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• Extremely slow ffmpeg/sws_scale() - only on heavy duty

  28 septembre 2020, par user2328447

  I am writing a video player using ffmpeg (Windows only, Visual Studio 2015, 64 bit compile).
With common videos (up to 4K @ 30FPS), it works pretty good. But with my maximum target - 4K @ 60FPS, it fails. Decoding still is fast enough, but when it comes to YUV/BGRA conversion it is simply not fast enough, even though it's done in 16 threads (one thread per frame on a 16/32 core machine).

  



  So as a first countermeasure I skipped the conversion of some frames and got a stable frame rate of 40 that way. Comparing the two versions in Concurrency Visualizer, I found a strange issue I don't know the reason of.

  



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  Here's an image of the frameskip version :

You see that the conversion is pretty quick (average roughly 35ms)
Thus, as multiple threads are used, it also should be quick enough for 60FPS, but it isn't !

  



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  The image of the non-frameskip version shows why :

The conversion of a single frame has become ten times slower than before (average roughly 350ms). Now a heavy workload on many cores would of course cause a minor slowdown per core due to reduced turbo - let's say 10 or 20%. But never an extreme slowdown of 1000%.

  



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  Interesting detail is, that the stack trace of the non-frameskip version shows some system activity I don't really understand - beginning with ntoskrnl.exe!KiPageFault+0x373. There are no exceptions, other error messages or such - it just becomes extremely slow.

  



  Edit : A colleague just told me that this looks like a memory problem with paged-out memory at first glance - but my memory utilization is low (below 1GB, and more than 20GB free)

  



  Can anyone tell me what could be causing this ?

  


• Make MP4 video using JPEG 2000 frames and ROI

  21 mars 2012, par Leandro

  I'm having a hard time trying to figure out how to solve the following problem.

  I have a set of jp2 frames. I want to save them as a .mp4 video for archiving (which is great because it supports motion compensation) and then be able to extract the frames as jp2 files again.

  I have this working with a set of tools/libraries like ffmpeg. The issue is that I also want to include a ROI in the original jp2 images.

  When I do that, the video shows nothing where the ROI originally was, and when I use ffmpeg to go back to the original files, the frames are still broken.

  I tried going from JPEG2000 w\ ROI to another format before making the mp4 file, but every tool I use seems to have the same results : the ROI gets translated as a square w/o nothing there.

  Any help would be greatly appreciated.

  Thanks !

• New Matomo Mobile 2.4.0 released

  12 janvier 2018, par Matomo Core Team

  New Matomo Mobile 2.4.0 update is now available for Android 6+ and iOS10.3+ devices. This is the first mobile release that shows signs of the new Matomo branding instead of Piwik. Don’t be surprised if the app still shows the Piwik app icon. This is on purpose as the name of the app changed to Matomo Mobile and some users would otherwise not find the app anymore if they haven’t heard of the renaming from Piwik to Matomo before.

  What’s new in Matomo Mobile ?

  This new version brings some bug fixes and improvements to our Android and iOS apps :

  • Piwik is now Matomo which includes some name changes in the app as well as showing the new logo
  • Fixed broken “Get-involved” link
  • Links to Matomo or other websites now open in the browser app and no longer in the app itself
  • Improved visitor log to support more actions (see #12284)
  • We have updated the underlying framework bringing some performance and compatibility improvements

  Download the Apps

  Update now or install either the iOS version or the Android version. Android users can also download the latest version from our website : download Matomo Mobile 2.4.0 from our website.

  If you experience any issues with this version please let us know.

  Sponsor

  The new Matomo Mobile release has been sponsored by InnoCraft, the creators of Matomo.

  

  Happy analytics on the go,

  The post New Matomo Mobile 2.4.0 released appeared first on Analytics Platform - Matomo.