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• Why do file length appears to be longer after using ffmpeg convert HEIC to PNG ?

  15 octobre 2024, par BrinyFish

  I have been moving all my photos from iphone to my windows PC. Because I don't like to keep all the files in HEIC format, so I used ffmpeg to try to batch convert all the photos from HEIC to PNG.

  


  Get-ChildItem *.heic | ForEach-Object {
    ffmpeg -i $_.FullName -map_metadata 0 -q:v 1 "$($_.BaseName).png"
}


  


  File size difference
After testing this chatGPT generated code on a small sample set of photos, I realize that the length of the PNG photos are smaller than the length of the HEIC photos. I have always believed that HEIC is the compressed format, which should be smaller. However, this size difference really makes me wonder if I am losing resultion or meta data. Do anyone know why would this be the case ?

  


  I have googled and most articles are saying that HEIC should be smaller than PNG, which don't help me in this case.

  


• ffmpeg : combine portrait and landscape video files in one file by adding a black frame

  18 juillet 2021, par Oliver

  i use my iPhone to record videos. Usually i get a lot of short clips, which I upload to my pc and then concatenate them with ffmpeg using this command :

  


  ffmpeg -f concat -safe 0 -i filelist.txt -c:v libx265 -preset slow -x265-params strong-intra-smoothing=0:merange=58 -crf 25 -c:a aac -b:a 320k -tag:v hvc1 output.mp4


  


  filelist contains a list of these clips sorted by date. This works fine, but recently a had some clips recorded in portrait mode. The result was an output video which contained the portrait clips stretched to fill the full horizontal space. Instead of that i would like to just have the horizontal space filled with black borders. Is that possible by changing the command posted above ? Or do i have to convert those portrait clips before ?

  


• Video rotation with FFmpeg

  6 mars 2016, par haresh

  I’m developing a PHP web service for my iPhone app in order for the users to upload videos. When users want to see a video on the site they get a horizontal video, so I need rotate the video using FFmpeg commands. Can someone help me ?

  function make_rotation($input, $output, $transpose="1") {
  
      $ffmpegpath = "ffmpeg";
  
      if(!file_exists($input)) return false;  
  
      //$command = "$ffmpegpath -i $input -vf 'transpose=$transpose' $output";
  
      //$command = "ffmpeg -vfilters 'rotate=270' -i $input $output";
  
      $command ="ffmpeg -i $input -vf 'transpose=$transpose'  $output";
  
      exec($command);
  
      return true;
  
  }

  Thanks All