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• frame extracted from a video using opencv or ffmpeg is vague, picture i snip from video is clear

  15 avril 2024, par user11317826

  I record a video from roadside, and I want to recognize plate license in video. but I find that if I extract every frame from video using python, the frame is too vague to recognize.

  


  I have tried opencv and ffmpeg -i input.mp4 -ss 00:00:10.000 -vframes 1 output.png
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  but if I snip video every second the picture is clear

  


  

  


  what's the reason of this phenomenon, how can I fix it

  


  I have tried frame average, it didn't work

  


• ffmpeg : how to convert iphone4 720p video into similar quality Flash video ?

  5 septembre 2011, par Sajee

  What are the proper arguments to ffmpeg to covert an iphone4 720p video into the similar quality Flash video ?

  I tried the following which resulted in a low quality Flash video :

  ffmpeg movie.mov movie.flv

  What are the right switches ?

• What is the accurate way of calculating SSIM score (with ffmpeg) between a video stream and the reference video ?

  22 mars 2016, par krishna222

  As ffmpeg calculates ssim score by a frame-by-frame comparision,
  how do I exactly align the reference video (say ref.mp4) with the video stream, so that only the corresponding frames (ith frame of both the videos, for all i) are compared by ffmpeg ? Please help.