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• ffmpeg - overlay a video with rounded corners

  4 novembre 2019, par asi

  I am successfully using overlaying a scaled (smaller) video on top of a larger one but am struggling to understand how could I give the small video a rounded corners mask.

  Edit

  thanks to @loogan comment I’ve managed to get a working command that created applies a circular mask :

  ffmpeg 
  
      -i main.mp4 
  
      -i vignette.mp4 
  
      -filter_complex 
  
        [1:v]scale=300:-1[scaled];
  
        [scaled]split [scaled0][scaled11]; 
  
        [scaled0]trim=end_frame=1,geq='st(3,pow(X-(W/2),2)+pow(Y-(H/2),2));if(lte(ld(3),780*780),255,0)':3:3,loop=-1:1,setpts=N/FRAME_RATE/TB[mask];
  
      [scaled1][mask]alphamerge[cutout];
  
      [0][cutout]overlay=x=W-w:y=0[v];
  
      -map [v] 
  
      -map [a]  
  
      output.mp4

  but how to get from a circle to a rounded rect still eludes me. cant quite get what are the params that geq expects and the math to generate them.

  assuming that the video that needs masking is 200 * 300 and the corners should have a 5px radius, is there a geq command that can create this mask ? maybe en ellipse ?

  or maybe a better way would be to use a pre-made png as a mask ?

  any insights welcome

• ffmpeg to cut beginning and fade in audio

  31 juillet 2024, par cannyboy

  I've got a bunch of spoken word mp3 files, which all have the same intro talking and music, and then the real content begins. So it goes roughly like this :

  


  00:00 Standard intro spoken word
00:20 Standard intro music
00:35 The content


  


  The timings are not always the same (can vary by 5 secs). So I'd to cut the first 25 seconds and then fade in the next five seconds. And then output the file in the same mp3 format. Is this possible with ffmpeg ?

  


• Merge individual frame to video file using Opencv and FFmpeg

  16 août 2022, par Rohit

  I am trying to stack a individual frame to a video file using Opencv. I want to combine two different code together to make the individual frame.
Following code help me extract the individual frame

  


  while True:
ret, frame=cap.read()
mask = object_detector.apply(frame)
_, mask  = cv2.threshold(mask,254,255,cv2.THRESH_BINARY)       
contours,_ = cv2.findContours(mask, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
res = cv2.bitwise_and(frame,frame,mask=mask)
for cnt in contours:
    area = cv2.contourArea(cnt)
    if area>1000:   
        #print("Area of contour:", area)
        cv2.drawContours(frame, [cnt], -1, (0,255,0),2)
        cv2.imwrite("file%d.jpg"%count, frame)


  


  And I attach the frame together separately using following code using ffmpeg command

  


  ffmpeg -r 3 -i frame%03d.jpg -c:v libx264 -vf fps=25 -pix_fmt yuv420p video.mp4


  


  I tried storing the individual frame in array, but it didn't work. It doesn't show any error, but pc crash.