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• ffmpeg concat creates video with frame timings off by 0.1-0.2 seconds [closed]

  17 octobre 2023, par brain-geek

  I am trying to create some variable frame rate video for test data, however frame timings of the result are consistently off. I tried both ffmpeg 4 and ffmpeg 6, but having same results. I am using example from the website as a reference.

  


  Here is the script to generate video :

  


  rm -f framelist.txt output.mp4

convert -size 640x480 -gravity center -background black -fill purple label:0-2 -units PixelsPerInch -density 254 0-2.png
echo "file '0-2.png'" >> framelist.txt
echo "duration 2" >> framelist.txt
convert -size 640x480 -gravity center -background black -fill purple label:2-2.5 -units PixelsPerInch -density 254 2-2.5.png
echo "file '2-2.5.png'" >> framelist.txt
echo "duration 0.5" >> framelist.txt
convert -size 640x480 -gravity center -background black -fill purple label:2.5-3 -units PixelsPerInch -density 254 2.5-3.png
echo "file '2.5-3.png'" >> framelist.txt
echo "duration 0.5" >> framelist.txt
convert -size 640x480 -gravity center -background black -fill purple label:3-3.25 -units PixelsPerInch -density 254 3-3.25.png
echo "file '3-3.25.png'" >> framelist.txt
echo "duration 0.25" >> framelist.txt
convert -size 640x480 -gravity center -background black -fill purple label:3.25-3.5 -units PixelsPerInch -density 254 3.25-3.5.png
echo "file '3.25-3.5.png'" >> framelist.txt
echo "duration 0.25" >> framelist.txt
convert -size 640x480 -gravity center -background black -fill purple label:3.5-3.75 -units PixelsPerInch -density 254 3.5-3.75.png
echo "file '3.5-3.75.png'" >> framelist.txt
echo "duration 0.25" >> framelist.txt
convert -size 640x480 -gravity center -background black -fill purple label:3.75-4 -units PixelsPerInch -density 254 3.75-4.png
echo "file '3.75-4.png'" >> framelist.txt
echo "duration 0.25" >> framelist.txt
convert -size 640x480 -gravity center -background black -fill purple label:4-10 -units PixelsPerInch -density 254 4-10.png
echo "file '4-10.png'" >> framelist.txt
echo "duration 6" >> framelist.txt
convert -size 640x480 -gravity center -background black -fill purple label:10-20 -units PixelsPerInch -density 254 10-20.png
echo "file '10-20.png'" >> framelist.txt
echo "duration 10" >> framelist.txt
echo "file '10-20.png'" >> framelist.txt

ffmpeg -f concat -i framelist.txt -vsync vfr -pix_fmt yuv420p output.mp4


  


  When after that I do ffprobe, I get not expected frame timings :

  


  $ ffprobe -v error -select_streams v:0 -show_frames output.mp4|grep pts_time
pts_time=0.000000
pts_time=2.000000
pts_time=2.520000
pts_time=3.000000
pts_time=3.240000
pts_time=3.520000
pts_time=3.760000
pts_time=4.000000
pts_time=10.000000
pts_time=20.000000


  


  First and second are correct - 0 and 2, however third should be 2.5 instead of 2.52 . Third is once more correct as 3.0, but fourth should be 3.25, not 3.24 . Last 3 are correct as well (4, 10, 20).

  


  What could be the problem, and how do I get the correct frame timings here ?

  


• ffmpeg add overlay image to command with already drawtext

  29 octobre 2020, par fedep11

  I have two ffmpeg commands I would like to add an overlay image to both :

  


  ffmpeg -i "video.mp4" -filter_complex "drawtext=textfile=sub.txt:fontfile=SourceSansPro-Bold.ttf:fontcolor=white:fontsize=100: box=1: boxcolor=black@0.5: boxborderw=5: x=200:y=h-th-200:enable='between(t,1,9)',fade=t=in:start_time=1:d=1:alpha=1,fade=t=out:start_time=8:d=1:alpha=1[fg];[0][fg]overlay=format=auto,format=yuv420p" -an -vcodec libx264 -r 25 -crf 17 -aspect 16/9 out.mp4

ffmpeg -i "video.mp4" -filter_complex "color=black@0:100x100,format=yuva444p[c]; [c][0]scale2ref[ct][mv0];[ct]setsar=1,split=4[t1][t2][t3][t4];[t1]drawtext=textfile=1.txt:fontfile=SourceSansPro-Bold.ttf:fontsize=100:fontcolor=white: box=1: boxcolor=black@0.5: boxborderw=5: x=200:y=h-th-200,fade=t=in:st=1:d=1:alpha=1,fade=t=out:st=7:d=1:alpha=1[txta1];[t2]drawtext=textfile=2.txt:fontfile=SourceSansPro-Bold.ttf:fontsize=100:fontcolor=white: box=1: boxcolor=black@0.5: boxborderw=5: x=200:y=h-th-200,fade=t=in:st=9:d=1:alpha=1,fade=t=out:st=15:d=1:alpha=1[txta2];[t3]drawtext=textfile=3.txt:fontfile=SourceSansPro-Bold.ttf:fontsize=100:fontcolor=white: box=1: boxcolor=black@0.5: boxborderw=5: x=200:y=h-th-200,fade=t=in:st=17:d=1:alpha=1,fade=t=out:st=24:d=1:alpha=1[txta3];[t4]drawtext=textfile=4.txt:fontfile=SourceSansPro-Bold.ttf:fontsize=100:fontcolor=white: box=1: boxcolor=black@0.5: boxborderw=5: x=200:y=h-th-200,fade=t=in:st=26:d=1:alpha=1,fade=t=out:st=28:d=1:alpha=1[txta4];[mv0][txta1]overlay=x='0':y='0':shortest=1[mv1];[mv1][txta2]overlay=x='0':y='0':shortest=1[mv2];[mv2][txta3]overlay=x='0':y='0':shortest=1[mv3];[mv3][txta4]overlay=x='0':y='0':shortest=1" -an -vcodec libx264 -r 25 -crf 17 -aspect 16/9 out.mp4


  


• ffmpeg - Understand images to video output, players show different images and lengths

  8 juillet 2023, par Matt C

  I'm using multiple images to create a video with each image on a 1-second long frame. This is the command I'm using :

  


   ffmpeg -framerate 1 -i 'image%d.jpg' -c:v libx264 -r 1 -pix_fmt yuv420p out.mp4


  


  This seems straightforward and exactly what many others have done with success. However, the output I get is an mp4 which windows file explorer says is 4 seconds long, and is different in VLC and Windows media player and neither is the desired output.

  


  In Windows : the video plays for 4 seconds with a black screen and at this point the time line at the bottom is filled up at 4 seconds, indicating the video is over. But it keeps playing, for another 4 seconds. And the last 4 seconds (from 0:04 to 0:07) is actually the desired output.

  


  





  


  


  


  


  



  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  Frame	Image
  1	black screen
  2	black screen
  3	black screen
  4	black screen
  5	image1.jpg
  6	image2.jpg
  7	image3.jpg
  8	image4.jpg

  


  


  In VLC : the video shows last image supplied as input for 3 seconds, followed by the second to last image for 1 second.

  


  





  


  


  


  


  



  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  Frame	Image
  1	image4.jpg
  2	image4.jpg
  3	image4.jpg
  4	image3.jpg

  


  


  Questions :

  


  

  1. How/Why are these different in different players ?

  


  2. Why, in VLC, are only two images showing up, and why would one of them last for 3 seconds ?

  


  3. In Windows, why/how is the video 8 seconds long but shows up as 4 seconds both in the file explorer and in the actual media player ?

  


  4. How do I get the desired output, and what caused my case to not work as it did for seemingly most others ?