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• openCV image Stitching wide angle 160 degrees

  4 janvier 2020, par a.masri

  I’m trying to Stitching image wide angle 160.5 degree but the result is not a good

  i’m using OpenCV 4 and ffmpeg to get frames from video

  ffmpeg command to get 15 frame per sec :

  ffmpeg -i first.mp4 -vf fps=15  preview%05d.jpg

  OpenCV Stitching code

  import cv2
  
  import numpy as np
  
  
  
  images = []
  
  for i in range(70):
  
      name = ('preview%05d.jpg' % (i+1))
  
      print(name)
  
      images.append(cv2.imread(name , cv2.IMREAD_COLOR))
  
  
  
  
  
  print("start ")
  
  stitcher = cv2.Stitcher_create()
  
  ret, pano = stitcher.stitch(images)
  
  
  
  if ret == cv2.STITCHER_OK:
  
      cv2.imshow('panorama', pano)
  
      cv2.waitKey()
  
      cv2.destroyAllWindows()
  
  else:
  
      print(cv2.STITCHER_ERR_NEED_MORE_IMGS)
  
      print(cv2.STITCHER_ERR_HOMOGRAPHY_EST_FAIL)
  
      print(cv2.STITCHER_ERR_CAMERA_PARAMS_ADJUST_FAIL)
  
      print(ret)
  
      print('Error during stiching')

  actual result :

  

  expected result :

  

• Overlaying a list of video files on top of another list of video files

  2 août 2023, par sybr

  I'm currently working on a way to improve my production process for the videos that I'm making. The source files consist of a list of two side-by-side clips that I handpick and stitch together in Premiere Pro. I recently came across FFmpeg and thought, 'surely there's a way to automate the rendering of these videos'.

  


  I've managed to get the general overlay working, where I have one clip overlaid on top of the other one, but the overlaid clip doesn't have any audio, and the overlaid clip currently doesn't scale to the height of the background clip.

  


  Here's what i'd like it to look like :


  


  As illustrated in the image, I want to overlay the overlay clip on top of the background clip, preserving audio for both clips, and shift the background clip's position to the right by 33%. Now, instead of both "clips" being just one clip, I want to use two folders with each about 1 hour's worth of clips to compile an hour-long video containing both folders.

  


  Is there a way to achieve what I want to do here ? Or would it make more sense to compile two separate videos first by concatenating all videos in their respective folders first, and then overlaying one video on top of the other one ?

  


  Would love some help here, also eager to learn more about FFmpeg, so some explanation would be highly appreciated !

  


• Using Mencoder to Convert Sequence of Images Sorted Numerically to Video

  7 décembre 2017, par txizzle

  I want to use mencoder to convert a sequence of PNG files to video. The PNG files are named like file1.png, file2.png, ... file1000.png. However, if I run this :

  mencoder mf://*.png -mf fps=25 -ovc copy -oac copy output.avi

  The resulting video will not stitch together the frames in the correct order (correct : 1,2,3,.... incorrect : 1, 10, 100, ...). Answers to a similar question suggest that I can manually input the range of frames to have mencoder use the correct numerical order :

  mencoder mf://file{1..1000}.png -mf fps=25 -ovc copy -oac copy output.avi

  or to manually sort the files with something like ls -v and then save the results to a list (say, list.txt), and then pass that into mencoder :

  mencoder mf://@list.txt -mf fps=25 -ovc copy -oac copy output.avi

  However, my question is : Is there a way to do this in a single command without specifying the last frame ?

  Ideally, I would want an equivalent to mf://file*.png that uses a numerical sorting as opposed to the default sorting. For example, ffmpeg has the option to specify input files like file%d.png, which would order the files numerically.

  Thanks !