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• Giving Thanks For VP8

  25 novembre 2010, par Multimedia Mike — VP8

  It’s the Thanksgiving holiday here in the United States. I guess that’s as good a reason as any to release a first cut of my VP8 encoder. In order to remind people that they shouldn’t expect phenomenal quality from it — and to discourage inexperienced people from trying to create useful videos with it — I have hardcoded the quantizers to their maximum settings. For those not skilled in the art, this is the setting that yields maximum compression and worst quality. When compressing the Big Buck Bunny logo image, the resulting file is only 2839 bytes but observe the reconstructed quality :

  
  
  It really just looks like a particularly stormy day in the forest.
  

  First VP8 File From An Independent Encoder
  I found a happy medium on the quantizer scale and encoded the first 30 seconds of Big Buck Bunny for your inspection. I guess this makes it the first VP8/WebM file from an independent encoder (using FFmpeg’s Matroska muxer as well).

  Download : bbb-360p-30sec-q40.webm ( 13 MBytes)

  I think the quality makes it look like it was digitized from an old VHS tape.

  For fun, here’s the version with the quantizer cranked to the max : bbb-360p-30sec-q127.webm ( 1.3 MBytes)

  Aside : I was going to encapsulate the video in this post using a bare HTML5 <video> tag for the benefit of the small browsing population who could view that (indeed, it works fine in Chrome). But that would be insane due to the fact that supporting browsers preload the video with no easy (read : without the help of JavaScript) method for overriding this unacceptable default.

  The Code
  I’m still trying to get over my fear of git. To that end, I have posted the code on Github :

  https://github.com/multimediamike/ffvp8enc

  I still don’t like you, git. But I’m sure we’ll find some way to make this work.

  Other required code changes in the basic FFmpeg tree :

  • Of course, copy vp8enc.c into libavcodec/
  • In libavcodec/allcodecs.c, ’REGISTER_DECODER (VP8, vp8);’ turns into ’REGISTER_ENCDEC (VP8, vp8);’
  • Add ’OBJS-$(CONFIG_VP8_ENCODER) += vp8enc.o’ to libavcodec/Makefile

  Further Work
  About the limitations and work yet to do :

  • it’s still intra-only, no interframes (which is where a lot of compression occurs)
  • no rate control or distortion optimization, obviously
  • no intra 4x4 coding (that’s close to working but didn’t my little T-day deadline)
  • no quantization control ; this should really be hooked up to the FFmpeg command line but I’m not sure how
  • encoder writes into a static-sized, 1/2 MB memory buffer ; this can overflow
  • code is a mess (what did you expect at this stage of the game ?)
  • lots and lots of other things, surely

• Help us Reset The Net today on June 5th

  5 juin 2014, par Piwik Core Team — Community, Meta

  This blog post explains why the Piwik project is joining ResetTheNet online protest and how you can help make a difference against mass surveillance. It also includes an infographic and links to useful resources which may be of interest to you.

  Snowden revelations, a year ago today

  On June 5, 2013 the Guardian newspaper published the first of Edward Snowden’s astounding revelations. It was the first of a continuous stream of stories that pointed out what we’ve suspected for a long time : that the world’s digital communications are being continuously spied upon by nation states with precious little oversight.

  Unfortunately, mass surveillance is affecting the internet heavily. The Internet is a powerful force that can promote democracy, innovation, and creativity, but it’s being subverted as a tool for government spying. That is why Piwik has decided to join Reset The Net.

  June 5, 2014 marks a new year : a year that will not just be about listening to the inside story of mass surveillance, but a new year of fighting back !

  How do I protect myself and others ?

  Reset the Net is asking everyone to help by installing free software tools that are designed to protect your privacy on a computer or a mobile device.

  Reset the Net is also calling on websites and developers to add surveillance resistant features such as HTTPS and forward secrecy.

  Participate in ResetTheNet online protest

  Have you got your own website, blog or tumblr ? Maybe you can show the Internet Defense League’s “Cat Signal !” on your website.Get the code now to run the Reset the Net splash screen or banner to help make privacy viral on June 5th.

  Message from Edward Snowden

  Evan from FFTF sent us this message from Edward Snowden and we thought we would share it with you :

  One year ago, we learned that the internet is under surveillance, and our activities are being monitored to create permanent records of our private lives — no matter how innocent or ordinary those lives might be.

  Today, we can begin the work of effectively shutting down the collection of our online communications, even if the US Congress fails to do the same. That’s why I’m asking you to join me on June 5th for Reset the Net, when people and companies all over the world will come together to implement the technological solutions that can put an end to the mass surveillance programs of any government. This is the beginning of a moment where we the people begin to protect our universal human rights with the laws of nature rather than the laws of nations.

  We have the technology, and adopting encryption is the first effective step that everyone can take to end mass surveillance. That’s why I am excited for Reset the Net — it will mark the moment when we turn political expression into practical action, and protect ourselves on a large scale.

  Join us on June 5th, and don’t ask for your privacy. Take it back.

  – Message by Edward Snowden

  ResetTheNet privacy pack infographic

  

  Additional Resources

  Configure Piwik for Security and Privacy

  • Turn on automatic SSL redirection in your Piwik.
  • Configure Piwik for advanced Privacy.
  • Best security practises for Piwik.

  More info

  • Learn why this matters (EFF)
  • Data Privacy Day – Why is privacy important ? (Piwik)
  • Web Analytics Privacy (Piwik)

• Is -vfilter not available on Debian 5 ?

  3 octobre 2011, par Kor

  I'm getting problems trying to make my website (done in PHP) work online.
  At a specific time, I need to upload a video and convert it, also scaling its dimensions. I use a call like this one :

  ffmpeg -y -i '/path/to/video.mp4' -f flv -ab 56 -ar 22050 -r 20 -vfilter "scale=704:-1" '/path/to/new/video.flv'

  It works offline on my computer (Ubuntu 10.10), but it doesn't do the same online (Debian Lenny 5.0). The response I get from the server is :

  [Mon Oct 03 15:48:56 2011] [error] [client 81.184.6.124] /servers/path/to/ffmpeg: unrecognized option '-vfilter'

  I have also tried with '-vf', but it just doesn't work at all. So my question is, am I doing it wrong, or is it that Debian unables video filters for some reason ?

  I give you some info about this server :

  Debian 5.0
  
  PHP: 5.2.6
  
  FFmpeg r11872+debian_0.svn20080206-18+lenny1
  
  libavutil   3212800
  
  libavcodec  3355136
  
  libavformat 3409664
  
  libavdevice 3407872

  EDIT : Oh my, I just saw it. No libavfilter installed. I'll tell you what their support tells me in a couple hours.