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• Extract specific frames of youtube video without downloading video

  22 janvier 2023, par Kashish Arora

  I need to extract specific frames of an online video to work on an algorithm but I don't want to download the whole video because that would make it highly inefficient.

  


  For starters, I tried working with youtube videos. I can download whole of the video using youtube-dl in this way :

  


  ydl_opts = {'outtmpl': r'OUTPUT_DIRECTORY_HERE',}
with youtube_dl.YoutubeDL(ydl_opts) as ydl:
    ydl.download([url])


  


  And then I can capture individual frames.

  


  I need to avoid downloading the whole video. After some research, I have found that ffmpeg might help me do this. I found no way to download just the frames so if this is not possible, the second option is that I can download specific portions of the video. One such example in linux is here but I couldn't find any solution for python.

  


  What is a good way to download just the frames, or portions of videos (in python) without downloading the entire thing ?

  


• Python : How to use ffmpeg to read videos(video file or rtsp) and display them using OpenCV ?

  22 août 2019, par ToughMind

  I know that if we want to read video file or USB camera or rtsp stream, we can use cv2.VideoCapture.
  But for some reason, I want to use ffmpeg to do the thing and process obtained images using opencv. So the pseudocode would be :

  import cv2
  
  import ffmpeg
  
  
  
  videoFile = 'XXX.mp4'
  
  
  
  video = ffmpeg.XXX(videoFile)
  
  
  
  while True:
  
      frame = video.read() # this read() function is made up by me
  
      frameCV = ffmpeg2cv(frame) # this ffmpeg2cv() function is made up by me
  
  
  
      cv2.imshow('frame', frameCV)

  I have searched a something like https://github.com/kkroening/ffmpeg-python. But I still not know how to do this. I think ffmpeg is too hard and there are few online docs unlike opencv. So please help.

• How to change ffmpeg -threads settings [migrated]

  5 août 2014, par Jacob

  Working on a tube site. I’m running videos through ffmpeg on a linux dedicated server to convert to mp4.

  The server specs :

  Architecture:          x86_64
  
  CPU op-mode(s):        32-bit, 64-bit
  
  Byte Order:            Little Endian
  
  CPU(s):                8
  
  On-line CPU(s) list:   0-7
  
  Thread(s) per core:    2
  
  Core(s) per socket:    4
  
  Socket(s):             1
  
  NUMA node(s):          1
  
  Vendor ID:             GenuineIntel
  
  CPU family:            6
  
  Model:                 60
  
  Stepping:              3
  
  CPU MHz:               3491.749
  
  BogoMIPS:              6983.49
  
  Virtualization:        VT-x
  
  L1d cache:             32K
  
  L1i cache:             32K
  
  L2 cache:              256K
  
  L3 cache:              8192K
  
  NUMA node0 CPU(s):     0-7

  Issue during testing is that even only doing 4-5 at once, the server load skyrockets to an average of around 36. This is just a single person. I imagine when it opens, many people will be uploading at once.

  It seems ffmpeg tries to use all the resources available per conversion.

  I’ve heard there’s a -threads setting you can change, but I cannot find it. I have an 8 cpu server. It’s only used for conversions, so I’ve heard the best setting would be between 2 and 4. I can test it out.

  But how do I change this setting ? Everything I see online discusses this setting, but not the steps to change it.