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• Correct Complex Lens Distortion in FFMPEG (or OpenCV) [closed]

  29 septembre 2024, par C.M.

  I need to process videos which were taken with a wide angle vehicle camera. A good example is this frame from a video :

  


  

  


  As you can see, the image is pretty distorted and I need to correct that. After some research, neither a Barrel distortion or a Pincushion distortion is the case here. I'd say it depends on the axis. The x axis seems to have a Pincushion distortion, but the y axis seems to have a Barrel distortion.

  


  In my project I use a Java backend and I use FFmpeg to process the videos (re-encoding, color correction, ...). Therefore I'd like to do this in FFmpeg as another video filter.

  


  I tried to use the lenscorrection filter but couldn't find any suitable values for k1 and k2. IMHO this isn't even possible since the filter can only handle the two types of distortion mentioned above. Here are two examples where I tried to correct the horizontal and vertical elements of the image :

  


  

  


  (with k1= -0.7, k2=0.4)

  


  

  


  (with k1=0.7)

  


  But the resulting image would need to look like this (just roughly edited with GIMP) :

  


  

  


  Is this even possible with FFmpeg filters ? I already tried out the v360 filter (similar like in this article) but just achieved similar results.

  


  If I'm correct this isn't possible with video filters. So I thought of doing this in OpenCV in Java by extracting all the frames with FFmpeg, transforming them with OpenCV and rendering them to a video again. Unfortunately I have no experience with OpenCV and couldn't get any results. I think this should be possible in some way.

  


  Can someone help me ?

  


• The Ultimate Guide to HeatMap Software

  20 septembre 2021, par Ben Erskine — Analytics Tips, Plugins, Heatmaps

  One of the most effective ways to improve the user experience on your website is to use heatmap software. As well as in-depth insight on how to improve your website and funnels, user behaviour analytics complement traditional web metrics with insights from your customers’ point of view. 

  Heatmap software shows actual user behaviour. That means that you have a visual representation of why a customer might not be converting instead of guessing. 

  By tracking clicks, mouse movement, and page scrolling as well as analysing above the fold content engagement and overall session recordings, heatmap software helps improve user experience and therefore customer retention and conversions.  

  

  What is heatmap software ?

  Heatmap software is a data visualisation tool that uses colour to show what actions a user is taking on a website. 

  If there is a design element on a page that many users engage with, it will show as red/hot. For elements that are less engaging, it will show on the analysis as blue/cold. 

   

  Heatmap software like Matomo helps businesses to improve user experience and increase conversions by tracking elements such as :

  • Flow through sales funnels 
  • Individual session recordings for user experience 
  • A/B page comparisons 
  • Form analytics for sign ups and conversions 
  • Media interaction such as instruction or sales videos
  • Clicks on important links and information 

  Using data visualisation software like a heatmap provides more in-depth data when combined with standard website metrics. 

  What is heatmap software used for ?

  Heatmap software tracks website user behaviour to improve website performance and increase conversions. 

  Heatmaps can show you a detailed analysis of : 

  • Where visitors are clicking (or not clicking) 
  • Where visitors are hovering with their mouse
  • How far users are scrolling or stopping 
  • Where the focus is above the fold 
  • What roadblocks or frictions customers are facing in the sales funnel

  Analysing activity on your website and across channels from your customers point of view is critical in developing a customer-centric business model. 

  This is because heatmaps not only show you what customers are doing but why they are doing it. 

  Heatmap software is ideal for businesses updating and redesigning websites. It also helps to answer important growth questions such as “how can we improve our user experience ?” and “why is our sales funnel not converting better ?”. 

  The benefits of using data visualisation like heatmaps for your website

  Heatmaps are critical for improving websites because they drastically improve customer experience. 

  Customer experience is one of the most important factors in modern business success. A Walker study found that customer experience is one of the biggest differentiators between brands, overtaking other factors such as price. 

  Where straightforward website metrics show customers left a page without action, data visualisation and session recordings show what happens in between them arriving and leaving. This gives web developers and marketers invaluable insights to improve website design and ultimately increase conversions. 

  How heatmap software improves your website and conversions

  There are a few key ways that heatmap software boosts website performance and conversions. All of them focus on both creating a seamless buyer journey and using data to improve results over time. 

  How heatmap software improves conversions ; 

  • By improving UX and usability– 70% of online businesses fail due to bad usability. Heatmaps identify user frustrations and optimise accordingly 
  • By improving content structure – Heatmaps take the guesswork out of design layout and content structure by showing real visitor experiences on your website 
  • By comparing A/B landing pages – Using heatmaps on alternate landing pages can show you why conversions are working or not working based on user activity on the page
  • By optimising across devices – See how your visitors are interacting with your content to learn how well optimised your website is for various devices and remove roadblocks 

  Heatmap analytics you need to improve website user experience

  Click heatmap

  Click heatmaps are useful for two key reasons.

  Firstly, it shows where website users are clicking. 

  Heatmaps that show clicks give you a visual representation of whether copy and CTA links are clear from the customers’ point of view. It can also show whether a customer is clicking on a design feature that doesn’t link anywhere. 

  Secondly, it shows where website users are not clicking. This is just as important when developing funnels and improving user experiences.

  For example, you may have a CTA button for a free trial or purchase. A click heatmap analysis would show if this isn’t clicked on mobile devices and informs developers that it needs to be more mobile-friendly.

  

  Mouse move or hover heatmap

  Like a click heatmap, a mouse hover heatmap shows how you can improve the overall user experience.

  For example, hover heatmaps identify where your visitors engage on a particular webpage. Ideally, of course, you want them to engage with CTAs. Analysing their mouse movements or where they are hovering for more information gives you an indication of any page elements that are distracting them or not working.

  

  Scroll heatmap

  A scroll heatmap uses colours to visualise how far down in a page your visitors scroll. For most web pages, the top will have the most impressions and will naturally get less views (i.e. get “colder” on the heatmap) further down the page. 

  This lets you find out if there is important content positioned too far down the page or if the page is designed to encourage users to keep scrolling.

  No matter how good your product or service is, it won’t convert if potential customers aren’t engaged and scrolling far enough to see it.

  

  Above the fold analysis 

  Above the fold is the content that a visitor sees without scrolling. 

  In a heatmap, the “Average Above the Fold” line will show you how much content your visitors see on average when they open your page. It also shows whether the page design is engaging, whether it encourages visitors to keep scrolling, and whether important information is too far down the page and therefore being missed. 

  Above the fold analysis is arguably the most important as this is the section that the highest number of traffic will see. Using this information ensures that the right content for conversion is seen by the highest number of visitors. 

  

  Session recording

  Session Recording lets you record a real visitor session, so you can see clicks, mouse movements, scrolls, window resizes, page changes, and form interactions all in one. 

  They allow you to understand the experience from the point of view of your visitor and then optimise your website to maximise your success.

  Heatmap software like Matomo takes this one step further and allows you to gather session recordings for individual segments. By analysing sessions based on segments, you can further personalise and optimise based on customer history and patterns.

  

  Final thoughts on heatmap software 

  Heatmap software improves your user experience by easily spotting critical issues that you can then address. 

  As well as that, heatmap analytics like clicks, mouse movement, scroll, above the fold analysis and session recordings increase your marketing ROI by making the most of your existing traffic. 

  It’s a win-win ! 

  Now that you know what heatmap software is, the benefits of using heatmaps on your website and how it can improve your user experience, check out more handy resources.

  10 Proven Ways Heatmaps Improve Website Conversions

  How to use Behavioural Analytics to Improve Website Performance

  Heatmap Overview Video

  Session Recording Overview Video

• ffmpeg - conflicting libraries or unable to compile C++ project [duplicate]

  2 octobre 2020, par QRrabbit

  This is less about C++, and more about specific compiling avcodec and avformat as those are used inside FFmpeg. I'm trying to compile for the first time newly downloaded ffmpeg source. All the linking has been resolved, and the program errors on this specific allocation.

  


  I'm writing my first program - attempt at avformat libraries inside my C++ code. Linker errors on this line :

  


  [ 89%] Linking CXX executable ffmpeg_01
clang: error: no such file or directory: 'VideoToolbox'
clang: error: no such file or directory: 'CoreFoundation'
clang: error: no such file or directory: 'CoreMedia'
clang: error: no such file or directory: 'CoreVideo'
clang: error: no such file or directory: 'CoreServices'
clang: error: no such file or directory: 'OpenGL'
clang: error: no such file or directory: 'CoreImage'
clang: error: no such file or directory: 'AppKit'
clang: error: no such file or directory: 'Foundation'
clang: error: no such file or directory: 'CoreAudio'
clang: error: no such file or directory: 'AVFoundation'
clang: error: no such file or directory: 'CoreGraphics'
make[3]: *** [ffmpeg_01] Error 1


  


  This is the content of my *libavcodec.pc file, and it has an entry of conflicts : which lists all of the items that clang cannot find, I don't know if those are linked somehow. I found a source pointing that similar error appears if I had other forks of ffmpeg, but I do not.

  


  prefix=/usr/local
exec_prefix=${prefix}
libdir=/usr/local/lib
includedir=/usr/local/include

Name: libavcodec
Description: FFmpeg codec library
Version: 58.108.100
Requires: libswresample >= 3.8.100, libavutil >= 56.60.100
Requires.private: 
Conflicts:
Libs: -L${libdir}  -lavcodec -liconv -lm -llzma -lz -framework AudioToolbox -L/usr/local/Cellar/x264/r3011/lib -lx264 -pthread -framework VideoToolbox -framework CoreFoundation -framework CoreMedia -framework CoreVideo -framework CoreServices
Libs.private: 
Cflags: -I${includedir}


  


  I don't have experience in cmakefile, I can paste it here if needed.
Any help is greatly appreciated, because I'm stuck for the past several days.