CCTV Evidence Export: Video Formats, Timestamps and Playback Checks

CCTV evidence export is complete only when the intended recipient can open the correct recordings, follow the relevant event and understand the timestamps. A successful download message does not prove that every camera is included, that the file contains the required detail or that the recorder's displayed time matches the incident timeline.

For New Zealand installers and site managers, export should be a documented operating procedure tested at handover. This guide covers file formats, clock checks, playback and a practical transfer record. It complements our retail CCTV planning guide, which focuses on camera placement and recorded scene quality.

Preserve the incident before investigating the export

Establish the approximate incident time, location, relevant cameras and the person authorised to handle the request. Preserve the relevant recordings promptly using the recorder's supported process so ordinary retention does not remove them. Retain useful context before and after the incident rather than selecting only the most dramatic few seconds.

Keep a short incident record: site, reference number, recorder identity, operator, date, cameras and requested period. Note whether recording was continuous or event-based and whether known outages affect the window. Do not assume an empty search result means nothing happened: it can also reflect the wrong camera, clock offset, event filter or recording schedule.

Axis's video evidence handling guidance stresses protected recordings, documented procedures and system validation. Apply the same operational principle to the installed platform without assuming that an Axis feature exists on another recorder.

Understand the container, codec and export package

A filename ending in MP4 identifies a container, not a guarantee of playback on every computer. The video and audio inside still need supported decoders. Ask what the receiving organisation can accept, then test the actual exported file on its intended viewing environment. Renaming an extension does not convert the recording.

Where the platform supports it, preserve its native export and provide a separately labelled convenience copy when requested. Do not describe a converted file as an untouched export. Keep associated folders and sidecar files together until the manufacturer's instructions establish which components are necessary.

For the UniView NVR502-08B-P8-IQ recorder, confirm the supported export package, player and verification options against the installed firmware and operator manual.

Use the correct player and verify the result

Uniview's official EZPlayer download page describes support for TS and MP4 recordings, synchronous playback and watermark detection. Obtain software from the manufacturer or an approved source. Record the player version and check the package on a suitable workstation before handing it over.

Other platforms use different tools. For example, the AXIS Camera Station Pro manual documents ASF, MP4 and MKV exports and AXIS File Player. Its digital-signature verification and signed-video features are distinct. Do not promise equivalent verification on UniView, FERN360, Dahua or TVT solely because they can export video.

A useful test goes beyond opening the first frame. Play the beginning, key event and end; seek to different positions; confirm duration; and inspect any split-file boundaries. Review moving subjects at normal speed. Check audio only where it was lawfully captured, relevant and intended for disclosure. Record whether the viewing machine needed additional software or permissions.

Record timestamps without rewriting history

Identify which time you are reading: the camera's visible overlay, the recorder search timeline, an export player's display or the operating system's file-created time. They may describe different things. A file-created timestamp is not a substitute for the recorded event time.

Record the configured time zone, daylight-saving setting, clock synchronisation arrangement and observed offset against a trusted reference. In New Zealand, distinguish NZST from NZDT explicitly when documenting a local event. Around a daylight-saving transition, record enough context to identify the intended occurrence of any repeated local time.

For example, if the recorder displays 14:28:00 when the reference clock shows 14:30:00, document that the recorder appears two minutes slow at the observation time. Search the appropriate earlier recorder time and verify the incident against scene content. That single observation does not prove the same offset applied throughout an earlier period.

Do not change the clock first and then try to explain the old footage. Preserve the incident and record current settings and observations before making any authorised corrective change. Investigate clock jumps, restarts and cameras with different overlays when building a multi-camera sequence.

Check every camera and the recorded stream

For cameras such as the FERN360 FGSIP-P5TMVSA-27135, verify the actual recorded detail and camera-to-recorder compatibility during commissioning.

Use a camera map rather than filenames alone. Record channel number, camera name and physical view. For an incident crossing several areas, build a sequence showing where each recording starts and ends. Document gaps honestly. A synchronised player can help comparison, but it cannot correct clocks that were wrong at capture.

Check whether the export uses the intended recorded stream rather than a lower-detail alternative. Compare a representative frame with recorder playback at the same time. If faces or number plates were never recorded clearly, changing container or enlarging the file cannot recover missing scene detail.

Considering the UniView NVR502-16B-P16 or another model in the UniView NVR range? Include a witnessed export and independent playback test in the acceptance criteria.

Create a transfer record that another person can follow

Keep the preserved export in controlled storage and perform routine viewing on a working copy. A file manifest should identify filenames, sizes, camera mapping, time windows, export format, operator and export time. Where your evidence procedure uses SHA-256 hashes, calculate them on the preserved files and compare them after transfer. Matching hashes show matching bytes between those points; they do not independently prove that the camera clock was accurate or the scene was unaltered before export.

Record who received the package, when, by which approved transfer method and whether receipt and playback were confirmed. Use access-controlled storage and an appropriate secure transfer route. Do not put identifiable footage into public links, personal messaging accounts or an unapproved online conversion service.

Preservation and disclosure are separate decisions. The Privacy Commissioner's guidance on individual CCTV access requests says to secure requested footage promptly and assess requests individually. It also distinguishes these requests from Police requests. Follow the appropriate process for the recipient and purpose. If redaction is required, create a documented disclosure copy and protect the preserved material separately.

Example CCTV evidence transfer record

Use the following fictional example as a starting point for your site procedure. Replace each entry with observed information and maintain a separate manifest for every exported file.

Keep the completed record with the preserved export. Label any redacted or converted viewing copy separately and document its source and changes.

Use this export acceptance checklist

1. Confirm authority, incident reference and the relevant cameras.
2. Preserve the required period, including useful context.
3. Record recorder, firmware, clock settings and observed time offset.
4. Export using the platform's supported method and retain required package files.
5. Check every camera, start time, end time and split-file boundary.
6. Open the package on an approved independent workstation.
7. Verify player version, picture detail, relevant audio and any supported integrity result.
8. Create the manifest and complete the required custody or transfer record.
9. Transfer securely and confirm receipt and playback.
10. Apply the organisation's retention and deletion procedure when preservation obligations end.

Frequently asked questions

Is MP4 always the best evidence format?

No. It can be convenient, but the recipient's requirements, available metadata and the platform's supported preservation options determine the package. Test the actual file rather than relying on its extension.

Should I correct a wrong recorder clock before exporting?

Preserve the incident and document the clock, settings and observed offset first. Make a later authorised correction with a clear record of what changed.

Does a matching SHA-256 hash prove the footage is authentic?

It proves the compared files have matching bytes to the practical strength of that hash. It does not establish the accuracy of the original scene, clock or earlier handling.

Can a phone recording of the monitor replace an export?

It is not an equivalent preservation method. It introduces another recording stage and may omit detail, metadata and continuity. Obtain the supported export wherever possible.

Plan export and handover with Essential Security Supplies

Include operator training and a witnessed export test in your CCTV specification. Ask Essential Security Supplies for recorder and storage specification help, providing camera count, retention target, existing recorder details and the recipient's playback requirements.