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• How to replace the video track of a part of a video file ?

  17 juin 2019, par yukashima huksay

  I have an mp4 file like this(same format but longer) :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'N1.2.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: mp42mp41
  
      creation_time   : 2018-10-31T13:44:21.000000Z
  
    Duration: 00:28:54.21, start: 0.000000, bitrate: 10295 kb/s
  
      Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 9972 kb/s, 50 fps, 50 tbr, 50k tbn, 100 tbc (default)
  
      Metadata:
  
        creation_time   : 2018-10-31T13:44:21.000000Z
  
        handler_name    : ?Mainconcept Video Media Handler
  
        encoder         : AVC Coding
  
      Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 317 kb/s (default)
  
      Metadata:
  
        creation_time   : 2018-10-31T13:44:21.000000Z
  
        handler_name    : #Mainconcept MP4 Sound Media Handler

  I also have another video file that is 3 minutes long. and has no audio. What is the fastest way to encode the other video in a way that it is encoded like my main video and then replace the last three minutes of the video track of my original video with this ?

  In other words.
  I have video A that is 1 hour long. With the encoding shown above.

  I have video B that is 3 minutes long with no audio. with a random encoding.

  I want to have video C with the same encoding and same audio as A. But it’s video track would be the first 57 minutes of A + B(which is 3 minutes).

  I want to do this as fast as possible so I would like to not re encode A.

  I know how to concatenate two videos, I use this command :

  ffmpeg -f concat -i files.txt -c copy res.mp4

• 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
`

  


  

  


  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 ?