Acquiring Raw Video and Metadata

Metadata

Any information about a video: from technical information embedded in the file that allows the video to function, such as format and duration, to descriptive information about the content to help you understand or find it–such as keywords, security restrictions, geographic locations, and so on. Metadata is critical to any future use, and is important throughout the archiving process.

Despite what is sometimes said, images almost never speak for themselves. They require context and description to make sense, to corroborate their factuality, and to be accessible beyond one person’s memory or desktop.

Metadata can be automatically generated and embedded in the file, such as with technical metadata, or it can be manually recorded on an external medium, such as with descriptions, security flags, and keywords in a database. Metadata capture sometimes needs to be manually enabled on your device, such as with GPS or location services.

Completeness

The quality of having all of the information a record contained when it was created, and that its original context is maintained. Incomplete records are not as reliable as complete ones, since one might not know what information is missing and why. Transcoding a video to another format can reduce the image quality and discard metadata, making the video less complete and therefore less reliable. Keeping original video files, documenting context, and organizing videos in a way that maintains the original order of video files contributes to the completeness of the video records.

Authenticity

The quality of being genuine, not fake or counterfeit, and free from tampering. Authenticity means that an object was actually created by the person represented as its creator, and that it was actually created at the time and place that is represented as its time and place of creation. Video footage that has been manipulated or altered but is represented as if it had not been, for example, is not authentic.

To authenticate a video means to verify the relationship between it and its creator and point of creation. Documentation about who created something, when and where it was created, and the chain of custody can provide a starting point for this authentication process.

Original Files

In the digital realm, the “original file” is any copy of a file that is exactly the same (i.e. bit-for-bit) as the file in question when it was created. This means that there are no accidental or deliberate alterations to any aspect of the file, including its format and technical specifications.

Malware

A term derived from “malicious software,” and that refers to all computer viruses, worms, Trojans, and spyware.

Selection

The process of identifying materials to be acquired, or to be preserved, because of their enduring value. Having selection criteria, or a selection policy, helps ensure you acquire and save only what is most important.

Chain of Custody

Chronological documentation that shows who has held or controlled a video file from the moment it was created. The ability to show an unbroken chain of custody is one important indicator of the authenticity of a video, and therefore a factor in using video as evidence.

Download

To receive data from a remote computer system and save it in a local computer system. The inverse of download is “upload.”

Master

The earliest generation or highest-quality output of a video from which duplicates are made.

Original Order

The archival principle of maintaining files in the same order they were created. Original order is important to preserve context and the relationship between individual files, so that you can make sense of each file and of the whole. Keeping files in their original context makes them more complete and reliable.

Integrity

The quality of being whole, unaltered, and uncorrupted. A file that is not intact may not be usable or may have decreased informational and evidential value. Videos files can lose their integrity if they are accidentally mishandled, deliberately tampered with, or if data corruption occurs in transfer or storage due to hardware or software malfunction. The best way to ensure integrity is to establish a system to check file fixity regularly (e.g. by computing hashes and checking them against a registry of previously computed hashes) and to restore any corrupted files from an intact copy.

Copyright

A legal protection intended to give the creator of original work exclusive rights to their work for a designated length of time. It gives the creator the exclusive right to copy, use, adapt, show, and distribute their own work, and the right to determine who else can copy, use, adapt, show, and distribute the work.

Transcode

To re-encode a digital file to a different encoding scheme, such as converting an H.264/MPEG-4 AVC video to Apple ProRes. Transcoding is usually done when a video’s encoding is not supported by the system that needs to use it. Transcoding fundamentally alters the file, although lossless methods can allow the original data to be reconstructed from the transcoded data.

Derivative

A copy of a video generated from a master that is usually in a different format and of lower quality than the master. Derivatives can be made for various uses, such as web upload or DVD.

File Format

The specification by which a digital file is encoded. Some file formats are designed to store particular kinds of data while others are more like containers that can hold many kinds of data. Common video file formats like Quicktime (.mov), AVI, and mp4 are container formats that contain video and audio streams, metadata, subtitle tracks, etc.

Command-Line Interface

A way of interacting with a computer program which involves typing lines of text in a command-line shell. Some programs are only available with command-line interfaces, which facilitate their automation and use in programming scripts. However, command-line interfaces can be harder for casual computer users to interact with than graphical user interfaces (GUI), which use windows, icons, menus, and pointers.

Embedded Metadata

Metadata that is stored within the digital object it describes. Some embedded metadata, such as file size, are essential to the functioning of the file, and are always written to the file by the device or software system. Other embedded metadata are non-essential and can be optionally added (e.g. rights information). Embedded metadata is not guaranteed to be accurate—for example, if your camera is set to the wrong date. Embedded metadata stay with the digital object as long as the object is intact, but can be intentionally stripped or altered. Embedded metadata can be lost if a file is transcoded to another format.

Graphical User Interface

A way of interacting with a computer program that involves using windows, icons, menus, and pointers. Most computer users are familiar with graphical user interfaces. GUIs can be easier for casual users to interact with than command-line interfaces (CLI), which require commands to be typed as lines of text.

Hash Function

An algorithm that computes a hash value or checksum from any set of data, like a file. Common hash functions include MD5 and SHA1. Hash functions are used to check file integrity and for security purposes.

Cataloging

Creating and organizing descriptive information in a structured way so that resources can be found, used, and understood. Cataloging expands on basic metadata, and enables users to access content in multiple ways.

Media Management

The process of keeping track of media, such as the video files in your collection, and overseeing any actions performed on your media, such as backup, refreshment or migration. Media management can be performed manually, or with the aid of a software system (e.g. a media asset management (MAM) system).