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• Save two video streams in one video file c#, Windows 8 application [on hold]

  19 septembre 2014, par manos

  I am developing a Windows store application which will be able to record video from two video sources (e.g. two usb cameras or usb camera and embeded tablet camera) and then save the two video streams in one video file. So, when the saved video will play, it will show a large video frame (video from camera 1) and inside that, in the top right corner, a smaller video frame (video from camera 2). Basically, i want to render one video on top of the other. I think the process is called picture in picture, but I am not 100% sure. I am able two capture the 2 video streams (same length, same video quality) but I do not know how to proceed after that. How to do the rendering. Do I save the streams into two files and then process those files or do i need to process the streams directly (merge them) and then save to file ?
  I have read that you can do something like that by using ffmpeg libraries. But so far I have not managed to find any c# code to it. Any ideas ?

  Thanks in advance,
  Manos

• Is there any way to provide different video qualities in my web application without converting each video to each format ?

  15 octobre 2019, par Dheeraj Arora

  i am building a web application which will handle thousand of videos. Currently, I am using ffmpeg to convert each video to 4 formats(1080,720,480,340px). It consumes lot of memory and time to upload for each video. Is there any best way that allows user to stream my videos in different video quality without converting each video ?

• How create a circular video (transparent area on top of video) effect without applying image mask to video

  26 septembre 2024, par Arina Lubimova

  Basically i googled a lot and solutions suggests apply some PNG mask or do not provide needed solution.

  


  What i've found.

  


  ffmpeg -i main.mkv -i facecloseup.mkv
 -filter_complex "[1]trim=end_frame=1,
  geq='st(3,pow(X-(W/2),2)+pow(Y-(H/2),2));if(lte(ld(3),pow(min(W/2,H/2),2)),255,0)':128:128,
  loop=-1:1,setpts=N/FRAME_RATE/TB[mask];
  [1][mask]alphamerge[cutout];
  [0][cutout]overlay=x=W-w:y=0[v];
  [0][1]amix=2[a]"
 -map "[v]" -map "[a]"  out.mp4


  


  command = "-i " + this.video1Path.getPath() + " -i " + this.video2Path.getPath() + " -filter_complex [1]trim=end_frame=1,geq=lum_expr='st(3,pow(X-(W/2),2)+pow(Y-(H/2),2));if(lte(ld(3)," + (this.mZoomLayout.getZoomedWidth()/2) + "*" + (this.mZoomLayout.getZoomedWidth()/2) + "),255,0)':128:128,format=gray,loop=-1:1,setpts=N/FRAME_RATE/TB[mask];[1][mask]alphamerge,format=rgba,lutrgb=a=if(gte(val\\,16)\\,val)[cutout];[0][cutout]overlay=" + this.mZoomLayout.getCircleX() + ":" + this.mZoomLayout.getCircleY() + ":enable='between(t,0," + this.videoTwoDuration + ") -c:v libx264 -crf 24 -preset ultrafast " + videoPath.getPath(); 


  


  So i tried to extract needed things from them, but i don't understand how exactly i need to do that, i did this :

  


  ffmpeg -i video.mp4 -filter_complex "[0]geq='st(3,pow(X-(W/2),2)+pow(Y-(H/2),2));if(lte(ld(3),pow(min(W/2,H/2),2)),255,0)':H:W; [0:v][mask]alphamerge" out.mp4


  


  [mov,mp4,m4a,3gp,3g2,mj2 @ 000001f761dd8e40] Invalid stream specifier: mask.
    Last message repeated 1 times
Stream specifier 'mask' in filtergraph description [0]geq='st(3,pow(X-(W/2),2)+pow(Y-(H/2),2));if(lte(ld(3),pow(min(W/2,H/2),2)),255,0)':H:W; [0:v][mask]alphamerge matches no streams.


  


  ffmpeg -i video.mp4 -filter_complex "[0]geq=lum_expr='st(3,pow(X-(W/2),2)+pow(Y-(H/2),2));if(lte(ld(3),pow(min(W/2,H/2),2)),255,0)':H:W; [0:v][mask]alphamerge" out.mp4


  


  [mov,mp4,m4a,3gp,3g2,mj2 @ 000001bfd9218e80] Invalid stream specifier: mask.
    Last message repeated 1 times
Stream specifier 'mask' in filtergraph description [0]geq=lum_expr='st(3,pow(X-(W/2),2)+pow(Y-(H/2),2));if(lte(ld(3),pow(min(W/2,H/2),2)),255,0)':H:W; [0:v][mask]alphamerge matches no streams.


  


  And one more time, guys, if you are going to post some "prepared image mask" solution - just leave, the question is about creating mask on air.

  


  So, let's say we have red square (yes, ratio is static, always 1:1), yes, i can't post it because i dont have 10 rep. (...).

  


  https://i.sstatic.net/MsL71.png - red square.

  


  https://i.sstatic.net/aIFEV.png - circle

  


  https://i.sstatic.net/R8EAx.png - result

  


  https://i.sstatic.net/WtqQg.png - final result

  


  I actually want to get the answer from @Gyan or @llogan because i searched a lot and only these two guys do understand how to make things programmatically.

  


  More tech details :
Aspect ratio is constant - 1:1, width and height should be taken from the video in auto way, we need to create a white square with transparent circle inside it, the end result must contain "rounded" video with white background.