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• FFMpeg is writing a matplotlib animation with diminishing quality

  3 mars 2017, par Bryan Stafford

  I am trying to create a bunch of animations that follow the paths National Hockey League teams travel during the current season. Currently, my animation looks like this.

  As you can see, the animation begins decently sharp but within 2 seconds the quality bottoms out and everything is grainy.

  The relevant code is this :

  ani = animation.FuncAnimation(fig, update, frames=len(all_x + 20), 
  
                                interval=75, repeat=False)
  
  filepath =  map_team + '.mp4'
  
  ani.save(filepath, writer='ffmpeg', fps=30)
  
  plt.tight_layout()
  
  plt.show()

  I have chosen FFMpeg as my writer because I hope to put about 30 graphics online and the MP4 format keeps each file around 1.5MB. If there’s a way to keep the graphics sharp, with low file sizes, and able to be uploaded onto Imgur, I would love to do that with my project.

  Thanks.

• FFmpeg parameters for Fisheye image correction

  19 janvier 2023, par Julio Cesar

  I am trying to achieve two things (any of them will work for my solution) :

  


  

  1. Fisheye video to equirectangular (and view it in 360 view)

  


  2. Fisheye video to flat (if I understood correctly, it will be just like the fisheye image (maybe I will lose some FoV ?) but without distortions. Of course in this case I will not use 360 view).

  


  


  Camera specs : https://documentation.meraki.com/MV/Viewing_Video/Understanding_Image_Quality_on_the_MV32

  


  For test purposes I am using an image as input :

  


  For 1), I am using ffmpeg -i input_file -vf v360=fisheye:e:ih_fov=180:iv_fov=180:pitch=90 output_file. This command gives me a rectangular image where the half upper is black, and when testing in https://renderstuff.com/tools/360-panorama-web-viewer/ the user can navigate through this black space (I would like to limit user view, so he could not get to the black part). If I crop and remove the black part, the image in the 360 view becomes distorted (loses the aspect ratio).

  


  For 2), I tried ffmpeg -i input_file -vf v360=fisheye:flat:ih_fov=180:iv_fov=180 output_file but it doesn't seem to correct the distortions properly.

  


  FYI this video will be published in AntMedia server to be used as an iframe in web applications. I'll try to use 1) in AntMedia since it supports 360 view (https://antmedia.io/play-live-360-degree-video/).

  


  Since I am new to this, please ask for more information if needed.
  
Thanks in advance.

  


• Revision 3c092e2474 : Merge changes Ibb308526,I99e330f8 * changes : Prevent CR in screen mode from r

  11 septembre 2015, par Alex Converse

  Merge changes Ibb308526,I99e330f8

  * changes :
  Prevent CR in screen mode from refreshing flat inter blocks forever.
  For screen content consider intra uv when color_sensitivity is set.