions in the real time report.

  Are you missing any kind of generator or any other feature to make your life as a developer easier ? Let us know by email, we are listening !

  Would you like to know more about the Piwik platform ? Go to our Piwik Developer Zone where you’ll find guides and references on how to develop plugin and themes.

• Anomalie #3722 (Nouveau) : le pré-remplissage du champ auteur du formulaire_ecrire_auteur se retro...

  29 février 2016, par Pascal Rigaux

  Le code squelettes-dist/formulaires/ecrire_auteur.php pré-remplit le champ "email_message_auteur" à $GLOBALS[’visiteur_session’][’email’] .

  Avec un modèle du genre :

  #FORMULAIRE_ECRIRE_AUTEUR
  

  utilisé dans une page, le pré-remplissage se retrouve mis en cache.

  Solutions de contournement : éviter de re-calculer la page, ou vider le cache.
  En supprimant le pré-remplissage, le problème disparait...