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• OpenCv is giving error to play the downloaded video

  17 août 2015, par Prat_yow

  Program a code for a tiny system, which should run on Linux :
   A routine (P) accepts strings from an unknown remote Internet source,
  which contain just an URL and a file name.
   The URL and the file name point to a multimedia file, in our case a video
   (P) separates the file name from the string
   (P) checks if the file already exists on the system’s internal memory card, as
  (P) is running on a tiny Linux machine connected to a screen
   If it does not exist, (P) downloads the video file from the given URL and
  stores it in the memory card
   Finally, (P) opens the file and plays it as a full screen video (no external video
  player allowed !)
   After this (P) starts from the beginning
   There is no user action involved and nobody enters data by hand or mouse
  clicks

  I have written code in python. But when I run it it just not load the cv module. Can someone suggest if my approach is correct.? Will doing in java or other compiled language will be easy.?

  My code is :

  import os
  
  import urllib
  
  import cv
  
  import sys
  
  
  
  """
  
  The following program will take the url as input. Separate the file name of the video from the url
  
  and check if the file is present in the current memory location or not. If the same file is present
  
  it will indicate its presence. If the file is not present it will download the file and play it.
  
  
  
  urrlib: to download the video file.
  
  cv: For playing the video.
  
  
  
  """
  
  
  
  #NOTE Configuration of FFMPEG and OpenCV  is required. 
  
  #NOTE Assuming that the given code is execute from the internal memory location.
  
  #NOTE Assuming the URL is of the form <initial part="part" of="of" the="the" url="url"></initial><filename>.<format>
  
  
  
  sys.path.append('/opt/ros/hydro/lib/python2.7/dist-packages')
  
  
  
  def myVideo(url):
  
      search_folder = "."
  
      videoFile = url.split('/')[-1].split('#')[0].split('?')[0] #stripping the name of the file.
  
  
  
      for root, dirs, files in os.walk(search_folder): # using the os.walk module to find the files.
  
          for name in files:
  
              #print os.path.join(name)
  
  
  
              """Checking the videofile in the current directory and the sub-directories"""
  
  
  
              if videoFile == os.path.join(name):  #checking if the file is already present in the internal memory.
  
                  print "The file is already present in the internal memory"
  
                  return -1  # Returning the confirmation that the file is present.
  
  
  
              else:
  
                  print "Downloading the file"
  
                  video = urllib.FancyURLopener() #downloading the file using urllib.
  
                  video.retrieve(url,videoFile)
  
  
  
                  curDir = os.getcwd()   # getting the current working directory.
  
                  fullVideoPath = os.path.join(curDir,videoFile)  # Making the full path of the video file.
  
  
  
                  """For playing the file using openCV first read the file.
  
                  Find the number of frames and the frame rate.
  
                  Finally use these parameters to display each extracted frame on the screen""" 
  
  
  
                  vFile = cv.CaptureFromFile(fullVideoPath)
  
                  nFrames = int(  cv.GetCaptureProperty( vidFile, cv.CV_CAP_PROP_FRAME_COUNT ) ) #Number of frames in the video.
  
                  fps = cv.GetCaptureProperty( vidFile, cv.CV_CAP_PROP_FPS ) # Frame rate
  
                  waitPerFrameInMillisec = int( 1/fps * 1000/1 ) # Wait time between frames.
  
  
  
                  for f in xrange( nFrames ):
  
                      frameImg = cv.QueryFrame( vidFile )
  
                      cv.ShowImage( "My Show",  frameImg )
  
                      cv.WaitKey( waitPerFrameInMillisec  )
  
  
  
                  cv.DestroyWindow( "My Show" ) # Deleting the window once the playing is done.
  
                  return 1 # returning the confimation that the file was played successfully.
  
  
  
  if __name__ == "__main__":
  
      url = "http://techslides.com/demos/sample-videos/small.mp4"
  
      myVideo(url)
  
  </format></filename>

• How can I reencode a video to match another's codec exactly ?

  24 janvier 2020, par Stephen Schrauger

  When I’m on vacation, I usually use our camcorder to record videos. Since they’re all the same format, I can use ffmpeg to concat them into one large, smooth video without re-encoding.

  However, sometimes I will use a phone or other camera to record a video (if the camcorder ran out of space/battery or was left at a hotel).

  I’d like to determine the codec, framerate, etc used by my camcorder and use those parameters to convert the phone vidoes into the same format. That way, I will be able to concatonate all the videos without re-encoding the camcorder videos.

  Using ffprobe, I found my camcorder has this encoding :

    Input #0, mpegts, from 'camcorderfile.MTS':
  
    Duration: 00:00:09.54, start: 1.936367, bitrate: 24761 kb/s
  
    Program 1 
  
      Stream #0:0[0x1011]: Video: h264 (High) (HDPR / 0x52504448), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], 59.94 fps, 59.94 tbr, 90k tbn, 119.88 tbc
  
      Stream #0:1[0x1100]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, fltp, 256 kb/s
  
      Stream #0:2[0x1200]: Subtitle: hdmv_pgs_subtitle ([144][0][0][0] / 0x0090), 1920x1080

  The phone (iPhone 5s) encoding is :

    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'mov.MOV':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2017-01-02T03:04:05.000000Z
  
      com.apple.quicktime.location.ISO6709: +12.3456-789.0123+456.789/
  
      com.apple.quicktime.make: Apple
  
      com.apple.quicktime.model: iPhone 5s
  
      com.apple.quicktime.software: 10.2.1
  
      com.apple.quicktime.creationdate: 2017-01-02T03:04:05-0700
  
    Duration: 00:00:14.38, start: 0.000000, bitrate: 11940 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 11865 kb/s, 29.98 fps, 29.97 tbr, 600 tbn, 1200 tbc (default)
  
      Metadata:
  
        creation_time   : 2017-01-02T03:04:05.000000Z
  
        handler_name    : Core Media Data Handler
  
        encoder         : H.264
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 63 kb/s (default)
  
      Metadata:
  
        creation_time   : 2017-01-02T03:04:05.000000Z
  
        handler_name    : Core Media Data Handler
  
      Stream #0:2(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
  
      Metadata:
  
        creation_time   : 2017-01-02T03:04:05.000000Z
  
        handler_name    : Core Media Data Handler
  
      Stream #0:3(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
  
      Metadata:
  
        creation_time   : 2017-01-02T03:04:05.000000Z
  
        handler_name    : Core Media Data Handler

  I’m presuming that ffmpeg will automatically take any acceptable video format, and that I only need to figure out the output settings. I think I need to use -s 1920x1080 and -pix_fmt yuv420p for the output, but what other flags do I need in order to make the phone video into the same encoding as the camcorder video ?

  Can I get some pointers as to how I can translate the ffprobe output into the flags I need to give to ffmpeg ?

  Edit : Added the entire Input #0 for both media files.

• Official Piwik Training in Berlin – 2014, June 6th

  6 mai 2014, par Piwik Core Team — Community

  This event will focus on providing training to users of the Piwik analytics platform. The training will provide attendees with the necessary skills and knowledge that they will need to be able to take their website to the next level with Piwik.

  Language : English

  Register to Piwik Training now.

  Location : The 25hours Hotel Bikini Berlin is as diverse as the big city it is located in and as wild as a jungle. The hotel showcases cosmopolitan Berlin at its location in the listed Bikini-Haus building between the Tiergarten park and Breitscheidplatz with Kaiser Wilhelm Memorial Church.

  

  Why do you need training ?

  If you have just started using Piwik and are finding it a bit overwhelming, this training event will benefit you immensely. You will be able to learn all the necessary skills that will allow you move forward with Piwik.

  For users who have been using Piwik for a short time and have a bit of experience in using Piwik, you will be able to learn how to advance your skills and extend your knowledge of the Piwik platform.

  Advanced users will be able to gain more knowledge about the complex features and functions that Piwik incorporates, allowing you to customise different areas of the platform and learn about advanced topics.

  How can you benefit from this training event ?

  By understanding how Piwik works and how to use and operate Piwik more effectively, you will be able to make sound changes to your website that will allow you to achieve your business goals.

  Everyone, from ecommerce businesses to government organisations can benefit from this training event and learn the essential skills and gain the relevant knowledge to meet their goals and requirements.

  Some of the skills that you will learn during the training include :

  • How to install and get started with the Piwik platform
  • How Piwik will add value to your website
  • How to analyse and make sense of the data and information that you collect
  • How to create custom segments that will allow you to report on certain data and information
  • Advance exercises – Piwik settings, tweaking and basic diagnostics

  What equipment do I need in order to participate in the event ?

  You will need a computer that is able to connect to a Wifi network

  Are the tickets transferable ?

  Yes, the tickets are transferable.

  What is the refund policy on the tickets ?

  You are entitled to a refund up to 1 week before the commencement of the training.

  Training details

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  Contact us : contact@piwik.pro

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  Register to Piwik Training now !