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• fallback input when blackscreen ffmpeg

  23 novembre 2022, par renadr

  I would like to have a "fallback" video when using the ffmpeg command. The goal is that I broadcast a video and once this one displays an almost black screen, there should be a switch to the fallback, and re-switch when the black screen is over. I know that we can detect the "blackframe" but I'm lost then.. If anyone have an idea ?

  


  I'm at this point for the moment (I'm using streamlink for getting the input) :

  


  streamlink <> best -O | ffmpeg -re -i pipe:0 -c:v libx264 -vf "blackframe=amount=40:thresh=5" -c:a aac -strict -2 -f flv <> | grep blackframe


  


  thank you

  


• 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