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• Adding transparency to a video from black and white (and gray) alpha information video images

  3 juillet 2018, par Jan F.

  I’d like to create a video with transparency (and semi transparency) in android. The images of the source video are split into two images, the top one with color information (looks like the normal video image), the bottom one with alpha information (the same shapes but only in black and white and gray, black means transparent).

  This is the solution for iOS :
  https://medium.com/@quentinfasquel/ios-transparent-video-with-coreimage-52cfb2544d54

  What would be the best way to to this in android ?

  Can this be solved with javacv, FFmpegFrameGrabber, FFmpegFrameFilter etc.?

  Or better with OpenGL ES and shaders ?

  Are there any samples ?

  Thanks !

• Append A Frame (PNG) FFMPEG To existing video, Make changes all the video - libx264

  7 décembre 2022, par agh bagherian

  I want to append a frame to existing video by using ffmpeg.

  


  p0.png, p1.png and p2.png (3 frames)

  


  by this command ffmpeg generate first video :

  


  ffmpeg -framerate 4 -f image2 -s 1280x720 -i p%d.png -vcodec libx264 -b 80k test1.mp4

  


  Then i want to append a frame to last of video, but total video in HEX-View will be changed. I use this command to append :

  


  ffmpeg -framerate 4 -f image2 -s 1280x720 -t 1 -i new_pic.png -i test1.mp4 -vcodec libx264 -b 80k test2.mp4

  


  Please see image below :

  


  Please see this screen shot

  


  But i want only append some hex code to end of first video....

  


  Please help me. Thanks

  


  I tried many commands. I did not get any results

  


• Problems in making Video from Lottie JSON File and Overlay it with original video using FFMPEG

  26 juin 2019, par Krishna Vyas

  there is some unique concept about processing Lottie Animations using FFMPEG video processing library and MediaCodec. In that, I wants to make video from Lottie animation and overlay that video on other original video.

  But the problem is i’m unable to make a video with transparent background from Lottie animation. So i made simple video from Lottie animation using MediaCodec and MediaMuxer, it takes one by one frame from Lottie Drawable and attach it to the video(Lottie Video). Here is the link about this concept- https://engineering.21buttons.com/how-to-generate-videos-using-lottie-in-android-2db6ecceb2a

  And then i overlay this video to the original video using FFmpeg library. Here FFmpeg does two task, first it makes transparent background in Lottie Video and second it overlays this Lottie Video above the original video.

  And here the actual problem is out, FFmpeg takes more than 8 to 9 minutes in processing of video of 25 seconds, So i wants to get solution for this problem, as i have time limit of only 1 to 2 minutes. Any one has a solution for it or new ides for implementation of this concept, then please tell me i’ll appreciate it.