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• ffmpeg image watermark on video first half of video on Bottom left and next half of video on Top Right

  23 novembre 2020, par qedsl

  I was playing with this for several hours, I couldn't make so thought of reaching for help, Can you please help me in framing the ffmpeg command to display the watermark Image on the video, For the Initial half video the watermark should be on the bottom left and for the rest half video the watermark shop be on the right top.

  


  Bottom left : ffmpeg -i input.mp4 -i logo.png -filter_complex "overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2" -codec:a copy output.mp4

  


  Top right :
ffmpeg -i input.mp4 -i logo.png -filter_complex "overlay=main_w-overlay_w-5:5" -codec:a copy output.mp4

  


  Also, I had a look on this for Timeoverlay ffmpeg watermark first 30 second.

  


  How to merge all these and satisfy my requirements as mentioned above ?

  


• Trying to capture display output for real-time analysis with OpenCV ; I need help with interfacing with the OS for input

  26 juillet 2024, par mirari

  I want to apply operations from the OpenCV computer vision library, in real time, to video captured from my computer display.
The idea in this particular case is to detect interesting features during gameplay in a popular game and provide the user with an enhanced experience ; but I could think of several other scenarios where one would want to have live access to this data as well. 
At any rate, for the development phase it might be acceptable using canned video, but for the final application performance and responsiveness are obviously critical.

  



  I am trying to do this on Ubuntu 10.10 as of now, and would prefer to use a UNIX-like system, but any options are of interest.
My C skills are very limited, so whenever talking to OpenCV through Python is possible, I try to use that instead.
Please note that I am trying to capture NOT from a camera device, but from a live stream of display output ; and I'm at a loss as to how to take the input. As far as I can tell, CaptureFromCAM works only for camera devices, and it seems to me that the requirement for real-time performance in the end result makes storage in file and reading back through CaptureFromFile a bad option.

  



  The most promising route I have found so far seems to be using ffmpeg with the x11grab option to capture from an X11 display ;
(e.g. the command
ffmpeg -f x11grab -sameq -r 25 -s wxga -i :0.0 out.mpg
captures 1366x768 of display 0 to 'out.mpg').
I imagine it should be possible to treat the output stream from ffmpeg as a file to be read by OpenCV (presumably by using the CaptureFromFile function) maybe by using pipes ; but this is all on a much higher level than I have ever dealt with before and I could really use some directions. 
Do you think this approach is feasible ? And more importantly can you think of a better one ? How would you do it ?

  


• Stack two video side and side but play one after another

  2 mai 2022, par user1087474

  I have two videos, that i want to concatenate side by side but second one should play after the first one is finished playing.
If the video is not playing, thumbnail should be shown

  


  Below is the example that i want to achieve using ffmpeg
https://twitter.com/sunmor2901/status/1520024861619658752

  


  I have used below command but both videos are runing simultaneously. Second, I also want to display a small text below the video describing what this video is all about (as seen in sample video link in question)

  


  ffmpeg -i 1.mp4 -i 2.mp4 \
  -filter_complex 
    "[0][1]scale2ref='ohmdar':'if(lt(main_h,ih),ih,main_h)'[0s][1s];\
     [1s][0s]scale2ref='ohmdar':'if(lt(main_h,ih),ih,main_h)'[1s][0s];\
     [0:a][1:a]amerge=inputs=2[a];[0s][1s]hstack,setsar=1" \
  -map "[a]" -ac 2 o.mp4