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• Is there a way to non-linear speed-up video with ffmpeg ?

  3 mars 2020, par leoossa

  I’ve seen thousands of websites suggesting using setpts to speedup video

  ffmpeg -i input.mp4 -filter:v "setpts=0.5*PTS" output.mp4

  The thing is - I don’t want to speed-up video in a linear way. I want it to accelerate. So I want ’acceleration’ (Wiki) to be constant and ’speed’ to be growing.

  From what I’ve seen on ffmpeg docs setpts can be an equation, I tried to play with PREV_OUTPTS but with no success.
  Is it even possible to achieve that with ffmpeg ?

• Anomalie #3456 (Nouveau) : bug sur |liens_absolus

  26 mai 2015, par Fil Up

  La fonction des liens absolus recherche bêtement src=… sur tout le contenu de la balise img, ce qui fait que si on a un data-original-src="xxxx", il ne trouve pas le src= et rate sa cible.

  Proposition de patch :

  ```
  // ne s’applique qu’aux textes contenant des liens
  // http://doc.spip.org/@liens_absolus
  function liens_absolus($texte, $base=’’)
  - if (preg_match_all(’,(<(a|link|image):space :+[^<>]*href=["\’] ?)([^"\’ ><[:space :]]+)([^<>]*>),imsS’,
  + if (preg_match_all(’,(<(a|link|image|img|script)\s[^<>]*(href|src)=[^<>]*>),imsS’,
  $texte, $liens, PREG_SET_ORDER))
  foreach ($liens as $lien)
  - $abs = url_absolue($lien<sup>3</sup>, $base) ;
  - if ($abs <> $lien<sup>3</sup> and !preg_match(’/^#/’,$lien<sup>3</sup>))
  - $texte = str_replace($lien<sup>0</sup>, $lien<sup>1</sup>.$abs.$lien<sup>4</sup>, $texte) ;
  + foreach(array(’href’, ’src’) as $attr)
  + $href = extraire_attribut($lien<sup>0</sup>, $attr) ;
  + if (strlen($href)>0)
  + $abs = url_absolue($href, $base) ;
  + if ($href != $abs and !preg_match(’/^#/’,$href))
  + $texte = inserer_attribut($texte, $attr, $abs) ;
  +
  +
  +
  
  
  - if (preg_match_all(’,(<(img|script):space :+[^<>]*src=["\’] ?)([^"\’ ><[:space :]]+)([^<>]*>),imsS’,
  - $texte, $liens, PREG_SET_ORDER))
  - foreach ($liens as $lien)
  - $abs = url_absolue($lien<sup>3</sup>, $base) ;
  - if ($abs <> $lien<sup>3</sup>)
  - $texte = str_replace($lien<sup>0</sup>, $lien<sup>1</sup>.$abs.$lien<sup>4</sup>, $texte) ;
  -
  -
  +
  return $texte ;
  
  ```

• How to stream video using C/C++

  19 janvier 2015, par Arif Ali Saiyed

  I want to stream video to a file/ or memory buffer using VC++ on windows.
  Can anyone suggest easy to integrate library ?(that has one H,one LIB and one DLL).

  I am exploring the libVLC right now and gonna explore FFMPEG also.
  dont want to spend time in building these complex software fully myself, would appreciate any help/pointer/ references.

  ---

  My ultimate goal is to stream a video and consume the stream on HTML5 viewer.
  I tried streaming using VLC media player and streamed to a OGG file, I used same OGG file in a HTML5-Video tag and it worked.

  Now I want to do the streaming part using libVLC instead of VLC media player.
  I want to stream the video file to File or memory stream.

  I have found this sample https://wiki.videolan.org/Stream_to_memory_(smem)_tutorial/

  BUt unsure of how to get started ?
  1) Where do i get the libVLC.dll, libVLC.lib, libVLC.h , Is there any sample visual studio that has everything setup and I can straight begin to write the code using libVLC etc.

  2) Since libVLC is said to depdend on 200+ other libraries/modules/plugins, what will I have include and distribute with my application ?
  http://www.enjoythearchitecture.com/vlc-architecture.html
  https://wiki.videolan.org/Contrib_Status/

  3) streaming format : above example seems to stream into PCM format, cant I get it stream in some format that has better codec and regonized by HTML5 ? For example when i tried using VLC media player , my options were as following
  :sout=#transcodevcodec=theo,vb=800,acodec=vorb,ab=128,channels=2,samplerate=44100:filedst=C :\Users\testUser\stream-output.ogg,no-overwrite :sout-keep