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• How to append an image to a video using OpenCV or FFMPEG or Moviepy or other libraries ?

  19 juillet 2022, par Trần Tiến Văn

  Do you know a library in Python to add a frame image to an existing video ? The result video must have the same quality as the image.

  


  I tried to use OpenCV to add google image : https://www.google.com/search?q=google&sxsrf=ALiCzsZhrdoHnOTmg0We4dxtguCqzma5Jg:1657603343101&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiTh8bTzfL4AhWhplYBHfXNAKwQ_AUoAXoECAIQAw&biw=1492&bih=739&dpr=1.25#imgrc=PRtenhDnrVrfOM

  


  But the quality decreases when the video elongates.

  


  Here is the final result video : https://drive.google.com/file/d/1ArDvoX-kN9H_oLbACk3kU1Cid93SMczC/view?usp=sharing

  


  Here is my code using OpenCV :

  


          image = cv2.imread(path_image)
        height, width, dimensions = image.shape
            
        video = cv2.VideoCapture(path_video)
        
        
        frames = []
        while(True):
            
            ret, frame = video.read()
            
            if ret == True: 
                frames.append(frame)
                # frame = frame.resize(frame, (width, height), fx=0, fy=0, interpolation = cv2.INTER_CUBIC)
                
                # Press S on keyboard 
                # to stop the process
                if cv2.waitKey(1) & 0xFF == ord('s'):
                    break
            # Break the loop
            else:
                break
            
        video2 = cv2.VideoWriter(path_video,cv2.VideoWriter_fourcc('M','J','P','G'), 30, (width, height))
        for frame in frames:
            video2.write(frame)
        video2.write(image)
        video2.release()  # releasing the video generated     
        print("Added {}".format(image_name))


  


  I hope to improve the quality of this video.

  


• Screen Recording Issues using Python and FFMPEG [closed]

  3 juin, par Kevin McDowell

  I am trying to record a walkthrough of a 3D space contained within a Chrome browser session. The goal is to create deterministic output. If I run this command from a VS Code terminal, it records 30 seconds of video from the window that's about 6MB :

  


  ffmpeg -f gdigrab -framerate 30 -i "title=My3D - Google Chrome" -t 30 "My3D - Google Chrome_screenRecording_v0.mp4"


  


  However, if I call it from Python like so :

  


  subprocess.run("ffmpeg -f gdigrab -framerate 30 -i \"title=My3D - Google Chrome\" -t 15 \"My3D - Google Chrome_screenRecording_v0.mp4\"")


  


  The output video is 30 seconds, but while I can see the mouse moving on the screen, the image is all black and the filesize is only 94KB.

  


  This is on a Windows 11 machine with GPU acceleration disabled in the OS as well as in Chrome. I've also tried it with other web pages and those are also recorded black. Any ideas what is causing this or how to record the screen using Python ?

  


  I've got other alternatives working (using Selenium or PyGet to capture screenshots and then using the VideoWriter class from OpenCV to write them to a video file), but that has a limitation of only about 10 FPS and you can't control the recording time like you can with FFMPEG. If you screen capture for 30 seconds, the actual output may only be 12-18 seconds.

  


• How to improve the animation quality with ffmpeg ?

  17 janvier 2017, par Loïc Poncin

  With ffmpeg I was able to get animation as an MP4 file and then I converted it into a GIF file.

  # Animation
  
  ani = animation.ArtistAnimation(fig, film, interval=100, blit=True, repeat_delay=100)
  
  ani.save('animation.mp4', writer="ffmpeg", fps=30)
  
  
  
  os.system("ffmpeg -i C:\my_path\\animation.mp4 C:\my_path\\animation.gif")

  My problem is that the quality is not really good.

  In my google drive (https://drive.google.com/open?id=0B7P95aWmH4DUbzJCaVZQM3Y0Y1U) you can find 3 files showing the animation : 1 PNG image (good quality), 1 MP4 file (normal quality), 1 GIF file (bad quality).

  How can I keep a good quality during the process ?