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• avconv "select" filter doesn't discard first frames

  1er avril 2014, par user2152106

  I'm trying to segment a video using avconv's "select" filter to extract only a specific range of frames from the input file. As an example, imagine I have a 60fps video file called input.mp4, with 3000 frames (i.e. 50 seconds), and I run

  avconv -i input.mp4 -vf "select='lt(n,2000)'" output1.mp4
  
  avconv -i input.mp4 -vf "select='gte(n,2000)'" output2.mp4

  What I expect is that output1.mp4 has the first 2000 frames of input.mp4 (and lasts 33 seconds), and output2.mp4 has the last 1000 (and lasts 17 seconds).

  I count the frames by running

  avconv -i video.mp4 -vcodec copy -an -f null /dev/null 2>&1 | grep 'frame='

  and checking the value assigned to 'frame'.

  What I actually get, is that output1.mp4 has 2000 frames and lasts 33 seconds, but output2.mp4 has 2999 frames, and still lasts the full 50 seconds. When I open output2.mp4, I notice that the first 2000 frames of the video are actually just a repetition of the 2000th frame of the input, i.e. the first 2000 frames seem to be correctly filtered, but replaced by the first of the accepted frames.

  This is not a pts problem. I check the number of packets and their relative pts using avprobe :

  avprobe -show_packets output2.mp4
  
  echo $(avprobe -show_packets output2.mp4 2>/dev/null | grep PACKET | wc -l)/2 | bc

  I see that there are actually 2999 packets.

  What am I doing wrong ?

  Side questions :

  • Assuming I'm doing something wrong, why does output2.mp4 contain 2999 rather than the full 3000 ?
  • The behaviour doesn't change whether I use the "gte" or "gt" function in the filter. Why could that be ?

• MKV Video Faster Plays Faster

  4 avril 2014, par Ankush

  I have C# program which screenshots 3 times per second & adds this to mkv ( VP8 ) video, set FPS to 3,encoded video works but plays faster, the total length of video player shows is wrong & while playing it doesn't plays smooth it jumps like from 1sec -> 3sec -> 5sec means instread of 1 -> 2 ->3..

  There is something wrong with pts value,

  if ( codecContext->coded_frame->pts != AV_NOPTS_VALUE )
  
  {
  
   packet.pts = av_rescale_q( packet.pts, codecContext->time_base, pVideoStream->time_base );
  
  }
  
  
  
  if ( codecContext->coded_frame->pkt_dts != AV_NOPTS_VALUE )
  
  {
  
   packet.dts = av_rescale_q( packet.dts, codecContext->time_base, pVideoStream->time_base );
  
  }

  while debugging codecContext->time_base shows 3FPS ( num=1 den=3 ) & pVideoStream->time_base shows ( num=1 den=1000) & packet.pts & packet.dts shows 0 ( everytime )

  Whats wrong ? Anyone please give me some hint atleast.

• Your introduction to personally identifiable information : What is PII ?

  15 janvier 2020, par Joselyn Khor — Analytics Tips, Privacy, Security
  When it comes to personally identifiable information (PII), people are becoming more concerned with data privacy. Identifiable information can be used for illegal purposes like identity theft and fraud. 

  So how can you protect yourself as an innocent web browser ?

  If you’re a website owner – how do you protect users and your company from falling prey to privacy breaches ?

  As one of the most trusted analytics companies, we feel our readers would benefit from being as informed as possible about data privacy issues and PII. Learn how you can keep yours or others’ information safe.

  

  Table of Contents

  What does PII stand for ?

  PII acronym

  PII is an acronym for personally identifiable information.

  PII definition

  Personally identifiable information (PII) is a term mainly used in the United States.

  The appendix of OMB M-10-23 (Guidance for Agency Use of Third-Party Website and Applications) gives this definition for PII :

  “The term ‘personally identifiable information’ refers to information which can be used to distinguish or trace an individual’s identity, such as their name, social security number, biometric records, etc. alone, or when combined with other personal or identifying information which is linked or linkable to a specific individual, such as date and place of birth, mother’s maiden name, etc.”

  What can be considered personally identifiable information (PII) ? Some PII examples :

  • Full name/usernames
  • Home address/mailing address
  • Email address
  • Credit card numbers
  • Date of birth
  • Phone numbers
  • Login details

  • Precise locations
  • Account numbers
  • Passwords
  • Security codes (including biometric records)
  • Personal identification numbers
  • Driver license number
  • Get a more comprehensive list here

  What’s non-PII ?

  Anonymous information, or information that can’t be traced back to an individual, can be considered non-PII. 

  Who is affected by the exploitation of PII ?

  Anyone can be affected by the misuse of personal data. Websites can compromise your privacy by mishandling or illegally selling/sharing your data. That may lead identity theft, account fraud and account takeovers. The fear is falling victim to such fraudulent activity. 

  PII can also be an issue when employees have access to the database and the data is not encrypted. For example, anyone working in a bank can access your accounts ; and anyone working at Facebook can read your messages. This shows how privacy breaches can easily happen when employees have access to PII.

  Website owner’s responsibility for data privacy (PII and analytics)

  If you’re using a web analytics tool like Google Analytics or Matomo, best practise is to not collect PII if possible. This is to better respect your website visitor’s privacy. 

  If you work in an industry which needs people to share personal information (e.g. healthcare, security industries, public sector), then you must collect and handle this data securely. 

  

  The US National Institute of Standards and Technology states : “The likelihood of harm caused by a breach involving PII is greatly reduced if an organisation minimises the amount of PII it uses, collects, and stores. For example, an organisation should only request PII in a new form if the PII is absolutely necessary.” 

  How you’re held accountable remains up to the privacy laws of the country you’re doing business in. Make sure you are fully aware of the privacy and data protection laws that relate specifically to you. 

  To reduce the risk of privacy breaches, try collecting as little PII as you can ; purging it as soon as you can ; and making sure your IT security is updated and protected against security threats. 

  With data collection tools like web analytics, data may be tracked through features like User ID, custom variables, and custom dimensions. Sometimes they are also harder to identify when they are present, for example, in page URLs, page titles, or referrers URLs. So make sure you’re optimising your web analytics tools’ settings to ensure you’re asking your users for consent and respecting users’ privacy.

  If you’re using a GDPR compliant tool like Matomo, learn how you can stop processing such personal data

  PII, GDPR and businesses in the US/EU

  You may get confused when considering PII and GDPR (which applies in the EU). The General Data Protection Regulation (GDPR) gives people in the EU more rights over “personal data” – which covers more identifiers than PII (more on PII vs personal data below). GDPR restricts the collection and processing of personal data so businesses need to handle this personal data carefully. 

  According to the GDPR, you can be fined up to 4% of their yearly revenue for data/privacy breaches or non-compliance. 

  

  In the US, there isn’t one overarching data protection law, but there are hundreds of laws on both the federal and state levels to protect PII of US residents. US Congress has enacted industry-specific statutes related to data privacy like HIPAA. Recently state of California also passed the California Consumer Privacy Act (CCPA). 

  To be on the safe side, if you’re using analytics, follow matters relating to “personal data” in the GDPR. It covers more when it comes to protecting user privacy. GDPR rules still apply whenever an EU citizen visits any non EU site (that processes personal data).

  Personally identifiable information (PII) vs personal data

  PII and “personal data” aren’t used interchangeably. All personal data can be PII, but not all PII can be defined as personal data.

  The definition of “personal data” according to the GDPR :

  

  This means “personal data” covers more identifiers, including online identifiers. Examples include : IP addresses and URL names. As well as seemingly “innocent” data like height, job position, company etc. 

  What’s seen as personal data depends on the context. If a piece of information can be combined with others to establish someone’s identity then that can be considered personal data. 

  Under GDPR, when processing personal data, you need explicit consent. So best to be compliant according to GDPR definitions of “personal data” not just what’s considered “PII”.

  How do you keep PII safe ?

  • Try not to give your data away so easily. Read through terms and conditions.
  • Don’t just click ‘agree’ when faced with consent screens, as consent screens are majorly flawed. 
  • Disable third party cookies by default. 
  • Use strong passwords.
  • Be wary of public wifi – hackers can easily access your PII or sensitive data. Use a VPN (virtual private network)
  • Read more on how to keep PII safe. For businesses here’s a checklist on PII compliance.

  How Matomo deals with PII and personal data

  Although Matomo Analytics is a web analytics tool that tracks user activity on your website, we take privacy and PII very seriously – on both our Cloud and On-Premise offerings. 

  If you’re using Matomo and would like to know how you can be fully GDPR compliant and protect user privacy, read more :
  

  • Learn how to not process any personally identifiable information – Anonymise IP addresses, user IDs, and order IDs
  • Matomo protects user privacy by talking the talk and walking the walk
  • Stay ahead of the GDPR with a privacy-respecting analytics platform
  • 11 ways Matomo helps you protect your visitor’s privacy

  Disclaimer

  We are not lawyers and don’t claim to be. The information provided here is to help give an introduction to issues you may encounter when dealing with PII. We encourage every business and website to take data privacy seriously and discuss these issues with your lawyer if you have any concerns. 

  Additional resources :

  • https://www.consumeraffairs.com/finance/identity-theft-statistics.html#identity-theft-trends-in-2019
  • https://ec.europa.eu/info/law/law-topic/data-protection_en
  • https://iclg.com/practice-areas/data-protection-laws-and-regulations/usa
  • https://www.csoonline.com/article/3215864/how-to-protect-personally-identifiable-information-pii-under-gdpr.html
  • https://ico.org.uk/for-organisations/guide-to-data-protection/guide-to-the-general-data-protection-regulation-gdpr/key-definitions/what-is-personal-data/