4

I'm encoding a video with a transparent PNG using ffmpeg. I noticed there's a slight black outline surrounding the image. Is there any way to remove it?

Output image: image

Transparent PNG sample: image

My ffmpeg command

ffmpeg -hide_banner -y -ss 0.0 -t 8.5 -i C:\Users\Admin\Desktop\test_movies\6.mp4 -i C:\Users\Admin\Desktop\test_movies\text_and_emoji.png -filter_complex [0:v]setpts=PTS-STARTPTS,scale=640:640:force_original_aspect_ratio=decrease,pad=640:640:(ow-iw)/2:(oh-ih)/2:color=#18ffff[0v];[1:v]scale=556.24744:141.41884[1v];[0v][1v]overlay=(W-w)/2-(W/2-325.33328):(H-h)/2-(H/2-567.7075):enable='between(t,0.0,8.5)' -ac 2 -ar 44100 -vcodec libx264 -g 75 -r 20 -preset ultrafast -strict experimental C:\Users\Admin\Desktop\test_movies\test.mp4

Last edit 1:

I tried using without [1:v]scale=556.24744:141.41884[1v], the output still have the slight outline

Sample output: image

Sample code:

ffmpeg -hide_banner -y -ss 0.0 -t 8.5 -i C:\Users\Admin\Desktop\test_movies\white.mp4 -i C:\Users\Admin\Desktop\test_movies\text_and_emoji.png -filter_complex [0:v]scale=640:640:force_original_aspect_ratio=decrease,pad=640:640:(ow-iw)/2:(oh-ih)/2:color=#18ffff[0v];[0v][1:v]overlay=(W-w)/2-(W/2-325.33328):(H-h)/2-(H/2-567.7075):enable='between(t,0.0,8.5)' -ac 2 -ar 44100 -vcodec libx264 -preset ultrafast -strict experimental C:\Users\Admin\Desktop\test_movies\test.mp4

Last edit 2:

I tried another one with added alpha=premultiplied with latest ffmpeg version. It somehow removed the outline, but the quality of the picture reduced alot till it seems like it's pixelated. Plus. there's another unknown white layer at the back of the image.

Output video output video

Sample code:

C:\Users\Admin\Downloads\ffmpeg-20180102-57d0c24-win64-static\bin\ffmpeg -y -ss 0.0 -t 8.5 -i C:\Users\Admin\Desktop\test_movies\white.mp4 -i C:\Users\Admin\Desktop\test_movies\text_and_emoji.png -filter_complex [0:v]scale=640:640:force_original_aspect_ratio=decrease,pad=640:640:(ow-iw)/2:(oh-ih)/2:color=#00ffff[0v];[1:v]scale=480:120[1v];[0v][1v]overlay=(W-w)/2-(W/2-325.33328):(H-h)/2-(H/2-567.7075):alpha=premultiplied:enable='between(t,0.0,8.5)' -ac 2 -ar 44100 -vcodec libx264 C:\Users\Admin\Desktop\test_movies\test.mp4

Latest edit 3:

As suggested by @Mulvya, I combined his code with alpha=premultiplied and it seems alot better now, with very slight black outline (almost not visible)

Output video: Output video

Sample code:

C:\Users\Admin\Downloads\ffmpeg-20180102-57d0c24-win64-static\bin\ffmpeg -y -ss 0.0 -t 8.5 -i C:\Users\Admin\Desktop\test_movies\white.mp4 -i C:\Users\Admin\Desktop\test_movies\text_and_emoji.png -filter_complex [0:v]setpts=PTS-STARTPTS,scale=640:640:force_original_aspect_ratio=decrease,pad=640:640:(ow-iw)/2:(oh-ih)/2:color=#18ffff[0v];[1:v]premultiply=inplace=1,scale=480:120[1v];[0v][1v]overlay=(W-w)/2-(W/2-325.33328):(H-h)/2-(H/2-567.7075):alpha=premultiplied:enable='between(t,0.0,8.5)':format=rgb,format=yuv420p -ac 2 -ar 44100 -vcodec libx264 C:\Users\Admin\Desktop\test_movies\test.mp4
kklmarvelmedia
  • 61
  • 1
  • 6

1 Answers1

1

This is due to a bug in the overlay filter, since fixed. Alter your filtergraph to to this,

"[0:v]setpts=PTS-STARTPTS,scale=640:640:force_original_aspect_ratio=decrease,pad=640:640:(ow-iw)/2:(oh-ih)/2:color=#18ffff[0v];[1:v]premultiply=inplace=1,scale=556.24744:141.41884[1v];[0v][1v]overlay=(W-w)/2-(W/2-325.33328):(H-h)/2-(H/2-567.7075):enable='between(t,0.0,8.5)':format=rgb,format=yuv420p"

You'll need a FFmpeg version from after Dec 16 2017 for this.

Gyan
  • 85,394
  • 9
  • 169
  • 201
  • thanks for the solution. It somehow removes the outline, but the quality of the image reduced alot till it seems like it's pixelated. Plus. there's another unknown white layer at the back of the image. I attached a screenshot in my main thread question. – kklmarvelmedia Jan 08 '18 at 11:13
  • I added with `alpha=premultiplied` and it seems alot better now, with very slight black outline (almost not visible). I attached another screenshot there. However, if i dun add `alpha=premultiplied`, it will show the black outline. – kklmarvelmedia Jan 09 '18 at 02:07
  • though an old answer, I am using this solution but, as a result, the overlay output is brighter than the input background, even if the overlayed image is completely 100% transparent. Do you know why or how to avoid it? – Sagi Mann Jun 30 '20 at 10:34