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La conservation du net art au musée. Les stratégies à l’œuvre
26 mai 2011
Mis à jour : Juillet 2013
Langue : français
Type : Texte
Autres articles (68)
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Les autorisations surchargées par les plugins
27 avril 2010, parMediaspip core
autoriser_auteur_modifier() afin que les visiteurs soient capables de modifier leurs informations sur la page d’auteurs -
Le plugin : Podcasts.
14 juillet 2010, parLe problème du podcasting est à nouveau un problème révélateur de la normalisation des transports de données sur Internet.
Deux formats intéressants existent : Celui développé par Apple, très axé sur l’utilisation d’iTunes dont la SPEC est ici ; Le format "Media RSS Module" qui est plus "libre" notamment soutenu par Yahoo et le logiciel Miro ;
Types de fichiers supportés dans les flux
Le format d’Apple n’autorise que les formats suivants dans ses flux : .mp3 audio/mpeg .m4a audio/x-m4a .mp4 (...) -
Ajouter des informations spécifiques aux utilisateurs et autres modifications de comportement liées aux auteurs
12 avril 2011, parLa manière la plus simple d’ajouter des informations aux auteurs est d’installer le plugin Inscription3. Il permet également de modifier certains comportements liés aux utilisateurs (référez-vous à sa documentation pour plus d’informations).
Il est également possible d’ajouter des champs aux auteurs en installant les plugins champs extras 2 et Interface pour champs extras.
Sur d’autres sites (8159)
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Announcing the World’s Worst VP8 Encoder
5 octobre 2010, par Multimedia Mike — Outlandish Brainstorms, VP8I wanted to see if I could write an extremely basic VP8 encoder. It turned out to be one of the hardest endeavors I have ever attempted (and arguably one of the least successful).
Results
I started with the Big Buck Bunny title image :
And this is the best encoding that this experiment could yield :
Squint hard enough and you can totally make out the logo. Pretty silly effort, I know. It should also be noted that the resultant .webm file holding that single 400×225 image was 191324 bytes. When FFmpeg decoded it to a PNG, it was only 187200 bytes.
The Story
Remember my post about a naive SVQ1 encoder ? Long story short, I set out to do the same thing with VP8. (I wanted to the same thing with VP3/Theora for years. But take a good look at what it would entail to create even the most basic bitstream. As involved as VP8 may be, its bitstream is absolutely trivial compared to VP3/Theora.)
With the naive SVQ1 encoder, the goal was to create a minimally compliant SVQ1 encoded bitstream. For this exercise, I similarly hypothesized what it would take to create the most basic, syntactically correct VP8 bitstream with the least amount of effort. These are the overall steps I came up with :
- Intra-only
- Create a basic bitstream header that disables any extra features (no modification of default tables)
- Use a static quantizer
- Use intra 16×16 coding for each macroblock
- Use vertical prediction for the 16×16 intra coding
For coding each macroblock :
- Subtract vertical predictor from each row
- Perform forward transform on each 4×4 sub block
- Perform forward WHT on luma plane DCT coefficients
- Pack the coefficients into the bitstream via the Boolean encoder
It all sounds so simple. But, like I said in the SVQ1 post, it’s all very much like carefully bootstrapping a program to run on a particular CPU, and the VP8 decoder serves as the CPU. I’m confident that I have the bitstream encoding correct because, at the very least, the decoder agrees precisely with the encoder about the numbers represented by those 0s and 1s.
What’s Wrong ?
Compromises were made for the sake of getting some vaguely recognizable image encoded in a minimally valid manner. One big stumbling block is that I couldn’t seem to encode an end of block (EOB) condition correctly. I then realized that it’s perfectly valid to just encode a lot of zero coefficients rather than signaling EOB. An encoding travesty, I know, and likely one reason that the resulting filesize is so huge.More drama occurred when I hit my first block that had all zeros. There were complications in that situation that I couldn’t seem to avoid. So I forced the first AC coefficient to be 1 in that case. Hey, the decoder liked it.
As for the generally weird look of the decoded image, I’m thinking that could either be : A) an artifact of forcing 16×16 vertical prediction or ; or B) a mistake in the way that I transformed and predicted stuff before sending it to the decoder. The smart money is on a combination of both A and B.
Then again, as the SVQ1 experiment demonstrated, I shouldn’t expect extraordinary visual quality when setting the bar this low (i.e., just getting some bag of bits that doesn’t make the decoder barf).
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9 plugins you should definitely have heard of to prevent data leaks, security breaches and to get more flexibility in the way you log in to your Piwik.
9 janvier 2017, par InnoCraft — CommunityAt Piwik and at InnoCraft, we have always focussed on Security and take it very seriously. We were one of the first open source projects to offer a bug bounty for reporting security issues responsibly, Piwik has gone through several security audits and all changes in Piwik go through security reviews by our security experts.
On the Piwik Marketplace you will find some plugins that give you just that extra bit of additional security to keep your data even more secure and to let you secure how your users log in to your Piwik.
Security Info
This plugin provides security information about the server(s) your Piwik is running on and offers suggestions on how to improve the security settings of your servers. We highly recommend to install the Security Info plugin. Checks performed include for example usage of the latest PHP version, usage of latest Piwik version, usage of PHP ini settings like magic_quotes_gpc and more. More details & download
By Piwik
Google Authenticator
This plugins adds Two Factor Authentication, also known as 2FA, to Piwik. When logging in to Piwik, it forces you to confirm the identity by utilizing a combination of two different components. This means if someone knows your password, they will still need the other component in order to successfully log in, in this case a code that changes every minute on your phone. More details & download
By Stefan Giehl
Activity Log
The plugin gives you a detailed audit log of all activities that happen in your Piwik for better security and problem diagnostic. It provides documentary evidence of over 80 different activities that happen in your Piwik and lets you for example see when someone successfully logged in, when someone tried to log in with your username, when someone deleted data, and much more. More details
By InnoCraft, the makers of Piwik. Pricing starts from 39€ / $49 a year.
Login Revokable
This feature allows a user to log in from multiple locations (different browsers, computers, …) as usual and makes sure to log you out of all sessions as soon as you log out from any of these locations. More details & download
Force SSL
For security and privacy reasons you should always use Piwik over HTTPS (SSL). By activating this plugin, you make sure to redirect all “http://” requests to “https://” in the Piwik UI and API. More details & download
By InnoCraft, the makers of Piwik.
Performance Info
This plugin checks your Piwik configuration and compares it with some best practice settings. For example whether debug modes are disabled in a production environment, whether the example plugins that are shipped with Piwik are disabled, and more. Please note that this plugin works only with Piwik 2. More details & download
Login Ldap
Some companies might already manage their users in an LDAP server. This plugin allows you to log in to your Piwik via a central LDAP and supports web server authentication (eg. for Kerberos SSO). It authenticates with an LDAP server and uses LDAP information to personalize Piwik. More details & download
By Piwik
Login Shibboleth
Shibboleth is an open-source project that provides a Single Sign-On and allows websites to make informed authorization decisions in a privacy-preserving manner. Using this plugin allows you to connect to an existing Shibboleth environment so you need to manage users only once. More details & download
By Universität Würzburg Rechenzentrum
Login Http Auth
This plugin allows you to sign in to your Piwik using the HTTP Auth protocol instead of the standard login mechanism. It extends the standard Piwik authentication to use Basic HTTP Authentication. This may be useful if you use Basic HTTP Authentication already anyway and don’t want to manage your users additionally in Piwik itself. We recommend to use this only over SSL, for example with the Force SSL plugin. More details & download
By Piwik
Custom Development
Piwik is an analytics platform that you can extend and customize to your needs. Besides many configuration options you can change existing functionality and also build new functionality on top of Piwik, for example to log in to your Piwik via any Single-Sign-On. Read more about extending Piwik on the Piwik Developer Zone or get in touch with us and we take care of it for you.
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iOS 4.2+ security-related tweak : onfinish() -> playNext() fails if an unload() happens in-between. (Lesson : Don’t muck with .src, only one chance to set ?)
24 avril 2011, par Scott Schillerm demo/360-player/script/360player.js m demo/page-player/script/page-player.js iOS 4.2+ security-related tweak : onfinish() -> playNext() fails if an unload() happens in-between. (Lesson : Don’t muck with .src, only one chance to (...)