Recherche avancée

Sur d’autres sites (5787)

• ffmpeg mp4 cut from correct point | without encode

  3 mars 2018, par sword1st

  I’m using this this command for cut my mp4 video :

  ffmpeg -i clip.mp4 -ss 00:00:25 -to 00:01:20 -c copy cutted.mp4

  But there is a problem with this code. My "cutted" clip has black video for a couple seconds and it’s have sync problem on editing software. When i tweak the first parameter -ss like 00:00:24 ... 00:00:23 .... 00:00:26 etc when i found the right position it doesn’t have any black frame or sync problem. I want to learn how can i learn all of this correct times for my video ? I don’t know what should i call these points. Gop or anything else. Is there any solution built-in ffmpeg to learn this times so i can cut them without any corruption ? Thanks !

• Add metadata to flv files with ffmpeg instead of flvmdi

  30 juillet 2012, par user1476852

  I have made a player for stream flv movies in flash with netstream but it needs some metadata information named " keyframe " containing two array of times and positions , some flv videos have this meta data and some not , i could add the keyframe metadata with a program named "flvmdi" and player worked properly , but i can`t install this software on my server for some reasons.
  I know that we can add metadata to a movie with ffmpeg function in PHP .
  Can i use ffmpeg function in PHP to add keyframe arrays as metadata to flv file ?
  How can we make times and positions arrays to inject to a flv file with ffmpeg in php ?

• Imageio unable to read webcam at correct framerate

  28 mai 2019, par Jason Nick Porter

  I’m trying to read frames from a webcam and analyze them in realtime, but since my function AnalyzeFrame() is faster than the framerate, it ends up pulling the same frame 1-4 times in a row, messing up my data. Here’s basically what I’m running.

  import imageio
  
  
  
  cam = imageio.get_reader('<video0>', fps=30)
  
  
  
  while not cam.closed:
  
      print(AnalyzeFrame(cam.get_next_data()))
  
  </video0>

  A few notes : My webcam should be able to handle 30fps, but I’m averaging 12-14 fps. I’ve timed each individual process and there’s very little regularity to the framerate. Some frames only get analyzed once, because they’re in the buffer for 20 or so milliseconds. Others get analyzed 4 times over a span of 100+ ms. Is there something in my code that’s causing this framerate problem ?