Recherche avancée

Sur d’autres sites (10913)

• Create a rolling X second webcam buffer in Linux, press button saves to file

  13 août 2016, par Grant Gibson

  I’m working on a webcam installation with an ’instant replay’ feature. The concept is basically this :

  1. Webcam captures live, 24/7
  2. When user presses a key, the last (previous) 30 seconds of video saves to a file
  3. I’ll then compress that video using something like FFMPEG and upload to a remote server

  I’m fine with step 3 and beyond, but I haven’t been able to find a solution that does the equivalent of a FIFO buffer for video streams [i.e. pretty much what the ’rewind live tv’ buffer on TiVo does].

  Does anyone know of a way to keep a rolling webcam video/audio buffer that can be exported to a file ?

  Design considerations :

  • I’m planning to use a standard webcam, but open to other suggestions
  • Recording would ideally be 1080p, 30fps
  • Recording must include sound
  • Linux hardware and OS can be specified in the answer, there are no existing pre-requisites. Raspberry Pi would be nice if that’s possible, but equally fine with a small Intel machine (e.g. NUC).
  • There’s no requirement to save the 24/7 stream, but it’s ok if that’s a by-product. So, storage permitting it can be saving to a file continuously for say 12 hours and just ’cat’ the last 30 secs to a separate file, if that’s an option ? But better would be the 30 sec rolling FIFO buffer that could potentially do the whole job in RAM.
  • The ’save instant replay’ button will eventually be a physical pushbutton rather than a keyboard key. However, I’ve got that side of things covered (if the solution is RPi I’d use the GPIO pins, if it’s an Intel box I’d probably use an Arduino in HID mode to simulate a keyboard press).

• Piwik SSO options and why is it useful ?

  8 novembre 2017, par Piwik Core Team — Plugins

  Bored with typing again and again different logins and passwords for each service you have access to ? Would you like to add hundreds or thousands of users with different roles to your Piwik at once ? Would you like to save time and effort of managing your users while increasing the security in your business ? Guess what, Piwik has come up with great features to do just that.

  But what is a SSO ?

  Before introducing you to new Piwik features, let me explain what a SSO is.
  SSO is the acronym for Single Sign On. As its name suggests this authentication process allows a user to access multiple applications with one set of login credentials.

  Advantages of using a SSO are numerous :

  • improving security, for example when an employee is leaving your company, how can you check that all his credentials have been removed ?
  • reducing employees time-wasters such as having to enter logins/passwords each time.
  • providing a centralized database for administrators. They can then easily manage permissions of all employees saving them heaps of time.
  • reduces support costs related to authentication / accounts management.

  In order to provide SSO options, two Piwik plugins have been developed and are available on the marketplace :

  • SAML
  • LDAP

  SAML

  

  SAML stands for “Security Assertion Markup Language”, it is a standard in order to exchange authentication and authorization between an identity provider (OneLogin, Okta, Ping Identity, ADFS, Google, Salesforce, SharePoint…) and a service provider.
  An identity provider is an online service that authenticates users on the Internet by using security tokens.

  Are you wondering if your business or organization is using any of these providers ? We recommend to ask your operations team or sysadmin.

  At InnoCraft, we developed a plugin in order to allow SSO with SAML for Piwik. It can ensure consistent access control across the enterprise and external providers, potentially reducing support costs related to authentication and accounts management.

  The installation process is straightforward. All you need is to get the SAML premium feature from the marketplace. Once installed, you will access the SAML configuration interface through the admin where you can configure various settings :

  • SAML Status
  • Identity Provider (Entity ID, SSO endpoint info, Public x509 certificate)
  • Just-in-time provisioning and Mapping attributes
  • Access Synchronization
  • Advanced settings

  

  From there you will need to follow our detailed documentation to have it up and running :
  https://piwik.org/docs/login-saml/.
  Once finished, you will then be able to use SAML to authenticate to your Piwik account :

  

  As all premium features, SAML is eligible to a 30-day period money back guarantee, so do not hesitate to have it a try.

  LDAP

  

  LDAP stands for Lightweight Directory Access Protocol. As its names implies LDAP is a directory, hosted on a server, which organizes the data about people in your company.
  Thanks to the LDAP plugin, Piwik can be connected to your LDAP infrastructure and then use all its power in order to give each individual an access with different rights according to their needs.

  Let’s say that you have 1,000 employees within a company and they all need right now an access to the analytics reports in Piwik with different roles. This is what LDAP can do.

  Moreover if your business or organization is already using LDAP, we recommend using the LDAP connector for Piwik for better security, to stop wasting time of your users and sysadmins, and to reduce the costs related to account management.

  You understood it well. LDAP is a plugin which saves a LOT of time within an organization. Here is a preview of the settings part :

  

  LDAP has been developed by the Piwik core team and is available as a Free plugin on the marketplace.

  Try it now within the marketplace

  If you are surprised by the possibilities that Piwik is offering in terms of plugins, the good news is that many other plugins are waiting for you on the marketplace. Check out our premium marketplace which offers state-of-the-art plugins to get the most out of Piwik.

  And if you are a developer feel free to create your own plugin, a detailed documentation is available at : https://developer.piwik.org/guides/getting-started-part-1.

• Building ffmpeg libraries for third party usage

  23 mars 2023, par mikeProgrammer

  I am trying to create bindings for FFmpeg in Elixir programming language and would love to handle FFmpeg binaries for users of my library.

  


  The whole flow is as follows :

  


  

  1. Write some function definition in Elixir

  


  2. Implement it in in C using ffmpeg libs

  


  3. Compile C code as shared library

  


  4. When running application, Erlang Virtual Machine will load my dynamic library

  


  


  The question is how to compile and include ffmpeg libs in my shared lib so that users of my Elixir lib don't have to install any native dependencies.

  


  Here is what I was trying :

  


  


  1. Compile ffmpeg libs as shared ones. When my Elixir lib is compiling, it downloads precompiled ffmpeg archive, extracts its content and links to it when compiling native functions. I realized that this still won't work as ffmpeg shared libs depend on other shared libs that user has to install on their own.

     


  


  2. Compile ffmpeg libs as static ones and include them in my native shared library using —whole-archive linker option. Here I am getting

     


  


  


  /usr/bin/ld : ffmpeg_build/lib/libavcodec.a(vp9lpf_16bpp.o) : warning : relocation against ff_pw_1' in read-only section .text'
/usr/bin/ld : ffmpeg_build/lib/libavcodec.a(cavsdsp.o) : relocation R_X86_64_PC32 against symbol `ff_pw_5' can not be used when making a shared object ; recompile with -fPIC
/usr/bin/ld : final link failed : bad value
collect2 : error : ld returned 1 exit status

  


  The command I am using

  


  cc -fPIC -I/home/michal/.asdf/installs/erlang/25.1/erts-13.1/include -Iffmpeg_build/include -Ic_src/xav -shared -DXAV_DEBUG=1 c_src/xav/xav_nif.c c_src/xav/reader.c c_src/xav/utils.c -o /home/michal/Repos/xav/_build/test/lib/xav/priv/libxav.so -Lffmpeg_build/lib -Wl,--whole-archive -lavcodec -lswscale -lavutil -lavformat -Wl,--no-whole-archive


  


  FFmpeg configuration

  


  ./configure \
--prefix="$PWD/ffmpeg_build" \
--extra-cflags="-fPIC -I$PWD/ffmpeg_build/include" \
--extra-ldflags="-L$PWD/ffmpeg_build/lib" \
--enable-pic
--disable-programs


  


  Does anything that I am trying to do make sense to you ?

  


  When I am installing ffmpeg-libs package on Fedora, it depends on other shared libs that are automatically downlaoded but what I would love to achieve is to provide self-contained ffmpeg build that can be used in other shared libraries.