Technical guide by Roberto Ruggeri, forensic audio specialist. Last substantive review: 28 August 2026. Codec lineage is a practical way of describing the sequence of encoding, decoding, transcoding, export and re-encoding stages that may have shaped an audio file before examination. The central question is not simply “which codec is this file using now?” but…
An audio artifact is a feature introduced or materially shaped by the recording, conversion, coding, transmission, processing or playback chain rather than by the acoustic event being examined. In forensic audio, that distinction matters because a click, tonal component, distortion, short gap or smeared transient can be misinterpreted if its technical origin is not considered.…
Separating an audio stream from a video file is not one single technical operation. The result depends on whether the audio is stream-copied, decoded to PCM, or decoded and re-encoded. When saved as a separate output, audio extracted from video is a newly created digital file; stream copy can preserve the compressed audio bitstream without…
Technical guide by Roberto Ruggeri, forensic audio specialist. Last substantive review: 27 August 2026. A spectrogram is a time-frequency representation of sound. Time runs horizontally, frequency runs vertically, and color or brightness represents the relative strength of spectral energy at each time-frequency point. The exact quantity and scale depend on the software and display settings,…