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• Debugging Video Frame Differences

  14 mai 2014, par jvenema

  I’m trying to decode an h264-encoded video frame using a decoder that has fairly limited capabilities (Broadway JS).

  Here’s the process I’m using for testing :

  1. Encode single image using h264 (output is 62KB) using OpenH264 from Cisco, write to disk
  2. Read file as binary in JS (loaded via XHR)
  3. Decode in JS using Broadway
  4. Display in canvas

  I actually have a functional example of this, but there’s a manual step at the moment between steps 1 and 2 - I have to call FFMPEG to force a small translation, and I can’t figure out why.

  I have successfully integrated Cisco’s Openh264 library into my project, and can encode the image as h264 and write it to disk. I’ve confirmed the encoding itself is valid by using FFMPEG to extract the frame back out as a JPEG (looks perfect).

  But, to make the frame decode properly in JS, I have to do a conversion using FFMPEG. It does some magic, the file size drops to 58KB, and voila, everything starts working.

  The Openh264 libraries only work with the baseline configuration, so I’m assuming I have some other random parameter set incorrectly. Problem is, if I use ffprobe to compare the frames - the settings are identical ! But the file sizes are different, so obviously something is different.

  So now the final question - what tool can I use to truly see what FFMPEG is doing behind the scenes here to make my "manually" encoded frame work ? Is there a tool that will let me compare all the details of two h264 frames ?

• Piwik and Piwik PRO featured in VentureBeat Insight as “an obvious solution” for web analytics

  7 avril 2015, par Piwik Core Team — About

  We are proud to see Piwik and Piwik PRO featured in the recent report published by VentureBeat Insight. Published at the end of March 2015, Conversion Rate Optimisation : how to win at performance marketing was based on surveys of almost 3000 CRO tools users.

  

  Piwik earned a perfect score of 100 out of 100 for website analytics and was featured as an “obvious solution” for those who prefer to use open source products. The report also pointed out a very low abandonment rate of Piwik by its users, despite its growing popularity (3%).

  You can preview the “Conversion Rate Optimisation : how to win at performance marketing” report for free here
  (Note : there is a form to fill in before you can access it).

  View other awards won by Piwik here.

• Piwik and Piwik PRO featured in VentureBeat Insight as “an obvious solution” for web analytics

  7 avril 2015, par Piwik Core Team — About

  We are proud to see Piwik and Piwik PRO featured in the recent report published by VentureBeat Insight. Published at the end of March 2015, Conversion Rate Optimisation : how to win at performance marketing was based on surveys of almost 3000 CRO tools users.

  

  Piwik earned a perfect score of 100 out of 100 for website analytics and was featured as an “obvious solution” for those who prefer to use open source products. The report also pointed out a very low abandonment rate of Piwik by its users, despite its growing popularity (3%).

  You can preview the “Conversion Rate Optimisation : how to win at performance marketing” report for free here
  (Note : there is a form to fill in before you can access it).

  View other awards won by Piwik here.