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• Generate VTT pixel flat image with coordinates

  27 novembre 2022, par Alex Malin

  I have a question.

  


  I want to know if they have any options to create webVTT horizontal images with FFmpeg
like an attached image tack one pixel/two every second and create one horizontal image with coordinates.

  


  Thank you.

  


  

  


  WEBVTT 


  


  00:00.000 —> 00:08.000
/assets/thumbnails-01.jpg#xywh=0,0,160,90

  


  00:09.000 —> 00:16.000
/assets/thumbnails-01.jpg#xywh=160,0,320,90

  


• look for a specific filetype in a directory in php and send it to a different directory after conversion

  12 juin 2019, par flash

  I have a directory in which there is a mp4 file (including other files as well) which I want to convert into mp3 and then send it to different directory. I have used the following command line command to covert into mp3 and its working perfectly fine.

  ffmpeg -i 36031P.mp4 -map 0:2 -ac 1 floor_english.mp3 

  mp4 file is inside in_folder. Using ffmpeg, I want to convert mp4 file into mp3 and send it to out_folder.

  <?php
  
  $dir    = 'in_folder';
  
  $files1 = scandir($dir);
  
  print_r($files1);    /* It lists all the files in a directory including mp4 file*/
  
  ?>

  print_r($files1) lists all the file in a directory including mp4file.

  Problem Statement :

  I am wondering what php code I need to write so that it looks for only mp4 file inside the directory and send it to different directory (let say out_folder) after converting into mp3.

  The pictorial representation of what I want :

  

• ffmpeg 180 degree panoramic fisheye image to equirectangular / flat

  7 juillet 2024, par Willy62

  I am trying to get my Hikvision Panovu image of a sportsfield to look like a standard camera image, similar to what would be seen with a Veo solution / traditional camera.

  


  This is what the image would ideally look like with a little bit of zoom. Note the players are all upright and it looks "correct" and not skewed with the far end of the field in line with the horizon.

  


  veo sample image

  


  The original image looks like this (same field but other side). This is a 180 degree panoramic image from a Hikvision camera as found here.

  


  It provides the following output natively.

  


  hikvision native view

  


  I have had some luck converting the image with ffmpeg using the v360 filter. Note there is a downward tilt meaning I have to apply some yaw to correct it.

  


  v360=input=fisheye:output=rectilinear:ih_fov=180:iv_fov=87.5:d_fov=87.5:pitch=20:yaw=5:w=3840:h=2160


  


  And this gets the following output :

  


  deskewed v360 image

  


  So the challenge here to make the original image flat/equirect but to address the skew such that :

  


  

  • the players are orientated "upright"

  


  • the far sideline of the field looks like a straight line in line with the horizon

  


  • the image quality is preserved as best as possible

  


  


  With these cameras the image is 32MP so there is the opportunity to do an ePTZ into the area of interest.

  


  I suspect v360 isnt the right choice here and it is some remap-style filter, or perhaps I am best going across to gstreamer or similar.

  


  I tried an ffmpeg v360 filter and it partially works, but the players are still skewed because the top of the image is not wide enough. The issue can possibly be solved by correctly applying a couplex perspective filter, but I think this will only mask the issue and perspective requires a complex filter that hasn't worked for me so far.