Specialist image
& video examination.

A JPEG image, with its claimed camera source or file history where available.

• Compare compression-setting tables against known camera, editor, export-preset and sharing-platform references.
• Cross-check other encoding tables, colour subsampling, thumbnails and metadata layout.
• Compare those observations with the camera source claimed in embedded metadata.

These patterns identify encoding families, not individual devices. Re-encoding may replace original settings; a matching family does not prove camera origin. Reference coverage is reported with the result.

One questioned image; confirm format support before submission.

• Map local recompression differences, noise level, statistical texture and resampling periodicity.
• Compare a suspected pasted object, replaced face or altered number plate with nearby material.
• Apply a stated false-alarm threshold to the one supported region-flagging map; keep other maps unscored.

Texture, focus and compression can change these statistics. Other maps did not reliably separate planted splices in validation and are displayed without scores. A flag identifies a place to examine, not proof of alteration.

One questioned photograph; confirm format support before submission.

• Inspect fine-detail periodicity that can arise from display pixels or print halftones.
• Assess the strongest colour-channel signal while excluding JPEG-grid patterns and scene edges.
• Read the indicators against thresholds established on authentic photographs, with softness and tonal context.

Regular scene patterns can create similar peaks, and careful recapture may leave little trace. These are indicators for review, not a definitive screen-versus-camera or print-source verdict.

Several camera recordings with suitable shared-frame, visible-clock or audio-event anchors.

• Use shared events, examiner-transcribed on-screen clocks or sufficiently strong audio correspondences.
• Estimate offsets and drift when anchors are far enough apart to support them.
• Flag disagreeing methods rather than silently average incompatible estimates.
• Keep unanchored cameras unsynchronised and fingerprint the history of anchor changes.

A common timeline is an estimate with uncertainty, not an independently established capture clock. Weak correspondences are discarded; missing anchors are not guessed.

Native footage with defensible timing and suitable geometry, road markings or examiner-confirmed device telemetry.

• Check native timing and re-encoding before deciding whether a speed estimate can be reported; refuse processed derivatives.
• Use suitable positions between two marked frames, verified road-marking observations or confirmed device telemetry.
• Cross-check independent approaches where the available evidence supports them.
• Report worst-case bounds, probability-based intervals and the two-person sign-off state.

Some recordings cannot support a speed figure. Geometry, timing, reference assumptions and telemetry provenance must be defensible. Indicative estimates are not equivalent to a fully supported measurement.

A compatible encoded video stream; coverage depends on the codec.

• Read block-level decisions from the encoded stream and show sampled motion fields.
• Display block-type, zero-motion, compression-setting and motion-discontinuity maps.
• Flag a textured region that remains motionless while the surrounding camera view moves, only where the required frame type and camera motion are present.

Other maps are displayed for examination without scores. Encoding choices, scene structure and camera motion affect interpretation. Coverage includes supported AVC and older MPEG streams; modern high-efficiency exports are not supported by this workflow.