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• Live stream is gets delayed while processing frame in opencv + python

  18 mars 2021, par Himanshu sharma

  I capture and process an IP camera RTSP stream in a OpenCV 4.4.0.46 on Ubuntu.
Unfortunately the processing takes quite a lot of time, roughly 0.2s per frame, and the stream quickly gets delayed.
Video file have to save for 5 min but by this delaying video file is saved for 3-4 min only.

  


  Can we process faster to overcome delays ?

  


  I have two IP camera which have two diffrent fps_rate(Camera 1 have 18000 and camera 2 have 20 fps)

  


  I am implementing this code in difference Ubuntu PCs

  


  

  • Python 3.8.5 (default, Jul 28 2020, 12:59:40) [GCC 9.3.0] on linux

  


  • Django==3.1.2

  


  • Ubuntu = 18.04 and 20.04

  


  • opencv-contrib-python==4.4.0.46

  


  • opencv-python==4.4.0.46

  


  


  input_stream = 'rtsp://'+username+':'+password+'@'+ip+'/user='+username+'_password='+password+'_channel=0channel_number_stream=0.sdp'
input_stream---> rtsp://admin:Admin123@192.168.1.208/user=admin_password=Admin123_channel=0channel_number_stream=0.sdp

input_stream---> rtsp://Admin:@192.168.1.209/user=Admin_password=_channel=0channel_number_stream=0.sdp

vs = cv2.VideoCapture(input_stream)
fps_rate = int(vs.get(cv2.CAP_PROP_FPS))
I have two IP camera which have two diffrent fps_rate(Camera 1 have 18000 and camera 2 have 20 fps)

video_file_name = 0
start_time = time.time()
while(True):
    ret, frame = vs.read()
    time.sleep(0.2)     # <= Simulate processing time (mask detection, face detection and many detection is hapning)


    ###  Start of  writing a video to disk          
    minute = 5  ## saving a file for 5 minute only then saving another file for 5 min
    second  = 60
    minite_to_save_video = int(minute) * int(second)


    # if we are supposed to be writing a video to disk, initialize
    if time.time() - start_time >= minite_to_save_video or  video_file_name == 0 :
        ## where H = heigth, W = width, C = channel 
        H, W, C = frame.shape
        
        print('time.time()-->',time.time(),'video_file_name-->', video_file_name,  ' #####')
        start_time = time.time()

        video_file_name = str(time.mktime(datetime.datetime.now().timetuple())).replace('.0', '')
        output_save_directory = output_stream+str(int(video_file_name))+'.mp4'


        fourcc = cv2.VideoWriter_fourcc(*'avc1')
        
        writer = cv2.VideoWriter(output_save_directory, fourcc,20.0,(W, H), True)

    # check to see if we should write the frame to disk
    if writer is not None:
        
        try:
            writer.write(frame)

        except Exception as e:
            print('Error in writing video output---> ', e)


  


• Piwik 3 Development Update #4 – Important notes and breaking changes

  2 octobre 2016, par Piwik Core Team — Community, Development

  As mentioned in the previous development updates #1 New UI design, API changes & release date, #2 Git master branch will become Piwik 3 and #3 Marketplace we are actively working on the Piwik 3 update and we will release a first beta of it soon. While the update brings many new features and bugfixes, it also comes with some important changes that may require your attention which we detail in this blog post.

  Database updates

  To keep Piwik upgrades as easy as possible, we have usually avoided database schema changes that affect large tables during the Piwik 2.X release cycle. The Piwik 3 update will however require several database updates in order to fix some limitations and bugs in the Piwik database schema. If you have a fair amount of traffic and/or large Piwik database, we recommend to execute the database updates for Piwik 3 on the command line.

  If you struggle updating Piwik you can also get in touch with the Piwik Support and ask for a quote so we can help you with upgrading.

  New server & browser Requirements

  Piwik 3 updates the server requirements. Piwik 3 now requires :

  • PHP 5.5.9 or newer (we used to require PHP 5.3+),
  • MySQL 5.5 or newer or MariaDB (we used to require MySQL 4.1+).

  If you are still on an old PHP and MySQL version we highly recommend to update directly to PHP 7 and a recent MySQL version (MySQL 5.7+).

  Piwik 3 also drops support for the older browsers IE8 and IE9.

  Default filter_limit now applies to all HTTP API methods (#8458)

  In the past the default filter_limit of 100 rows was applied to HTTP API methods that return a report. This means that by default :

  • when you requested a method like SitesManager.getAllSites, UsersManager.getUsers or Goals.getGoals (which are not reports), we returned all rows.
  • when you fetched a report like Actions.getPageUrls (which is a report), the result was limited to 100 rows.

  This behaviour was inconsistent and it was hard to understand which methods apply the default limit and which did not. We now apply the default limit to all HTTP API methods by default.

  If your API consumer or app needs to fetch all results for an API method, you can append the following parameter to the URL : &filter_limit=-1. Alternatively, if you wish to change the default filter_limit automatically for all APIs, you can override the API_datatable_default_limit config setting in your config/config.ini.php file.

  For more information about the various APIs parameters you can use, see Piwik Analytics HTTP API Reference.

  Proxy client IP detection (#10342)

  This is only important if you are using the proxy_client_headers[] config in the config/config.ini.php file, ie. your Piwik server is behind a proxy.

  When Piwik is set up to fetch the client IP address from the proxy headers, and the header contained more than one IP address, we used to use the last IP address. From Piwik 3 we will be using the first IP address which is in line with the protocol definition. For example if HTTP_X_FORWARDED_FOR contains multiple IP addresses, we now use the first IP instead of the last one.

  Writable Piwik JavaScript Tracker file piwik.js

  From Piwik 3 we recommend to have the file /piwik.js writable in your Piwik directory, so that the PHP and webserver processes can edit this file. It is not required to have the file writable for Piwik to function well, but we are working on some enhanced features that will only work when the file is writable. If you don’t know whether this file is writable, go to “Administration => System Check” as a Super User and Piwik will display a warning if the file is not writable. If needed, you might be able to make the file writable by executing a command like chmod 0755 piwik.js or chown $webuser piwik.js (on Linux).

  Changes for plugin developers

  In the previous development updates we have already introduced some of the changes that affect Piwik plugin developers. We have made several improvements to the Marketplace that allow developers to promote their plugin better and to maintain their plugin page easier. We have also created a migration guide for plugin developers to make it easier to migrate a plugin to Piwik 3.

  For a list of all changes have a look at the developer changelog.

  Until our next Piwik 3 update, be well, and Happy Analytics !

• Non-RSA TLS1.2 Packet decryption

  7 février 2017, par Joseph Wahba

  I am trying to decrypt a pcap file. This pcap file contains a capture of an HLS encrypted video stream. The pcap contains TLSv1.2 packets.

  Below are some information from the pcap file

  Server Hello message Cipher Suite :

  TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384.

  EC Diffie-Hellman server Params : pubkey (1)

  The Certificate Status message :

  Signature Hash Algorithm Hash : SHA256

  Signature Hash Algorithm Signature : ECDSA

  Client Key Exchange Message

  EC Diffie-Hellman server Params : pubkey (2)

  I tried to follow this Wireshark SSL decryption tutorial. But it seems that it works only for RSA encryptions.
  I have been researching for a while and found this discussion. I am quoting an extract from this discussion :

  There is an important parameter to mind : decryption of a passively
  recorded session (with a copy of the server private key) works only if
  the key exchange was of type RSA or static DH ; with "DHE" and "ECDHE"
  cipher suites, you won’t be able to decrypt such a session, even with
  knowledge of the server private key. In that case, you will need
  either the negotiated "master secret", or to use the server private
  key to actively intercept the connection

  It’s note worthy that I have the client private key. In my case, the client is FFmpeg video streamer (FFplay). I had a look also on the TLS v1.2 RFC.

  My question :

  Is it possible to do a decryption in this scenario ? If yes, what do I need to have to do so ?

  Is the decryption done using the client’s private key or using the pre_shared_master (i.e. Diffie-Hellman) ?