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• ffmpeg - adding white background to complex png command

  5 août 2022, par Uriel Romano

  I have a complex concatenation of commands working perfectly :

  


  ffmpeg -r 24 -i "D:\batches\S3025C-SV_"%%03d.png -vf "scale=out_color_matrix=bt709,eq=gamma=1:saturation=1,fps=25, crop=trunc(iw/2)*2:trunc(ih/2)*2" -color_primaries bt709 -color_trc bt709 -colorspace bt709 "D:\batches\S3025C-SV.mp4"

  


  Now I need to add a white background to this mp4 render, as ffmpeg is using a black one by default. I've found the following command here :

  


  -filter_complex "[0:v] setpts=PTS-STARTPTS [graphs]; [1:v][graphs] overlay=shortest=1 [out]" -map "[out]"

  


  How could I combine this operation into the first one ? I've tried a couple of different syntaxes but couldn't get it to work.

  


  Thanks for your help !

  


• Is ffmpeg's chromakey filter broken when matching black/white ?

  7 janvier 2023, par Taylor Brown

  I have a file, colors.png. It looks like this :

  



  Let's say I want to make the red square transparent. When I run ffmpeg -i colors.png -filter_complex "[0]chromakey=0xff0000:similarity=0.1:blend=0.0[out]" -map "[out]" colors-rm-red.png (notice I use similarity=0.1 to make this work), I get exactly that :

  



  How about making the blue square transparent ? ffmpeg -i colors.png -filter_complex "[0]chromakey=0x0000ff:similarity=0.1:blend=0.0[out]" -map "[out]" colors-rm-blue.png works too !

  



  But what about replacing black ? ffmpeg -i colors.png -filter_complex "[0]chromakey=0x000000:similarity=0.1:blend=0.0[out]" -map "[out]" colors-rm-black.png gives me this :

  



  And likewise, replacing white with ffmpeg -i colors.png -filter_complex "[0]chromakey=0xffffff:similarity=0.1:blend=0.0[out]" -map "[out]" colors-rm-white.png gives me the same result :

  



  Why is this ? Even if I use similarity=0.01, which according to the docs "matches only the exact key color", this still doesn't work when I'm trying to make black/white transparent. Is ffmpeg broken, or am I misunderstanding the chromakey filter ?

  


• FPV-Camera Input in Black and White / losses Color on conversion with FFMPEG [closed]

  22 décembre 2023, par LyffLyff

  so we're working on our end-of-school project and it's an FPV-Drone with an Analogue Camera on it. Plan is to send the video feed to a Raspberry Pi running an RTMP-Server from where a Phone-Application can view the live Video of the camera.

  


  To convert this analogue Data from the camera we use a USB2.0 Grabber (this one).

  


  To create the RTMP Stream from the converted USB-Input we use FFMPEG with the following command :

  


  


  fmpeg -f v4l2 -input_format yuyv422 -i /dev/video0 -c:v libx264 -crf 20 -preset ultrafast -b:v 2000k -fflags nobuffer -rtmp_live live -f flv rtmp ://192.168.8.107:554/live/stream

  


  


  It works fine, but the main problems at the moment are :

  


  

  • the video is in Black and White
B&W Image Stream

  


  • the stream has a delay of 10-20s depending on the network

  


  


  When I'm using the official Software provided by the Reseller I had the same problem, but as soon as it set PAL/BDGHI in the Settings the colour was shown correctly :

  


  Settings and Color Image in official software

  


  the video is in Black and White

  


  Does anyone know what settings there are to correctly decode the feed from the Camera and send the video with the colour over RTMP ? I don't know if this is the right place to ask this question, but I'm running out of ideas and every single decoder I have tried apart from the ones I'm currently using does not work.

  


  Any help is greatly appreciated :)