Reference Profile
Definition
A database of known parameter values built from recordings made with the suspect device under controlled conditions. Comparison of the questioned video against the reference profile is the core analytical step in source camera matching.
- Built from
- Controlled recordings made with the suspect device
- Compared against
- The questioned video's parameters
- Application
- Source camera matching
Common questions
Why must the reference profile be built with the actual suspect device rather than the same make and model?+
Sensor-level artefacts such as fixed pattern noise are unique to an individual sensor, not just the camera model, so a profile built from a different unit of the same model would only support model-level, not device-level, attribution.
Can firmware updates affect the validity of an existing reference profile?+
Yes, an update that changes the camera's processing pipeline, such as noise reduction or compression settings, can shift the parameters being matched, so a reference profile built before an update may need to be rebuilt to remain comparable to post-update questioned footage.
Related terms
- Bitrate Profile
- The pattern of bitrate variation across time in a variable-bitrate recording. A camera's rate-control algorithm allocates more bits to complex scenes and...
- Codec Fingerprint
- The characteristic pattern of encoding decisions made by a camera's firmware when compressing video: the specific H.264 or H.265 profile and level,...
- Colour Pipeline
- The sequence of transformations applied to raw sensor data to produce the encoded video signal, including white balance, gamma curve, colour space...
- GOP (Group of Pictures) Structure
- The pattern of I-frames, P-frames, and B-frames in a compressed video stream. Different cameras use different GOP lengths and frame-type ratios, which...
- PRNU (Photo Response Non-Uniformity)
- The unique pattern of pixel-level sensitivity variations in a camera sensor, used as a device fingerprint. A genuine camera-original image carries the...