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• How can I send a virtual camera to Genymotion or Android Studio Emulator in Ubuntu ?

  4 décembre 2020, par ykasur

  I created a virtual camera using v4l2loopback and ffmpeg. The command I use for ffmpeg is :
ffmpeg -re -l oop 1 -i vin.png -vf format=yuv420p -f v4l2 /dev/video2

  


  vin.png is the image I want to stream to the webcam and /dev/video2 is the virtual webcam I created with v4l2loopback.
The virtual webcam works and I can see it e.g. with onlinemicetest.com/webcam-test.
I'm using the Genymotion emulator with the newest Android API (I tried 7.0, 8.1 and 10.0) on Ubuntu 20.40.
Genymotion detects the virtual camera but only displays a dummy image :
Wrong dummy Image from Genymotion
I also tried (and would prefer to use) the android studio emulator. But I can only select Webcam0 in the configuration of the device camera and that points to the real integrated camera and not to my virtual webcam.

  


  I don't need to use ffmpeg, but I do need to use a tool that lets me control which image to stream from the command line.

  


  Is there a way to solve this ? Many thanks in advance !

  


  Update 17.11.2020 :
The Genymotion support answered me, that they plan to support virtual cameras in the future. They might be ready to add this in mid 2021.

  


• flutter FFMPEG concat not working properly with camera recorded clips

  27 février 2024, par ibrahim Eltayfe

  I am using the Flutter camera package to record videos, I record multiple videos and then concatenate them using this command :

  


  


  "-y -f concat -i $videosPathsTextFilePath -c:a aac -c:v copy $fullVideoOutPath",

  


  videosPathsTextFilePath content is :
  
file 'record-1709022968582.mp4'
  
file 'record-1709022976601.mp4'

  


  


  when I record with one side only like the camera back side and concatenating the clips, it works as expected, but when I change the camera side and then concat the clips, the clip recorded after changing the camera side is shown rotated upside down as -90

  


  I checked the clips from Device Explorer, it is all right, but after the concatenation it shows flipped.

  


  here are the two videos before concatenation :

  


  https://imgur.com/a/MVkEDm3
  
https://imgur.com/Kit1J8V

  


  and this is the video after concatenating :
  
https://imgur.com/6CAxN05

  


  Thank you in advance.

  


  I tried to check if the user changed the camera side to track the clips recorded by this side then rotate them and move them to another directory but this command is not working

  


  -noautorotate -display_rotation 90 -i ${videoFile.path} -c:v copy ${destinationPath}

  


• opencv open camera and ffmpeg open Microphone

  6 janvier 2017, par H S T

  I use opencv open camera and obtain video and push stream. Then I want add audio and push it. When I use ffmpeg function

  avformat_open_input(&ifmt_ctx, psDevName, ifmt, NULL),
  
  program break.

  So can I use opencv open camera and use ffmepg open Microphone ?

  I want to write anchor push streaming client and must use opencv open camera.