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• Metal Gear Solid VP3 Easter Egg

  4 août 2011, par Multimedia Mike — Game Hacking

  Metal Gear Solid : The Twin Snakes for the Nintendo GameCube is very heavy on the cutscenes. Most of them are animated in real-time but there are a bunch of clips — normally of a more photo-realistic nature — that the developers needed to compress using a conventional video codec. What did they decide to use for this task ? On2 VP3 (forerunner of Theora) in a custom transport format. This is only the second game I have seen in the wild that uses pure On2 VP3 (first was a horse game). Reimar and I sorted out most of the details sometime ago. I sat down today and wrote a FFmpeg / Libav demuxer for the format, mostly to prove to myself that I still could.

  Things went pretty smoothly. We suspected that there was an integer field that indicated the frame rate, but 18 fps is a bit strange. I kept fixating on a header field that read 0x41F00000. Where have I seen that number before ? Oh, of course — it’s the number 30.0 expressed as an IEEE 32-bit float. The 4XM format pulled the same trick.

  Hexadecimal Easter Egg
  I know I finished the game years ago but I really can’t recall any of the clips present in the samples directory. The file mgs1-60.vp3 contains a computer screen granting the player access and illustrates this with a hexdump. It looks something like this :

  
  
  

  Funny, there are only 22 bytes on a line when there should be 32 according to the offsets. But, leave it to me to try to figure out what the file type is, regardless. I squinted and copied the first 22 bytes into a file :

   1F 8B 08 00   85 E2 17 38   00 03 EC 3A   0D 78 54 D5
   38 00 03 EC   3A 0D
  

  And the answer to the big question :

  $ file mgsfile
  mgsfile : gzip compressed data, from Unix, last modified : Wed Oct 27 22:43:33 1999
  

  A gzip’d file from 1999. I don’t know why I find this stuff so interesting, but I do. I guess it’s no more and less strange than writing playback systems like this.

• Trouble with the ffmpeg -ss flag when capturing one frame from a Macbook iSight webcam

  31 août 2011, par Andy

  For about five years I've used ffmpeg in a shell script to grab one frame from my linux'd-up Macbook's iSight :

  ffmpeg -f video4linux2 -s 640x480 -r 15 -i /dev/video0 -an -vframes 1 -vcodec mjpeg -y -sameq -ss 1.5 snapshot.jpg

  I just upgraded my Ubuntu distro from Lucid to Natty (ffmpeg ver. 0.6.2-4:0.6.2-1ubuntu1).
  Now that syntax turns the iSight on but hangs indefinitely.

  [output snipped, ending with:]
  
  frame=    0 fps=  0 q=0.0 Lsize=      -0kB time=10000000000.00 bitrate=  -0.0kbits/s    
  
  video:0kB audio:0kB global headers:0kB muxing overhead -inf%

  Without the '-ss' flag it seems to successfully grab the first frame and exit immediately - the only difference in output being :

  frame=    1 fps=  0 q=0.0 Lsize=      -0kB time=0.07 bitrate=  -2.6kbits/s    
  
  video:16kB audio:0kB global headers:0kB muxing overhead -100.132730%

  However, the '-ss 1.5' was necessary to delay the frame capture by 1.5 seconds to allow the cam sufficient time to adjust the exposure.

  The -itsoffset flag seemed promising, but doesn't seem to change ffmpeg's behavior (ie doesn't hang, but no delay).

  Any ideas ?

• 12 ways Matomo Analytics helps you to protect your visitor’s privacy

  5 mai 2020, par InnoCraft — Analytics Tips, Privacy, Security

  This post was originally published on January 11, 2017, and updated on May, 2020.

  At Matomo we think privacy matters. From the beginning, Matomo has had a strong focus on privacy and ensuring the privacy of your visitors and analytics data. 

  Here are some ways how you can ensure your users and visitors privacy by using Matomo (Piwik).

  1. Owning the data gives you power to protect user privacy

  Whether you host Matomo on-premises yourself, or whether you use Matomo’s cloud, YOU keep control of your data and nobody else. By knowing exactly where your data is stored and having full control over what happens to it, you have the power to protect your user’s privacy. No-one else can claim ownership. 

  2. GDPR compliance

  GDPR is one of the most important privacy laws to have come out in the last few years. As such, Matomo takes GDPR compliance very seriously. There’s even a 12-step checklist for you to follow to ensure your Matomo is GDPR compliant. Not only that Matomo is HIPAA, CCPA, LGPD, and PECR compliant.

  3. Data anonymization

  For better privacy by default, Matomo implements a range of data anonymization techniques. One of the main techniques is not recording the full IP address of your visitors. Some countries even require you to anonymize additional info considered Personally Identifiable Information (PII).

  To change the IP anonymization settings go to “Administration > Privacy”. 

  

  4. Configuring Matomo to not process personal data or personally identifiable information (PII)

  To further protect the privacy of your visitors, you can learn how to not process any personal information or PII. 

  5. Deleting old visitor logs

  The is important because visitor logs contain information all the collected raw data about every visitor and every action. You can configure Matomo to automatically delete logs from the database. When you delete old logs, only the real time and visitor log reports will no longer work for this old time period, all other aggregated reports will still work.

  For privacy reasons, we highly recommend that you keep the detailed Matomo logs for only 3 to 6 months and delete older log data. This has one other nice side effect : it will free significant database space, which will, in turn, slightly increase performance !

  

  6. Supporting the Do Not Track preference

  Do Not Track enables users to opt out of any tracking by websites they do not visit, including analytics services, advertising networks, and social platforms. By default, Matomo respects users preference and will not track visitors which have specified “I do not want to be tracked” in their web browsers. Get more information about DoNotTrack.

  To make sure Do Not Track is respected, go to “Administration => Privacy”.

  7. Including an Opt-Out Feature on your website or app

  By embedding the Opt-Out feature in your website, you give your visitors the possibility to opt-out of the tracking. When you go to “Administration > Privacy”, you will be able to copy and paste an HTML Iframe code to embed the opt-out feature for example into your privacy policy page or in your ‘Legal’ page. Your users can then click on a link to opt-out.

  On the Matomo Marketplace there are also some plugins available to customize the Opt-Out experience. For example AjaxOptOut and CustomOptOut.

  

  8. Disabling Live features

  The Real-Time, Visitor Log and Visitor Profile features give you insights into the tracked raw data by showing you details about every visitor and every action they performed. To protect the privacy of your visitors you may decide to prevent access to such features by disabling the “Live” plugin in “Administration => Plugins”. This way only aggregated reports will be shown in your Matomo.

  9. Disabling fingerprinting across websites

  By default, when one of your visitors visits several of your websites, Matomo will create a fingerprint for this user that will be different across the websites to increase the visitors’ privacy. You can make sure that this feature is disabled by going to “Administration => Config file” and verifying that the value of “enable_fingerprinting_across_websites” is set to zero.

  10. Disabling tracking cookies

  Matomo uses first-party cookies to store some information about visitors between visits. In some countries, the legislation requires websites to provide a way for users to opt-out of all tracking, in particular tracking cookies. You can disable cookies by adding one line in the Matomo Javascript code.

  11. Creating the tool of your dreams by developing your own plugins and getting access to the API

  Matomo is an open platform that lets you extend and customise the tracking ; reporting ; and user interface to your needs and to protect your visitors’ privacy the way you want or need it. Learn more in the Matomo Developer Zone. You may also have a look at our Matomo Marketplace where you can find several free and premium features to extend your Matomo.

  12. Transparency

  By default, all information and all collected data in your Matomo server are protected and nobody can access it. However, Matomo allows you to optionally make your collected data public and you can export any Matomo report including the whole dashboard to embed it into your website. This way you can show your users exactly which information you track. When you decide to make reports public, we do our best to protect privacy and automatically hide any Personally Identifiable Information such as the Visitor Profile and we make sure to not show any Visitor IP address and the Visitor ID.

  Bonus tip – A privacy policy template for you

  When you use Matomo to track your visitors, we recommend you update your Privacy Policy to explain how Matomo is used and what data it gathers. Here’s a Privacy Policy template for you to copy on your site.

  Continuous privacy improvements

  We are always interested in improving the privacy. If you miss any feature or have an idea on how to improve the privacy, please let us know.

  More information about all the Matomo features

  If you want to learn more about all the features in Matomo, have a look at our User Guides and FAQ entries.