Closed-circuit television (CCTV) plays a major role these days in the prevention and detection of crime. It can also provide evidence of a defendant's actions which may be crucial in supporting their innocence. We can enhance CCTV video footage in many ways without losing the integrity of the coverage. We can adjust the colour balance to eliminate the orange glow of street lighting or other colour casts. Basic enhancements include, colour balance, sharpness, brightness and contrast adjustments. It is possible to enlarge specific areas of the footage. Slowing down or speeding up of footage to match real time. We can accept CCTV from VHS tape or digital files. Conversion to & from DVD/VHS can be completed.
Photography & Still Images
We can extract still images from CCTV footage to show events frame by frame. The images can be enhanced and be presented in a photograph album and can be viewed along with the enhanced CCTV footage. Photograph enhancement and analysis, restoration and digital photo compositing are also services we can offer. Lines of sight can also be obtained from images.
Crime scene locations, measurements and lines of sight
Our expert can attend a scene of crime, take images, videos and measurements as required. Albums can be produced and DVD’s of still or moving images.
The Importance of Original Video Recordings
The following two images are captures of the same frame from a video recording. They are exactly the same right?
Wrong, though you could perhaps be forgiven for thinking so. The first image is from a high definition video recording. The second is from the same recording, downscaled (reduced in resolution) to allow the video recording to be copied to a standard viewable DVD disc. Downscaling is routinely used when evidence is prepared for court because for high definition video, Blu-Ray discs must be used instead of the almost universally playable DVDs. The ClickShare equipment now fitted in courts may be used to play media from a laptop, but most laptops are not equipped with Blu-Ray drives and so DVDs are still widely used.
But does it matter?
Many, if not most, CCTV security systems now record images in high definition, as do smartphones and dashcams. For many purposes, images at DVD (standard definition) quality are perfectly adequate. Where fine detail far from the camera, such as a registration number, for example, are important, it certainly does matter. The images below show the same area in each of the above examples blown up to look at the registration plate of the black car on the left:
The number plate is clearly visible in the first image from the HD video. The second image is from the downscaled DVD. Facial features, small objects (such as knives) in the hand and identifying marks on clothing, for example, are all subject to the same loss of quality when downscaled - this list is by no means exhaustive.
Without getting too technical, zoomed HD video can be written to a standard DVD provided the area of the HD video being looked at is small enough, and can then be replayed in the conventional way. The Police, when they copy evidential video, are required under Home Office guidelines to copy it, where possible, in its ‘native’ format and should always retain master and working copies of their original download. The above example illustrates why, if we ask for the original video download we really need it. We are not trying to complicate things for you but simply trying to do the best for your client. Where it would have been advantageous to have used original footage and this has not been provided, this will always be reflected in the report we produce, particularly where such footage has been specifically requested.
Presentation of Video Evidence in Court
We will normally provide processed video evidence in the form of one or more DVDs, but can if requested produce it in another format (usually this would be .mp4) for those who are happy with presenting it in this format using the ClickShare system. Home Office guidance on the on use of ClickShare can be found here.