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• Gallery of VP8 Encoding Naivete

  15 octobre 2010, par Multimedia Mike — VP8

  I’ve been toiling away as a multimedia technology generalist for so long that it’s easy for me to forget that not everyone is as versed in the minutiae of the domain as I am. But I recently experienced what it’s like to be such an outsider when I posted about my toy VP8 encoder, expressing that it’s one of the hardest things I have ever tried to do. I heard of from number of people who do have extensive experience in video encoding, particularly with the H.264 and VP8 codecs. Their reactions were predictable : What’s so hard ? Look, you might be a little too immersed in the area to really understand a relative beginner’s perspective.

  And to all the people who suggested that I should get the encoder into FFmpeg ASAP : Are you crazy ?! Did you see what the first pass of the encoder produced ? Do you have lower standards than even I do ?

  
  
  

  Not Giving Up
  I worked a little more on the toy encoder. Remember that the above image is what I’m hoping to encode somewhat faithfully for this experiment. In my first pass, I attempted vertical prediction for all planes. For my next pass, I forced the chroma planes to mid-level (which results in a greyscale image) and played with the 16×16 luma prediction modes. When implementing an extremely naive algorithm to decide which 16×16 prediction mode would be the best for a particular block, this is what the program produced :

  
  
  

  For fun, here is what the image encodes to when forcing various prediction modes :
  

  I think the DC-only prediction mode actually looks a little better than the image that the naive algorithm produced :

  
  
  

  Vertical 16×16 prediction, similar to the image from the last post (just in black and white) :
  

  
  
  

  Horizontal 16×16 prediction :
  

  
  
  

  This is the 16×16 prediction mode unique to VP8, the TrueMotion mode (based on On2/Duck’s very first video codec) :
  

  
  
  

  Wow, these encodings really bring down the cheerful tone of the original image.

  Next Steps
  I have little reason to believe that I am encoding and subsequently reconstructing the image correctly (i.e., error is likely propagating through the entire encoding). If I have time, the next step is to validate my reconstruction against the encoder. Then I need to get the entropy considerations correct so that I actually get some compression out of this format.

• Official Piwik Training in Berlin – 2014, June 6th

  6 mai 2014, par Piwik Core Team — Community

  This event will focus on providing training to users of the Piwik analytics platform. The training will provide attendees with the necessary skills and knowledge that they will need to be able to take their website to the next level with Piwik.

  Language : English

  Register to Piwik Training now.

  Location : The 25hours Hotel Bikini Berlin is as diverse as the big city it is located in and as wild as a jungle. The hotel showcases cosmopolitan Berlin at its location in the listed Bikini-Haus building between the Tiergarten park and Breitscheidplatz with Kaiser Wilhelm Memorial Church.

  

  Why do you need training ?

  If you have just started using Piwik and are finding it a bit overwhelming, this training event will benefit you immensely. You will be able to learn all the necessary skills that will allow you move forward with Piwik.

  For users who have been using Piwik for a short time and have a bit of experience in using Piwik, you will be able to learn how to advance your skills and extend your knowledge of the Piwik platform.

  Advanced users will be able to gain more knowledge about the complex features and functions that Piwik incorporates, allowing you to customise different areas of the platform and learn about advanced topics.

  How can you benefit from this training event ?

  By understanding how Piwik works and how to use and operate Piwik more effectively, you will be able to make sound changes to your website that will allow you to achieve your business goals.

  Everyone, from ecommerce businesses to government organisations can benefit from this training event and learn the essential skills and gain the relevant knowledge to meet their goals and requirements.

  Some of the skills that you will learn during the training include :

  • How to install and get started with the Piwik platform
  • How Piwik will add value to your website
  • How to analyse and make sense of the data and information that you collect
  • How to create custom segments that will allow you to report on certain data and information
  • Advance exercises – Piwik settings, tweaking and basic diagnostics

  What equipment do I need in order to participate in the event ?

  You will need a computer that is able to connect to a Wifi network

  Are the tickets transferable ?

  Yes, the tickets are transferable.

  What is the refund policy on the tickets ?

  You are entitled to a refund up to 1 week before the commencement of the training.

  Training details

  <script type="text/javascript">          (function() { var scribd = document.createElement("script"); scribd.type = "text/javascript"; scribd.async = true; scribd.src = "#{root_url}javascripts/embed_code/inject.js"; var s = document.getElementsByTagName("script")[0]; s.parentNode.insertBefore(scribd, s); })()        </script>

  Contact us : contact@piwik.pro

  Registrations

  Register to Piwik Training now !

• Official Piwik Training in Berlin – 2014, June 6th

  6 mai 2014, par Piwik Core Team — Community

  This event will focus on providing training to users of the Piwik analytics platform. The training will provide attendees with the necessary skills and knowledge that they will need to be able to take their website to the next level with Piwik.

  Language : English

  Register to Piwik Training now.

  Location : The 25hours Hotel Bikini Berlin is as diverse as the big city it is located in and as wild as a jungle. The hotel showcases cosmopolitan Berlin at its location in the listed Bikini-Haus building between the Tiergarten park and Breitscheidplatz with Kaiser Wilhelm Memorial Church.

  

  Why do you need training ?

  If you have just started using Piwik and are finding it a bit overwhelming, this training event will benefit you immensely. You will be able to learn all the necessary skills that will allow you move forward with Piwik.

  For users who have been using Piwik for a short time and have a bit of experience in using Piwik, you will be able to learn how to advance your skills and extend your knowledge of the Piwik platform.

  Advanced users will be able to gain more knowledge about the complex features and functions that Piwik incorporates, allowing you to customise different areas of the platform and learn about advanced topics.

  How can you benefit from this training event ?

  By understanding how Piwik works and how to use and operate Piwik more effectively, you will be able to make sound changes to your website that will allow you to achieve your business goals.

  Everyone, from ecommerce businesses to government organisations can benefit from this training event and learn the essential skills and gain the relevant knowledge to meet their goals and requirements.

  Some of the skills that you will learn during the training include :

  • How to install and get started with the Piwik platform
  • How Piwik will add value to your website
  • How to analyse and make sense of the data and information that you collect
  • How to create custom segments that will allow you to report on certain data and information
  • Advance exercises – Piwik settings, tweaking and basic diagnostics

  What equipment do I need in order to participate in the event ?

  You will need a computer that is able to connect to a Wifi network

  Are the tickets transferable ?

  Yes, the tickets are transferable.

  What is the refund policy on the tickets ?

  You are entitled to a refund up to 1 week before the commencement of the training.

  Training details

  <script type="text/javascript">          (function() { var scribd = document.createElement("script"); scribd.type = "text/javascript"; scribd.async = true; scribd.src = "#{root_url}javascripts/embed_code/inject.js"; var s = document.getElementsByTagName("script")[0]; s.parentNode.insertBefore(scribd, s); })()        </script>

  Contact us : contact@piwik.pro

  Registrations

  Register to Piwik Training now !