Forensic Authentication of Digital Audio and Video Files

Requests of a forensic laboratory to conduct authenticity examinations of digital audio and video files are usually based on one or more of the following reasons: legal, investigative or administrative. This chapter discusses the types of common recording devices, digital file formats and evidence requirements. Next, it talks about the physical laboratory facility, and requisite software and equipment. The chapter explains the protocols for conducting scientific authenticity examinations of digital audio and video files, including critical listening and visual reviews, data analysis and temporal/frequency analyses. The protocol used when conducting forensic authenticity examinations of digital audio and video files is based on a number of different analysis steps, as applicable, which are generally categorized as follows: hashing and cloning; playback and conversion optimization; digital data analysis; audio analyses; video analyses; and preparation of work notes. The chapter also talks about the importance of expert testimony, and provides some case examples.