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• How to concat multiple explicit image paths to video with ffmpeg

  22 juillet 2019, par jimboslice

  I am trying to figure out how to create a video from explicit paths to an image sequence.
  I am writing these images from Houdini.

  Instead of doing some kind of regex matching to replace $F3 with %03d I am trying to figure out how to concat the image paths into a video.

  I’m trying to do something like this :

  ffmpeg -y -framerate 12 -i -start_number 1 -i test_00001.jpg -start_number 2 -i test_00002.jpg -start_number 3 -i test_00003.jpg -start_number 4 -i test_00004.jpg -start_number 5 -i test_00005.jpg -start_number 6 -i test_00006.jpg -start_number 7 -i test_00007.jpg -start_number 8 -i test_00008.jpg -start_number 9 -i test_00009.jpg -filter_complex "concat=n=3" -c:v libx264 -profile:v high -crf 20 -pix_fmt yuv420p $HOME/Desktop/test.mp4

  This result only plays a couple of frames in the result video

  If I write the images to a text file with the following format

  file '/Volumes/hqueue/projects/Fire/render/test_1.jpg'
file '/Volumes/hqueue/projects/Fire/render/test_2.jpg'
file '/Volumes/hqueue/projects/Fire/render/test_3.jpg'
file '/Volumes/hqueue/projects/Fire/render/test_4.jpg'
file '/Volumes/hqueue/projects/Fire/render/test_5.jpg'
file '/Volumes/hqueue/projects/Fire/render/test_6.jpg'
file '/Volumes/hqueue/projects/Fire/render/test_7.jpg

  and then run a command like the following
  ffmpeg -y -framerate 12 -f concat -i /var/folders/fy/8zlxyq497kz0nzgb1nqc9xf59rwbjm/T/image_list.txt -c:v libx264 -profile:v high -c copy -crf 20 -pix_fmt yuv420p $HOME/Desktop/test.mp4

  I get the following output

  [concat @ 0x7f870e809c00] Unsafe file name '/Volumes/hqueue/projects/Fire/render/test_1.jpg'
/var/folders/fy/8zlxyq497kz0nzgb1nqc9xf59rwbjm/T/image_list.txt: Operation not permitted

  Right now it’s producing a video, but only with a couple of the input frames.

• ffmpeg set start to the 1st keyframe

  6 janvier 2018, par Zoltan Hernyak

  I have several videos which start not at keyframe - so the first couple of seconds is a frozen picture. With ffprobe I can see where is the 1st keyframe, where the video really starts. I wonder if there is a way to set the .mkv libx264 encoded video to start at this point, not at 0.00 ? May it easier as reencoding all videos - ffprobing one-by-one and seeking through the 1st couples of seconds.

  If it is not possible, please, show me a way to tell ffprobe list not all keyframes but the 1st only. It takes too long to list all the keyframes for a script - when I need only the 1st keyframe information.

• Try to execute ffmpeg in python - subtitles error

  3 septembre 2022, par user103162

  I try to exectute :
./ffmpeg.exe -i "video.mkv" -vf subtitles="video.mkv" "video.mp4"
This command works fine

  


  But not in my python code

  


  
from pathlib import Path
import subprocess
import os


ffmpeg = r"D:\Archives\ffmpeg.exe"
os.chdir(r"D:\temp\video")
videos = Path(".")

for file_mkv in videos.glob("*.mkv"):
    file_mp4 = file_mkv.with_suffix(".mp4")
    subprocess.run([ffmpeg, "-i", file_mkv, "-vf", f'subtitles="{file_mkv}"', file_mp4])



  


  Error :
[Parsed_subtitles_0 @ 0000020cb26222c0] Unable to open "video.mkv"
[AVFilterGraph @ 0000020cb715a380] Error initializing filter 'subtitles' with args '"video.mkv"'
Error reinitializing filters !
Failed to inject frame into filter network : Invalid argument
Error while processing the decoded data for stream #0:0
Conversion failed !