Multimedia Forensics
Multimedia forensics refers collectively to those fields of forensic science that are concerned with audio, photographic, videographic, illustrated, animated and interactive forms of, and sources of, evidence. We’re able to process, preserve, examine, analyze and interpret a variety of multimedia file formats from almost any conceivable device or medium. More importantly, we’re able to do so in a forensically sound manner. This means that our opinions and conclusions regarding the content, author or subjects of interest will be replicable, credible and evidence-based. Our multimedia forensic capabilities are divided into three areas: audio forensics, video forensics and image forensics.
Video Forensics
Video forensics entails the processing and scientific examination, analysis, comparison and evaluation of video for investigative purposes. It also involves the detection of video editing and tampering, the extraction of audio, the production of still images from video, clarification and enhancement of footage, and the identification of or comparison between items or people of interest captured on video.
Common Video Forensic Tasks
Intertel’s video forensic capabilities have been requested by law enforcement, prosecutors, defence attorneys, corporations and private individuals. Although our capabilities extend beyond the following, we’re most often called to provide technical expertise and assistance with these types of tasks:
- Reliably digitizing analog video or demultiplexing or transcoding footage
- Converting digital video from DVR devices into formats usable for forensic analysis
- Performing clarification techniques such as frame averaging
- Identifying or highlighting persons or objects of interest in video
- Enlarging, sharpening or otherwise enhancing portions of video
- Measuring dimensions of people and objects or distances between points
Video Forensic Tools
Below are a few of the most popular (and most useful) applications used by video forensics professionals.
- VideoInvestigator, VideoActive & AutoMeasure
- Motion DSP Ikena processing and enhancement suite
- Intergraph Video Analyst – incorporating VISAR
- dTective, dCoder, dPlex, dVeloper, MAGNIFi
- Ocean Systems Clear ID for Adobe Photoshop
- Forevid open source forensic analysis software
- Amped Five editing, filtering and clarification software
- Clarifying Technologies forensic filtering
- Signalscape StarWitness Freeze Frame
Audio Forensics
Audio Forensics is the scientific analysis, processing and interpretation of audio sources. It also includes the authentication of audio recordings, enhancement of audio clarity, improvement of intelligibility, speaker identification, voice printing, filtering of unwanted sounds, transcription of speech, and the identification and elimination of known and unknown exemplars from recordings
Common Audio Forensic Tasks
Intertel has the capability to attend to almost any forensic audio-related request. Our services are most commonly requested to assist with or to provide expert advice or testimony with regard to:
- Reliably digitizing audio recordings – typically in lossless formats
- Filtering out hissing, clicking and popping sounds
- Blocking out or quieting ranges and specific frequencies
- Isolating and removing unwanted constant tones or tone patterns
- Performing directional noise cancellation
- Normalizing voices so that each audible person is heard at equal volumes
- Smoothing sounds that border nearly inaudible gaps
- Recovering speech that is masked by distortion, interference and background noise.
- Authenticating audio tapes – including the detection of splicing, over-recording or editing
- Spectral and voice print analysis
- Assessing acoustical compliance of noise in occupational settings
- Measuring the audibility of speech, alarms, sirens, or other sounds at a particular place/time
- Identifying and locating sound sources
- Analyzing gunshot acoustics to identify the weapon and estimate the firing location
Image Forensics
Image forensics is concerned with evidence obtainable from pictures, illustrations, sketches, diagrams, graphics and other imagery. An important part of image forensics involves authenticating photographs (determining whether they’re genuine), detecting alterations, identifying people or places depicted, and verifying the device, time, place and creator of an image.
Common Image Forensics Tasks
- The extraction and analysis of metadata, including EXIF, IPTC, XMP, TIFF and geotags
- Camera “ballistics” to determine what device was used to capture an image
- Carving, recovery and analysis of images or fragments from systems and storage media
- Image authentication and tamper detection
- Using quantization fingerprinting, error level analysis, etc, to detect altered images
- Performing steganalysis to identify information concealed within images (steganography).