Managing Video for Evidence: How can you manage your media to ensure it remains reliable and its provenance protected?

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Managing Video for Evidence: How can you manage your media to ensure it remains reliable and its provenance protected?

Now that you have the evidence, how can you manage your media to ensure it remains reliable and its provenance protected? Consider these questions below when sharing your comments in this discussion topic:

  • What are the particular challenges of managing citizen video versus videos produced by traditional human rights organizations/institutions?
  • What approaches have been taken to collect and preserve citizen video?
  • What standards and methods are employed to document the origin of video footage and how it was passed from the filmer onto others (i.e. chain-of-custody or provenance)?

Share your thoughts, experiences, questions, challenges and ideas by replying to the comments below.

For help on how to participate in this conversation, please visit these online instructions.


Chain of Custody

Before any piece of potential evidence can be used in a court proceeding, it needs to be entered into evidence.  This is the process by which information is authenticated.  For some types of evidence, it will be necessary to prove a chain of custody. This often involves a court hearing testimony that lays the foundation for the evidence and proves that 

  • it is what it purports to be and
  • it has not been tampered with or changed since it was created or found. 

Establishing the chain of custody often requires three types of testimony:

  1. that a piece of evidence is what it purports to be;
  2. that the evidence was in the continuous possession of individuals from the time it was created or seized until the time it is presented in court; and
  3. that the particular piece of evidence remained in substantially the same condition from the moment one person took possession of it until the moment it was transferred to someone else or introduced into court.

In other words, foundation testimony will prove that the particular exhibit sought to be introduced is in substantially the same condition as it was at the time the evidence was seized, and that the exhibit has remained in that condition through an unbroken chain of custody. 

Video evidence is easily transfered from one person to another. And, it can be easily altered by using programs such as photoshop etc. to enhance the quality, crop images, zoom in on something, or highlight certain elements. Often digital footage will be used for advocacy or other purposes. This may involve changing the footage to make it more effective for this purpose.  

From the perspective of a court, however, any manipulation of digital evidence will call its authenticity and reliability into question. It is possible to analyze such evidence to determine whether it has been tampered with or changed in any way. So, it is important to keep an original copy of any digital evidence somewhere safe. Work off copies if it is necessary to manipulate the footage for some other purpose.    

Summary of our archive processes

Questions of authenticity and provenance are important for us at the WITNESS Media Archive, and in all archives in general. Although most of the video in the WITNESS Media Archive comes directly from known sources, like WITNESS staff or partners, and has not been put to use in a legal evidence context, I thought I’d share some of our practices here.

In cases where we work with content producers before they film, we have provided printable templates to encourage them to document and log their footage. This ensures that key metadata, like who shot the video, is recorded and can be delivered to the archive along with the media. When video comes back with a staff person, I also review the footage with them and collect any additional relevant documentation before the transfer of custody into the archive.

When transferring video files to our archival storage (and between archival storage), we employ a file transfer tool called rsync that is more reliable than a simply drag and drop copying. This helps ensure that files are fully transferred without error, especially when we are copying a large amount of files over a slow network. 

We do not employ a forensic disk imaging method, as the hard drives that we use for transferring videos are not the objects we are trying to preserve (i.e. we don’t care if we are altering the hard drive in the process of transferring data off of them). If this is a concern, however, you should create forensic disk images rather than transferring individual files off your drives. Here is a page with more information on that workflow:

Our archival ingest process involves assigning identifiers and storage location to each new video object, extracting and populating our database with embedded technical metadata, running an MD5 hash on each video file, and creating a low-resolution watermarked proxy for access. We do not alter the original files. These ingest tasks are accomplished using scripts that rely on free or open source tools like MediaInfo and ffmpeg. This process ensures that objects are tracked from the time they enter the archive.

Once ingested, each video object is cataloged in our database. Videos are described according to WITNESS cataloging rules, which draw from the PBCore metadata standard. PBCore is a descriptive standard developed by the U.S. public broadcasting community for tracking audiovisual (production) assets. Preservation actions, such as fixity checks, are also recorded in the database according PREMIS, an international standard for preservation metadata. Description helps to make our video objects easy to find and retrieve.

We store our archived objects on dedicated RAID’ed servers. Access is limited to a few archive staff. We provide access to other staff by making copies to separate non-archive locations. We are currently backing up our collection in-house to LTO6 tape, and also sending copies of all our videos to a dark archive at the University of Texas Libraries for long-term preservation. This is a process that is still underway, and will help ensure the permanence of our collection.

To maintain authenticity and provenance when transferring objects from our archive to the University of Texas Libraries, we use a file packaging format standard developed by the Library of Congress called BagIt. BagIt allows us to package files along with metadata that allow the package to be validated and verified upon receipt. 

I’m writing this at the end of the day, so I apologize for the stream-of-consciousness style! I’d be interested in hearing about what others are doing, and happy to elaborate on anything I’ve mentioned if it’s helpful. 

An interesting example of manipulating video

Again, I am presenting some experiences from the International Criminal Tribunal for the former Yugoslavia (ICTY). This one concerns a Serbian journalist (Zoran Petrovic Pirocanac) that was effectively embedded with the Bosnian Serb Army in July 1995 in eastern Bosnia. He recorded some incriminating footage, showed it in a TV show and later went back and taped over the relevant parts with other footage (because he realised it was incriminating and could be dangerous for him). This is all related to Srebrenica cases.
 Here is a link to one article about this video:
 One of the erased parts contained images of bodies (piles of bodies) in front of the Kravica warehouse on July 13th 1995.
 This is a report on one of his testimonies:

This also concerns that case:

You can easily search for transcripts of this journalist testifying and maybe some of the issues raised by the Prosecutor, Defense and Judges might shed some light on this topic.

Resource for managing citizen video

We developed a resource for groups or individuals who are creating and collecting citizen video, but who needed more information on how to manage and preserve it so that it remains authentic and intact for future use.

It's called the Activists' Guide to Archiving Video, and it's available here (in English, Spanish, and Arabic):