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• how can i stop ffmpeg when no new frame come to /dev/video0

  17 mai 2022, par itirou tarou

  I am now modifying stream from camera with our program(programA) and output as .ts files like below.

  


  camera => programA => /dev/video0 => ffmpeg => .ts files

  


  When camera stopped, programA stop automatically and no new frame arrive to /dev/video0.
I want ffmpeg stop automatically in such situation.
What ffmpeg option should I use ?
Currently I'm using option below, but ffmpeg doesn't stop.

  


  ffmpeg -f video4linux2 -i /dev/video0 -vsync vfr -f hls -c:v h264_nvenc out.m3u8


  


  Edited :
  
I tried to invalidate /dev/video0 but it failed like below.

  


  # modprobe -r v4l2loopback
modprobe: FATAL: Module v4l2loopback is in use.


  


  After I stopped programA and ffmpeg, the command success.
  
ProgramA is kicked by systemd service and restart automatically when it stopped.
  
ffmpeg is kicked by programB, but programB doesn't control programA.
  
But it sounds like good idea to inform B so B can kill ffmpeg.
  
I'll try that way. Thank you.

  


• Why do I get a black box when I tile pictures with -filter_complex tile=2x1 in FFmpeg ?

  19 juin 2016, par Mateusz Piotrowski

  As I was trying to write a script (which attempts to join two pictures eventually) using FFmpeg I came across a very weird behaviour.

  I’ve found a command in an accepted answer for the very same problem I had (How to join two image into one by ffmpeg ?) :

  ffmpeg -i a.jpg -i b.jpg -filter_complex scale=120:-1,tile=2x1 output.jpg

  • Input : a.jpg, b.jpg

    

  • Output : output.jpg

    

  What happened to the B cat ? Why is it missing from the output image ? I couldn’t find any information why tile=2x1 behaves like this.

• FFmpeg : How to convert vertical/horizontal video (any size) with black sides, to 1080x1350 vertical video with blurred background sides/bottom-top

  12 octobre 2023, par devweb

  i've been trying to make a ffmpeg 'filter_complex' code to make what i need but i can't, i've used some codes here on stack but non works for what i need, each is like for a different size/dimension.
I'm trying to make videos like Instagram posts (tallest allowed) : 1080 x 1350

  


  Bassically, horizontal videos with blurred sides or bottom-top.

  


  Any help will be awesome, thanks !

  


  This is the principal which i tried

  


  Something like this :

  


  Example 1
Example 2

  


  Here some codes i tried to worked with and changing stuff :
filter_complex='[0:v]scale=1080*2:1350*2,boxblur=luma_radius=min(h\\,w)/20:luma_power=1:chroma_radius=min(cw\\,ch)/20:chroma_power=1[bg];[0:v]scale=-1:1080[ov];[bg][ov]overlay=(W-w)/2:(H-h)/2,crop=w=1080:h=1350'

  


  filter_complex='[0:v]scale=ih*5/4:-1,crop=h=iw*4/5,gblur=sigma=20[blurred];[blurred][0:v]overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2'

  


  filter_complex='[0:v]scale=1080:1350,setsar=1,gblur=sigma=20[blurred];[blurred][0:v]overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2'