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• FFMPEG overlay video with black background over an image not working without any errors

  19 juin 2018, par bil80

  I have a snow effect video with black background snow.mp4, and i want to overlay it over a fixed jpeg image.jpg
  The generated output video result was only with the image without the snow effect, my ffmpeg version is : 3.2.10, i don’t understand why it is not working with me, have you an idea ?

  This is my command line :

  ffmpeg -i image.jpg -i snow.mp4 -filter_complex '[1:v]scale=1280x768,setdar=16:9,colorkey=0x000000:0.3:0.2[ckout];[0:v]scale=1280x768,setdar=16:9,[ckout]overlay[out]' -map '[out]' output.mp4

  I tried also with the chromakey instead of colorkey, without success :/

  This is the result video that i got :
  output.mp4

  What i want is this result with snow effect : output_with_snow_effect.mp4

• getting black screen while trying to record dockerized lxde using ffmpeg

  16 mars 2023, par Itzik.B

  I have created a docker image that has LXDE and TightVNCServer.

  


  # Pull base image.
FROM ubuntu

# Install LXDE and VNC server.
RUN apt-get update
RUN apt-get install -y xvfb
RUN DEBIAN_FRONTEND=noninteractive apt-get install -y lxde-core lxterminal tightvncserver
RUN rm -rf /var/lib/apt/lists/*
RUN touch /root/.Xresources
RUN touch /root/.Xauthority
COPY xstartup /root/.vnc/xstartup
RUN chmod +x /root/.vnc/xstartup
#Install Node.js & npm

# Define working directory.
WORKDIR /data

COPY * /data

RUN apt-get install -y ffmpeg


  


  I am running this container using this command :

  


  docker run -it --rm -v /data:/data -p 5901:5901 -e USER=root ubuntudsktp  bash -c "vncserver :1 -geometry 1280x800 -depth 24 && tail -F /root/.vnc/*.log"

  


  I am logging into this container using VNC and running this command to record the whole screen :

  


  ffmpeg -f x11grab -i :1.0 output.webm

  


  After the recording was over, I opened the video and I could see that the video is completely blank(black screen).

  


  I know there is a "screen" that I need to tell ffmpeg to record but its works only on -i :1.0.

  


  I have also tried to run it using :

  


  DISPLAY=:1 ffmpeg -f x11grab -i :1.0 output.webm
And the results are the same.

  


  What I am missing here ?

  


• How to concat videos from a file list while adding black fade transitions in ffmpeg

  6 avril 2022, par connor449

  I have a piece of code that concats videos from a file list. It works perfectly.

  


  ffmpeg -f concat -safe 0 -i file_list.txt -c copy mergedVideo.avi


  


  However, I want to add a black fade transition between each video. I found this code snippet that apparently does this, but it requires you to input each file by hand.

  


  ffmpeg -i in.mp4 -i main.mp4 -i out.mp4 -filter_complex \
  "[0:v]fade=type=out:duration=2:start_time=28,setpts=PTS-STARTPTS[v0]; \
   [1:v]fade=type=in:duration=2,fade=type=out:duration=2:start_time=28,setpts=PTS-STARTPTS[v1]; \
   [2:v]fade=type=in:duration=2,setpts=PTS-STARTPTS[v2]; \
   [v0][0:a][v1][1:a][v2][2:a]concat=n=3:v=1:a=1[v][a]" \
  -map "[v]" -map "[a]" output.mp4


  


  I want to be able to read all the video files from a txt file as I have hundreds of videos. How do I combine these two snippets, or is there a better way to accomplish the concat with fade transitions ?