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• How to fetch both live video frame and timestamp from ffmpeg to python on Windows

  8 mai 2018, par vijiboy

  Searching for an alternative as OpenCV would not provide timestamps for live camera stream (on Windows), which are required in my computer vision algorithm, I found ffmpeg and this excellent article https://zulko.github.io/blog/2013/09/27/read-and-write-video-frames-in-python-using-ffmpeg/
  The solution uses ffmpeg, accessing its standard output (stdout) stream. I extended it to read the standard error (stderr) stream as well.

  Working up the python code on windows, while I received the video frames from ffmpeg stdout, but the stderr freezes after delivering the showinfo videofilter details (timestamp) for first frame.

  I recollected seeing on ffmpeg forum somewhere that the video filters like showinfo are bypassed when redirected. Is this why the following code does not work as expected ?

  Expected : It should write video frames to disk as well as print timestamp details.
  Actual : It writes video files but does not get the timestamp (showinfo) details.

  Here’s the code I tried :

  import subprocess as sp
  
  import numpy
  
  import cv2
  
  
  
  command = [ 'ffmpeg', 
  
              '-i', 'e:\sample.wmv',
  
              '-pix_fmt', 'rgb24',
  
              '-vcodec', 'rawvideo',
  
              '-vf', 'showinfo', # video filter - showinfo will provide frame timestamps
  
              '-an','-sn', #-an, -sn disables audio and sub-title processing respectively
  
              '-f', 'image2pipe', '-'] # we need to output to a pipe
  
  
  
  pipe = sp.Popen(command, stdout = sp.PIPE, stderr = sp.PIPE) # TODO someone on ffmpeg forum said video filters (e.g. showinfo) are bypassed when stdout is redirected to pipes??? 
  
  
  
  for i in range(10):
  
      raw_image = pipe.stdout.read(1280*720*3)
  
      img_info = pipe.stderr.read(244) # 244 characters is the current output of showinfo video filter
  
      print "showinfo output", img_info
  
      image1 =  numpy.fromstring(raw_image, dtype='uint8')
  
      image2 = image1.reshape((720,1280,3))  
  
  
  
      # write video frame to file just to verify
  
      videoFrameName = 'Video_Frame{0}.png'.format(i)
  
      cv2.imwrite(videoFrameName,image2)
  
  
  
      # throw away the data in the pipe's buffer.
  
      pipe.stdout.flush()
  
      pipe.stderr.flush()

  So how to still get the frame timestamps from ffmpeg into python code so that it can be used in my computer vision algorithm...

• How can I get a thumbnail from a video that a user has uploaded to my server ?

  27 novembre 2013, par user3041398

  I'm working on a video sharing website where people can upload their own videos and I want the most recent uploads to be shown on the index page, but not as videos but thumbnails, so that when you click on the thumbnail you get to the video page. You guys all know how youtube's index looks/works — that's what I'm trying to simulate.

  I read about ffmpeg but it seems to me it would only work if you have ffmpeg installed on your computer. I want this to be an automated process though without the user having to first install something on their pc.
  Is there a way I can code this ? Or do i have to use some kind of framework or CMS ? Could this problem be solved by simply getting ffmpeg hosting (example) ?
  If there is no manual way to do this in php, is there way using python ?

  Fyi, my website is written in php and i use jwplayer to stream the videos.
  Please note that I want to get a thumbnail from a video that's been uploaded on my server and not a youtube or vimeo thumbnail.

• ffprobe File not fournd error due long path BUT windows long path enabled

  10 novembre 2020, par nonayme

  I have a python program which run ffprobe on some videos on my win10 computer, and its working fine for most of them. The buggy ones have pretty long path, which seems to be the issue despite a "No Such file or Directory" message from ffprobe, this because :

  


  

  • I checked the path and it exists

  


  • In cmd when I mannualy cd to the directory and start ffprobe -i autocompletion complete with the right name

  


  • Windows Sub-system Linux achieve to run ffprobe from my copy pasted path extracted from my program

  


  


  => the file exist

  


  

  • I made a copy of my file and renamed it with a longer name than the buggy one (ffprobe doesn't work), and also with a really short name (ffprobe works)

  


  


  => path size is the culprit
BUT I have enabled long path on both the registry AND the group policy... any ideas ?