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• How to put a png onto an mp4/gif using imagemagick ?

  24 juillet 2022, par Harrison

  TLDR : How do I convert an MP4 to GIF without sacrificing quality ? How can I lay a PNG on a GIF without sacrificing quality ? And how to get rid of the flicker from combining them ?

  


  So I have an MP4 that is 3000x3000 and a PNG that is 1000x1000.

  


  The end result that I want is a GIF that is 1000x1000 where the PNG is layered on top of the MP4 as a background.

  


  These are the step I tried and the issues I am running into. Mainly the issues I am running into are a loss in quality.

  


  MP4 to GIF :

  


  


  1. I have converted the MP4 to a gif with ffmpeg -i background.mp4 background.gif. Result : A major loss of quality in the gif.

     


  


  2. Instead of that - I tried an online converter. Works better but would like to do it on my own. But I will use this GIF from the online converter in the next examples. Still a slight loss of quality but not near as bad.

     


  


  3. I have sized down my gif using convert temporary.gif -coalesce -resize 1000x1000 smaller.gif. (Have also tried with specifying the -size 3000x3000 but no difference really.) Another minor loss of quality there.

     


  


  


  PNG ontop of GIF - Trial 1

  


  

  1. I have converted my PNG to a single page GIF with convert front.png front.gif (Along with some other options). Loses quality, anything that fades or is semi see through gets turned into a solid pixel.

  


  2. Duplicated this page a bunch of times to match number of pages in my background gif using convert front.gif front.gif front.gif multiple times.

  


  3. Merged background and front together with convert background.gif -coalesce null: front.gif -layers composite both.gif. Little more lose of quality and some flickering on the foreground..? Tried some other variations but thats the best I got.

  


  


  PNG on GIF - Trial 2

  


  

  1. Instead of making a GIF of the PNG, I am just using the original PNG with the background.gif like this convert smaller.gif -coalesce null: front.png -layers composite -layers optimize both.gif. This one comes out weird. The from image is very different looking in color and flickery. Not gonna work.

  


  2. Tried without optimization. convert smaller.gif -coalesce null: front.png -layers composite test.gif. This on is closer. The foreground looks great, but is just flickery still ! Again the background is not great but it doesn't seem to have much more impact from after the original mp4 conversion. Did this without -coalesce and still get the same output.

  


  


  The best I can get is a decent front image with details preserved - but flickery. On top of a lossy background.

  


  How can I go about doing this with imagemagick or some other library ?

  


• Vinyl record animation with ffmpeg

  14 avril 2023, par pabsdenn

  Is it possible to archive this with ffmpeg ?

  


  Basically I want to have a black or vinyl background, one circle for the cover and one circle for the hole. I then need to replace the cover with an image of 500x500px and let it rotate as loop with a certain speed.

  


  Or is it better to automate it with e.g. After Effects ?

  


• Convertion of mp3 file with ffmpeg results in a file with wrong length [duplicate]

  16 avril 2018, par Arthur Efixty

  This question already has an answer here :

  • ffmpeg : add subtitles to mp4 with out creating a new file
    
    1 answer
    

  I wrote a simple script for Linux where I loop through the folder (containing only .mp3 files) and add an album art to every item.

  Here is my code :

  for file in ~/Desktop/Rise\ Against/*
  
      do
  
          ffmpeg -i "${file}" -i ~/Desktop/appeal\ to\ reason.jpeg -map 0:0 -map 1:0 -codec copy -id3v2_version 3 \-metadata:s:v title="Album cover" -metadata:s:v comment="Cover (front)" "${file%}";
  
      done

  If I set the output filename to hardcoded value like out.mp3 then it works fine. But I need these files to have the same name as existing and overwrite them.

  Running this script results in having all files edited as expected (the album art changed) but they all have a length of 3 seconds. In terminal I get this [mp3 @ 0xc695e0] Audio packet of size 378219 (starting with 6B0855F2...) is invalid, writing it anyway.

  Thanks in advance !