Recherche avancée

Sur d’autres sites (4616)

• avformat/mux : Preserve sync even if later packet has negative ts

  18 janvier 2022, par Andreas Rheinhardt

  avformat/mux : Preserve sync even if later packet has negative ts
  write_packet() has code to shift the packets timestamps
  
  to make them nonnegative or even make them start at ts zero ;
  
  this code inspects every packet that is written and if a packet
  
  with negative timestamp (whether this is dts or pts depends upon
  
  another flag ; basically : Matroska uses pts, everyone else dts)
  
  is encountered, this is offset to make the timestamp zero.
  
  All further packets will be offset accordingly (with the offset
  
  converted according to the streams' timebases).
  This is based around an assumption, namely that the timestamps
  
  are indeed non-decreasing, so that the first packet with negative
  
  timestamps is the first packet with timestamps. This assumption
  
  is often fulfilled given that the default interleavement function
  
  by default interleaves per dts ; yet there are scenarios in which
  
  it may not be fulfilled :
  
  a) av_write_frame() instead of av_interleaved_write_frame() is used.
  
  b) The audio_preload option is used.
  
  c) When the timestamps that are made nonnegative/zero are pts
  
  (i.e. with Matroska), because the packet with the smallest dts
  
  is not necessarily the packet with the smallest pts.
  
  d) Possibly with custom interleavement functions.
  
  In these cases the relative sync of the first few packet(s) is offset
  
  relative to the later packets. This contradicts the documentation
  
  ("When shifting is enabled, all output timestamps are shifted by
  
  the same amount").
  Therefore this commit changes this : As soon as the first packet
  
  with valid timestamps is output, it is checked and recorded whether
  
  the timestamps need to be shifted. Further packets are no longer
  
  checked for needing to be offset ; instead they are simply offset.
  
  In the cases above this leads to packets with negative timestamps
  
  (and the appropriate warnings) instead of desync. This will mostly
  
  be fixed in the next commit.
  This commit also factors handling the avoid_negative_ts stuff out
  
  of write_packet() in order to be able to return immediately.
  Tickets #4536 and #5784 as well as the matroska-avoid-negative-ts-test
  
  are examples of c) ; as has been said, some timestamps are now negative,
  
  yet the ref file update does not show it because ffmpeg.c sanitizes
  
  the timestamps (-copyts disables it ; ffprobe and mkvinfo also show
  
  the original timestamps).
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavformat/internal.h
  • [DH] libavformat/mux.c
  • [DH] libavformat/options.c
  • [DH] tests/fate/matroska.mak
  • [DH] tests/ref/fate/matroska-avoid-negative-ts

• CJEU rules US cloud servers don’t comply with GDPR and what this means for web analytics

  17 juillet 2020, par Jake Thornton
  Breaking news : On July 16, 2020, the Court of Justice of the European Union (CJEU) has ruled that any cloud services hosted in the US are incapable of complying with the GDPR and EU privacy laws.

  In August 2016, the EU-US Privacy Shield framework came into effect, which “protects the fundamental rights of anyone in the EU whose personal data is transferred to the United States for commercial purposes. It allows the free transfer of data to companies that are certified in the US under the Privacy Shield.” – European Commission website

  However after today’s CJEU ruling, this Privacy Shield framework became invalidated due to significant differences between EU and US privacy laws.

  European privacy law activist Max Schrems summarises with “The Court clarified for a second time now that there is a clash between EU privacy law and US surveillance law. As the EU will not change its fundamental rights to please the NSA, the only way to overcome this clash is for the US to introduce solid privacy rights for all people – including foreigners. Surveillance reform thereby becomes crucial for the business interests of Silicon Valley.” – noyb website

  Today’s ruling also continues to spark concern into the legitimacy of US privacy laws which doesn’t fully protect people’s personal data when hosted on cloud servers based in the US.

  

  How will this affect you ?

  For any business operating a website in the EU or if you have traffic coming to your website from EU visitors, you need to know what data you’re capturing and where this data is being stored.

  Here’s what Maja Smoltczyk (Berlin’s Commissioner for Data Protection and Freedom of Information) says :

  Controllers who transfer personal data to the USA, especially when using cloud-based services, are now required to switch immediately to service providers based in the European Union or a country that can
  ensure an adequate level of data protection. The CJEU has made it refreshingly clear that data exports are not just financial decisions, as people’s fundamental rights must also be considered as a matter of priority. This ruling will put
  an end to the transfer of personal data to the USA for the sake of convenience or to cut costs.

  The controller is you (not Google) and by transferring data to the US you are at risk of being fined up to €20 million or 4% of your annual worldwide turnover for not being GDPR compliant. 

  It’s you who has to take action, not Google or other US companies. The court’s decision has immediate effect. While we assume there will be a grace period, companies should act now as finding and implementing alternatives solution can take a while. 

  Can no data be exported outside the EU anymore ?

  Data can still be exported outside the EU if an adequate level of data protection is guaranteed. This is the case for some trading partners of the EU such as New Zealand, Japan, Switzerland, and Canada. They have been certified by the EU as having a comparable level of privacy protection and therefore demonstrate adequacy at a country level.

  Necessary data can still flow to countries like the US too. This is for example the case when someone books a hotel in the US or when sending an email to someone in the US. Backups for disaster recovery and most other reasons don’t qualify as necessary.

  In all other cases you can still send data to countries like the US if you get explicit and informed consent from a user. Meaning the user has been informed about all possible risks of sending the data to the US and who can access the data (for example the US government).

  How this affects Google Analytics and Google Tag Manager users

  If your website is using Google Analytics, the safest bet is to deactivate it immediately. Otherwise, you must ask for consent from everyone who visits your website and inform them that the data will be processed in the United States under less strict privacy laws and all associated risks. If you don’t, you could be liable to privacy law infringements and face being fined for not complying with the GDPR. This also applies to Google Tag Manager as it transfers the IP address to the US which is considered personal data under the GDPR.

  Consent needs to be :

  • Freely given (the user must have a choice to not give consent and be able to opt out at any time) 
  • Informed (you need to disclose who is processing the data, what data is processed, where the data will be stored and how to opt out) 
  • Specific (consent is only valid for the specific informed purpose) 
  • Unambiguous (for example pre-ticked boxes or similar aren’t allowed)

  

  If users don’t give you consent, you are not allowed to track them using Google Analytics or any other US based cloud solution.

  Update August 19, 2020

  A month after this ruling, over 100 complaints have been filed against websites for continuing to send data to the US via Google Analytics or Facebook, by the European privacy campaign group noyb. It’s clear Google and Facebook fall under US surveillance laws such as FISA 702 and the court clearly ruled these companies cannot rely on SCCs to transfer data to the US. Anyone still using Google Analytics is now at risk of facing fines and compensation damages. 

  How this affects Matomo users

  Our cloud servers are based in Germany.

  Matomo On-Premise users choose the location of their data themselves. If the servers are located in the EU nothing changes. If the servers are located outside the EU and the website targets EU users and tracks personal data, then you need to assess whether you are required to ask for tracking consent.

  If the data is stored inside the EU you can use Matomo without asking for any consent and you can continue tracking users even if they reject a consent screen which greatly increases the quality of your data.

  Want to avoid informing users about transferring their data to the US and all associated risks ?

  Try Matomo now for free ! No credit card required.

  Download Matomo

• ffmpeg capture output from child window

  3 janvier 2013, par glitchyme

  using xwininfo -all I'm able to see the stats of any window, along with its child windows

  xwininfo: Window id: 0x3c000ba "Electro - The Slag & Prototype Raptor - Crescendo - YouTube - Mozilla Firefox"
  
  
  
    Root window id: 0xa8 (the root window) (has no name)
  
    Parent window id: 0xc001b8 (has no name)
  
       2 children:
  
       0x3c00175 (has no name): ()  1388x876+0+0  +52+24
  
          5 children:
  
          0x3d210ab (has no name): ()  854x510+225+197  +277+221
  
             1 child:
  
             0x3d210ac (has no name): ()  854x510+0+0  +277+221
  
                1 child:
  
                0x40404de "plugin-container": ("plugin-container" "Plugin-container")  854x510+0+0  +277+221
  
                   2 children:
  
                   0x40404e1 (has no name): ()  854x510+0+0  +277+221
  
                   0x40404df (has no name): ()  1x1+-1+-1  +276+220
  
          0x3ddbcf2 (has no name): ()  640x390+225+162  +277+186
  
             1 child:
  
             0x3ddbcf3 (has no name): ()  640x390+0+0  +277+186
  
                1 child:
  
                0x403d545 "plugin-container": ("plugin-container" "Plugin-container")  640x390+0+0  +277+186
  
                   2 children:
  
                   0x403d548 (has no name): ()  640x390+0+0  +277+186
  
                   0x403d546 (has no name): ()  1x1+-1+-1  +276+185
  
          0x3dac7f9 (has no name): ()  640x390+225+162  +277+186
  
             1 child:
  
             0x3dac7fa (has no name): ()  640x390+0+0  +277+186
  
                1 child:
  
                0x4039d8b "plugin-container": ("plugin-container" "Plugin-container")  640x390+0+0  +277+186
  
                   2 children:
  
                   0x4039d8e (has no name): ()  640x390+0+0  +277+186
  
                   0x4039d8c (has no name): ()  1x1+-1+-1  +276+185
  
          0x3c3f939 (has no name): ()  640x390+225+197  +277+221
  
             1 child:
  
             0x3c3f93a (has no name): ()  640x390+0+0  +277+221
  
                1 child:
  
                0x4011918 "plugin-container": ("plugin-container" "Plugin-container")  640x390+0+0  +277+221
  
                   2 children:
  
                   0x401191b (has no name): ()  640x390+0+0  +277+221
  
                   0x4011919 (has no name): ()  1x1+-1+-1  +276+220
  
          0x3c0d1dc (has no name): ()  1x1+0+97  +52+121
  
             1 child:
  
             0x3c0d1dd (has no name): ()  1x1+0+0  +52+121
  
                1 child:
  
                0x4002c1e "plugin-container": ("plugin-container" "Plugin-container")  1x1+0+0  +52+121
  
                   2 children:
  
                   0x4002c40 (has no name): ()  1x1+0+0  +52+121
  
                   0x4002c1f (has no name): ()  1x1+-1+-1  +51+120
  
       0x3c000bb (has no name): ()  1x1+-1+-1  +51+23
  
  
  
    Absolute upper-left X:  52
  
    Absolute upper-left Y:  24
  
    Relative upper-left X:  0
  
    Relative upper-left Y:  0
  
    Width: 1388
  
    Height: 876
  
    Depth: 24
  
    Visual: 0x23
  
    Visual Class: TrueColor
  
    Border width: 0
  
    Class: InputOutput
  
    Colormap: 0x20 (installed)
  
    Bit Gravity State: NorthWestGravity
  
    Window Gravity State: NorthWestGravity
  
    Backing Store State: NotUseful
  
    Save Under State: no
  
    Map State: IsViewable
  
    Override Redirect State: no
  
    Corners:  +52+24  -0+24  -0-0  ç0
  
    -geometry 1388x876-0-0
  
  
  
    Bit gravity: NorthWestGravity
  
    Window gravity: NorthWestGravity
  
    Backing-store hint: NotUseful
  
    Backing-planes to be preserved: 0xffffffff
  
    Backing pixel: 0
  
    Save-unders: No
  
  
  
    Someone wants these events:
  
        KeyPress
  
        KeyRelease
  
        ButtonPress
  
        ButtonRelease
  
        EnterWindow
  
        LeaveWindow
  
        PointerMotion
  
        Exposure
  
        VisibilityChange
  
        StructureNotify
  
        FocusChange
  
        PropertyChange
  
    Do not propagate these events:
  
    Override redirection?: No
  
  
  
    Window manager hints:
  
        Client accepts input or input focus: Yes
  
        Initial state is Normal State
  
        Displayed on desktop 0
  
        Window type:
  
            Normal
  
        Window state:
  
            Maximized Vert
  
            Maximized Horz
  
        Process id: 4087 on host jb
  
        Frame extents: 0, 0, 0, 0
  
  
  
    Normal window size hints:
  
        Program supplied minimum size: 18 by 97
  
        Program supplied maximum size: 1073741824 by 1073741824
  
        Program supplied window gravity: NorthWestGravity
  
    No zoom window size hints defined
  
  
  
    No window shape defined
  
    No border shape defined

  However, if I try capturing from the screen given the size and offset of the child window, then I risk losing data when another window floats ontop of it, I switch to another tab while recording, I resize the child window, or move the child window. Instead, I'd like to use ffmpeg to capture from specifically that child window.

  Ideas ? Tips ? Maybe some other hacks to accomplish this ? Thanks :)