Recherche avancée

Sur d’autres sites (8189)

• Révision 18055 : optimiser SQLite :

  14 juin 2011, par cedric -

  reformatage des requetes en compilant les regexp et en evitant un preg_replace_callback couteux

  requete en evitant de compter les lignes tant qu’on en a pas besoin en PDO : on note le link et la requete a compter, et on ne le fait qu’a la premiere demande de spip_sqlite_count

  sql_fetch : (...)

• ffmpeg encoding a video with time_base Not equal to framerate does not work in HML5 video players

  1er juillet 2019, par Gilgamesh22

  I have a time_base of 90000 with a frame rate of 30. I can generate a h264 video and have it work in VLC but this video does not work in the browser player. If I change the time_base to 30 It works fine.

  Note : I am changing the frame->pts appropriately to match the time_base.
  Note : Video does not have audio stream

  //header.h
  
  AVCodecContext *cctx;
  
  AVStream* stream;

  Here is the non working example code

  //source.cpp
  
  stream->time_base = { 1, 90000 };
  
  stream->r_frame_rate = { fps, 1 };
  
  stream->avg_frame_rate = { fps, 1 };
  
  
  
  cctx->codec_id = codecId;
  
  cctx->time_base = { 1 ,  90000 };
  
  cctx->framerate = { fps, 1 };
  
  
  
  // ...... 
  
  // add frame code later on timestamp are in millisecond
  
  frame->pts = (timestamp - startTimeStamp)* 90;

  Here is the working example code

  //source.cpp
  
  stream->time_base = { 1, fps};
  
  stream->r_frame_rate = { fps, 1 };
  
  stream->avg_frame_rate = { fps, 1 };
  
  
  
  cctx->codec_id = codecId;
  
  cctx->time_base = { 1 ,  fps};
  
  cctx->framerate = { fps, 1 };
  
  
  
  // ...... 
  
  //  add frame code timestamp are in millisecond
  
  frame->pts = (timestamp - startTimeStamp)/(1000/fps);

  Any ideas on why the second example works and the first does not in the HTML5 video player.

• Convert Videos with FFMPEG to PowerPoint 2016 compatible video format [closed]

  11 septembre 2020, par Sebastian S.

  I am trying to convert a bunch of videos to a video format that is natively supported by PowerPoint 2013/2016 on a Windows 7 system.

  


  Microsoft recommends on their website mp4 with h264 and aac.

  


  Video and audio file formats supported in PowerPoint

  


  


  In PowerPoint 2013 and later, and in PowerPoint 2016 for Mac, for the best video playback experience, we recommend that you use .mp4 files encoded with H.264 video (a.k.a. MPEG-4 AVC) and AAC audio. In PowerPoint 2010, we recommend that you use .wmv files.

  


  


  


  We recommend using .m4a files encoded with AAC audio. In PowerPoint 2010, we recommend that you use .wav or .wma files.

  


  


  Audio is not important for me.
I tried to convert my videos with ffmpeg using the following options :

  


  ffmpeg -i Input.avi -c:v libx264 -preset slow -crf 22 -c:a copy Output.mp4


  


  However I cannot import the video to PowerPoint 2016 (32 or 64bit, I tried both). I always get a missing codec error.

  


  PPT Error when including video files

  


  Has anyone successfully encoded videos to a natively supported PowerPoint video format (on Windows) ?