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• How to introduce artificial noise in the videos using ffmpeg ?

  17 juin 2021, par ashish14

  I am trying to introduce artificial noise in the videos so as to simulate real-world behaviour. The sources of noise I am currently considering are :

  


  

  1. Quality of video

     

     • Modifying video properties such as frame rate, resolution, bit rate, codecs and compression.

     


     


  


  2. Recording Conditions

     

     • Factors such as lighting, brightness, contrast, darkness, blurriness, color etc.

     


     


  


  


  So far I have tried changing the brightness to replicate different lighting settings. I used this command
ffplay -vf eq=gamma=1.5:brightness=0.3:saturation=20 P2_Frontal_3_A.MP4 to change the values of brightness.

  


  Questions :

  


  

  • Does modifying the brightness like above make sense to simulate different lighting conditions ?

  


  • What other properties should I change for blurriness, contrast and darkness ?

  


  


• Use Video stream from Wifi device as input to stream over 4G

  1er mars 2017, par pbdev

  I’m building an Android app that streams video from a Wifi device to a Wowza server. It should be quite simple but I can’t figure out how to use both Wifi and 4G at the same time. The device I’m using is a Samsung S5 with Android 6.0.1. To sum it up, this is the goal :

  1. Fetch the video stream from a GoPro device over Wifi.
  2. Send the video stream to a Wowza server over 4G.

  When connected to the GoPro’s Wifi network I can ping the GoPro and see the stream in a MediaPlayer. Since I’m connected to a Wifi device that doesn’t provide internet access, I can’t ping my Wowza server. Once I’ve disabled Wifi this is no problem, by using FFmpeg I can reach the Wowza server over 4G.

  This is the FFmpeg command I want to use to copy the stream to the Wowza server, where 10.5.5.9 is the IP-address of the GoPro :

  ffmpeg -i http://10.5.5.9:8080/live/amba.m3u8 -acodec aac -ar 44100 -ab 48k -vcodec copy -f flv rtmp://username:password@my-wowza-server.com:1935/my-app/my-stream

  If I enable Wifi and connect to the GoPro, 10.5.5.9 is reachable but my-wowza-server.com isn’t. The Samsung S5 provides a Smart network switch which makes the Wowza server reachable but the connection to the GoPro gets lost.

  Is there any way to bind 10.5.5.9 to the Wifi interface of the phone and bind my-wowza-server.com to the cellular interface ?

• Presentation of Piwik’s collaborative translations platform : oTrance [Interview]

  19 avril 2013, par matt — Community, translation

  Piwik enables domain administrators, hobbyists, power users, personal website builders and everyone in between to access enormous amounts of data for website analytics. To support all those users, Piwik needs to be available in a number of different languages. From the start, we made internationalization (i18n) part of Piwik’s DNA. There are now dozens active volunteers who help make sure each language is well represented in the latest official release of Piwik. As of now, Piwik is available in 48 languages.

  Recently a new tool became available that makes the translation of Piwik much easier. The software we are using is an open source platform called oTrance. It has made our translation architecture more robust, and it allows us to expedite the timely delivery of high quality and up-to-date translations to the thousands of people who rely on Piwik every day.

  We’ve met with oTrance creator and lead developer Daniel Schlichtholz who answered a few questions for us.

  1. What is oTrance ?
  2. What sets oTrance apart from the other ways to manage translations ?
  3. Now that oTranCe 1.0 is out, what will you be working on next ?

  What is oTrance ?

  oTranCe is the short form of “Online Translation Center”. It was born because I needed a translation platform for my project MySQLDumper.

  Many languages have been added by the community and manual maintenance became more and more time consuming. I wanted to change that. So I searched for an existing platform I could use and tested a lot of approaches. To put a long story short : none of the given solutions satisfied my needs.

  From the view of a translator maintaining a language should be as easy as possible. In most cases they have to install a program on their local machine or the workflow was too difficult. A translator doesn’t want to struggle with technical things ; he just wants to translate the phrases and wants to know the progress.

  That’s the main goal we want to reach : to make the translation process as easy as possible.

  What sets oTrance apart from the other ways to manage translations ?

  Ease of use is one advantage of oTranCe compared to other solutions. Another advantage is that project administrators can install oTranCe on their own server – so nobody is dependant of a third party provider.

  We love to get feedback from other users. User feedback influences the way oTranCe is developed. We believe that this way oTranCe satisfies the requirements of the real world.

  We also have extensive user documentation, in our “Working with oTranCe” wiki. We try to document use cases in an understandable way. We don’t write down marketing buzz words, but try to explain the use from the view of the user/administrator.

  Now that oTranCe 1.0 is out, what will you be working on next ?

  The language files can be exported to version control and oTranCe can commit changes to the target repository. Currently we support export to Subversion, and we are working on a Git export adapter, which will be released soon.

  Another issue we are trying to solve is the context problem. When your project uses many different phrases the translator often doesn’t know in which context the current phrase is used. Version 1.1.0 (not released yet, but you can grab the latest developer version from GitHub) introduces the oTranCe-connector. The idea behind it : a small plug in grabs the used phrases/keys on the current page, and on click this list is submitted to oTranCe, where the translator can edit the words. This way the translator knows in which context these phrases are used. I wrote a small plug in for OXID eShop. Since it is really easy to implement, my hope is that other plug ins for other applications will be added by the community.

  Matthieu : Congratulations Daniel for having created such an awesome Translation Platform. At Piwik we are really thankful for oTranCe, which has resulted in much better translation process, and happier translators. Keep up the good work !

  If you are a Piwik user, and if you want to participate in translating Piwik, please sign up for an account on oTrance and become part of the team making Piwik available in more languages across the world.