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• FFMPEG decoding video produces discolored YUV frame

  13 mai 2019, par Jeff Gong

  I am using FFMPEG directly to decode a single video frame encoded in H.264 from a test video I’m running using the following command :

  ffmpeg -i test.mp4 -ss 00:00:00 -vframes 1 -pix_fmt yuv420 output.yuv

  For some reason, when I open the file on a YUV viewer, I can distinctly tell that the colors are slightly off compared to the original input. I’ve tried to play with the colorspace and color matrix options, but nothing I do seems to replicate exactly the original colors.

  For example, I’ve also tried the following commands :

  ffmpeg -i test.mp4 -ss 00:00:00 -vframes 1 -pix_fmt yuv420p -vf colormatrix=bt470:bt709 output.yuv

  and

  ffmpeg -i test.mp4 -ss 00:00:00 -vframes 1 -pix_fmt yuv420p -color_primaries bt709 -color_trc linear -colorspace bt709 output.yuv

• PHP Sort Order Process Codeiginiter

  5 août 2017, par Alan El-nino Malmsteen

  i use php codeigniter to manage video using FFMPEG, but i dont know how to delete original video after convertion successful.

  if(!($_FILES["upload_video"]["type"] == "video/mp4"))
  
      {
  
      $prename = $r.'.'.$ext;
  
      $video = $prename.'.mp4';
  
      $directory_path  = "/home/templates/videos/".$prename;
  
      $directory_path_full = "/home/templates/videos/".$prename;
  
      exec("ffmpeg -i ".$directory_path_full." ".$directory_path.".mp4"); 
  
  
  
      // Delete original format video
  
      $this->load->helper("file");
  
      unlink($directory_path_full); 
  
  
  
      }else{
  
      $video = $r.'.'.$ext;
  
      }

  When i use "unlink" it work good to delete file, but the video is corrupt (maybe php directly delete it when converting progress)
  So, can you help me to create sort order php process for this case ?

• ffmpeg-python multiple outputs at different resolutions

  3 janvier 2021, par Darius Mandres

  I am using ffmpeg-python to convert .mp4 files to HLS streamable formats. Currently I can get it to work at full resolution using this piece of code

  


  video = ffmpeg.input(file_path)
output = ffmpeg.output(
  video,
  filename=f"{base_path}{uuid}.m3u8",
  format="hls",
  start_number=0,
  hls_time=10,
  hls_list_size=0
)

output.run()


  


  If the original video is 1920x1080 the resulting .ts files will be of the same resolution. What do I have to do to get multiple resolutions ? Say 360p 480p, 720p ?

  


  And how does ffmpeg handle a resolution when the original is smaller ? Say I try to convert a 480p video to a resolution of 720p ?