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• Speed of moving text drawtext filter - FFMPEG

  8 mai 2016, par BOB

  I’m using this command to move text from one place to another using ffmpeg

  ffmpeg -i VideoInput.mp4 \
  
         -vf "drawtext=enable='between(t,12,14)':fontfile=myfont.otf:text='Test test': \
  
             x='x1+(x2-x1)*(t-t1)/(t2-t1)':y='y1+(y2-y1)*(t-t1)/(t2-t1)':fontsize=65" \
  
         -acodec copy outputVideo.mp4

  Now I need to control the speed of moving the text. I want to speed it up.
  How do I control the speed ?

  Any suggestions ?

  Thank you

• How to increase image export/extract speed when using ffmpeg ?

  7 février 2020, par Los Pollos Hermanos

  I’m extracting all frames from mp4 video (video fps : 25) with fps -r 25 param, using ffmpeg.

  Here is command that I used : ffmpeg -i input.mp4 -r 25 frame_%%02d.bmp. It works.

  In start of extracting proccess ffmpeg have speed=~4x and after 200-300 frame speed slow down to ~0.3x. But CPU using is only 3% max, memory also ok. Output Metadata :

      Encoder         : Lavf58.12.100
  
      Stream #0:0(und): Video: bmp, bgr24, 1920x1080, q=2-31, 200 kb/s, 25 fps, 25
  
   tbn, 25 tbc (default)

  Question : How can extract faster ?

  I’ve tried with this parameters, but speed not changed :

  • -threads 4 threads count has changed but speed not,
  • -preset with veryfast and ultrafast also nothing.

• How to use -vf format="gray" in ffmpeg python

  22 août 2022, par user19551045

  I am trying to use the -vf format="gray" in ffmpeg-python and I can't seem to get the syntax right. From what I have seen, ffmpeg-python has a set of filter_name options you can use, and then there is also the option to use .filter_() to just put in the ffmpeg commands directly in.

  


  I have tried using both and seem to get the same error, where ffmpeg-python wants me to declare a filter_name and from what I am seeing in the documentation, format=gray doesn't fall under any of the filter_name options.

  


  If I take this approach, it works :

  


  (
        ffmpeg.input(img_seq_template, framerate=framerate, **input_options)
        .filter("format", "gray")
        .output(filename=output_path, **output_options)
        .run(overwrite_output=True)
   )


  


  However, I want to also use a dictionary in the filter(), which then requires me to put in a filter_name. The goal would be to have something like below working :

  


  filter_options = {'format' : 'gray'}

(
        ffmpeg.input(img_seq_template, framerate=framerate, **input_options)
        .filter(filter_name = "some_filter_name", **filter_options)
        .output(filename=output_path, **output_options)
        .run(overwrite_output=True)
    )


  


  Any ideas on what I could put into the filter_name to get this running would be amazing ! All suggestions welcome, thanks so much !