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• German umlauts in ffmpeg drawtext filter

  15 août 2020, par Gert Gottschalk

  I need help getting german umlauts 'äüö' displayed properly/(at all) in ffmpeg drawtext filter. I can't say at this time if my inability comes from lack of ffmpeg know-how or machine configuration or both. Your input is much appreciated.

  



  In ffmpeg cmd line I have :

  



  /home/tools/bin/ffmpeg -loop 1 -i RAW2TIF_01_png_1080/IMG_1119.png -c:v libx264 -vf drawtext="fontsize=60:fontcolor=yellow:fontfile=/usr/share/fonts/truetype/freefont/FreeSans.ttf:textfile=./Scripts/header_text.txt:x=(w-text_w)/2:y=(h-text_h-line_h)/2" -t 10 -pix_fmt yuv420p  -crf 16 -r 24 -y ./Video/header_txt.mp4


  



  Note the 'drawtext' call.

  



  My linux machine where I run ffmpeg is setup for US keyboard and characters. So my first roadblock is to get the umlauts into the text in some editor. I tried typing 'alt-numerical' sequences, but the special characters will not show in vi, vim, emacs.

  



  If I were to have the special characters in a textfile I would not know if/how ffmpeg is able to handle them.

  



  A search on popular engine for 'ffmpeg drawtext umlaut' does not return any (for me) meaningful returns.

  



  Thanks,
Gert

  


• FFMPEG Encoding to prores 4444 with alpha doesn't retain original alpha [closed]

  19 mai 2023, par Nick Weeden

  I'm trying to convert an rgba png to prores 4444 with an alpha. When I run the following command it will create prores file with an alpha. But, the alpha is full white, it doesn't retain the values I put in.

  


  ffmpeg -start_number 1001 -r 24.000 - "pngWithAlpha_%06d.png" -c:v prores_ks -profile:v 4 -alpha_bits 16 -y "proresWithAlpha.mov"


  


  I've tried this with both FFMPEG 4.2.2 and 6.0.0 on a linux system, I'm not sure if I'm doing it wrong or if it is a bug.

  


  Looking at this post it seems it should be possible (they're complaining about quality not a fully missing transfer of the alpha).

  


  I would expect it to pass the alpha straight through but it doesn't. I used alpha_extract to copy the alpha in to the rgb to confirm I'm able to read the alpha from the png, which worked. But the alpha was still full white.

  


• colors messed up (distorted) when making a gif from png files using ffmpeg

  13 novembre 2019, par wxyz

  I have a sequence of png images : image_00.png, image_01.png, image_02.png, etc. I want to convert them to a gif, so I tried the command

  ffmpeg -i image_%02d.png video.gif

  Unfortunately, the resulting gif has distorted colors. More specifically, it added a weird sort of yellow haze around some objects in the video.

  I also tried using the command above with all possible pixel format options (which I determined using the command ffmpeg -h encoder=gif) : rgb8, bgr8, rgb4_byte, bgr4_byte, gray, pal8. For example ffmpeg -i image_%02d.png -pix_fmt rgb8 video.gif. Unfortunately, all of the resulting gifs had some sort of color distortion.

  I also observed that this distortion does not occur if I convert the images to mp4 instead of gif. However, if I try converting that mp4 to a gif, I end up with the distortion again.

  How can I produce this gif without color distortion ?