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• Evolution #2923 (Fermé) : Remplacement d’un document et date du document

  12 mai 2013, par cedric -

  si c’est la date du document que tu veux afficher (et pas sa date de publication) il faut simplement afficher
  [(#VAL{Y-m-d H:i:s}|date{#FICHIER|filemtime}|affdate)]
  Ça n’a pas vraiment de sens de stocker en base une date identique à celle du fichier sur le disque.

  Alternativement, la solution par plugin me semble le mieux, car cela correspond ici à un usage non générique de la date.

• Best logical formula to determine perceptual / "experienced" quality of a video, given resolution / fps and bitrate ?

  20 mars 2023, par JamesK

  I am looking for a formula that can provide me with a relatively decent approximation of a Video's playback quality that can be calculated based off of four metrics : width, height, fps, and bitrate (bits/sec). Alternatively, I can also use FFMPEG or similar tools to calculate a Video's playback quality, if any of those tools provide something like what I am looking for here.

  


  An example of what a Video might look like in my problem is as follows :

  


  interface Video {
  /** The width of the Video (in pixels). */
  width: number
  /** The height of the Video (in pixels). */
  height: number
  /** The frame rate of the Video (frames per second). */
  fps: number
  /** The bitrate of the video, in bits per second (e.g. 5_000_000 = 5Mbit/sec) */
  bitrate: number
}


  


  I came up with the following function to compute the average amount of bits available for any given pixel per second :

  


  const computeVideoQualityScalar = (video: Video): number => {
  // The amount of pixels pushed to the display, per frame.
  const pixelsPerFrame = video.width * video.height
  
  // The amount of pixels pushed to the display, per second.
  const pixelsPerSecond = pixelsPerFrame * video.fps
  
  // The average amount of bits used by each pixel, each second,
  // to convey all data relevant to that pixel (e.g. color data, etc)
  const bitsPerPixelPerSecond = video.bitrate / pixelsPerSecond
  
  return bitsPerPixelPerSecond
}


  


  While my formula does do a good job of providing a more-or-less "standardized" assessment of mathematical quality for any given video, it falls short when I try to use it to compare videos of different resolutions to one another. For example, a 1080p60fps video with a bitrate of 10Mbit/sec has a greater visual fidelity (at least, subjectively speaking, to my eyes) than a 720p30fps video with a bitrate of 9Mbit/sec, but my formula would score the 720p30fps video significantly higher than the 1080p60fps video because the 720p video has more bits available per pixel per second than the 1080p video.

  


  I am struggling to come up with ideas as to how to either come up with a different way to calculate the "subjective video quality" for a given video, or extend upon my existing idea here.

  


• Anomalie #3630 : Logo d’auteur et fonction de recherche de logo

  29 décembre 2015, par Debondt Didier

  Hello,

  Ce n’est pas de cela que je parle. Visiblement, j’ai mal exprimer le problème.

  Si j’utilise la fonction ainsi ’par exemple) :

  quete_logo( 'auteur' , 'on' , $id_auteur , null , flase)

  Cela ne va pas fonctionner car il faut faire :

  quete_logo( 'id_auteur' , 'on' , $id_auteur , null , flase )

  Il suffirai d’ajouter $type = id_table_objet($type) ; avant d’utiliser chercher_logo pour corriger le soucis.

  Tu vois le "problème" ?