The issues raised below follow on from Jim’s post over at http://forensicphotoshop.blogspot.co.uk/2014/09/visionbases-previs-vs-ocean-systems.html
When I received the PREVIS information, I too was a little confused at a number of the included statements and after receiving a phone-call from a colleague asking similar questions I thought that some clarification may be required.
I fear that the documentation over simplifies the evidential requirements of Digital Multimedia Evidence and, if not fully understood, they could cause some difficulties as an investigation progresses.
All quotes taken from:
In order to deal with some of the issues, I have asked Visionbase for some guidance on the statements:
“Many DVR systems suffer from providing a low-resolution, low-quality compressed file export, this is due to limited or low-cost video compression libraries or licenses used by the manufacturer. In addition, complications of players and codec’s being exported incorrectly mean it can often be a lot quicker to capture the required camera data on location even if the DVR has an export facility.”
“DVR’s exporting via USB instead of CD/DVD present the risk of transferring viruses or malware. DVR hardware in most instances are capable of recording and displaying a much clearer and sharper image when viewed via video, VGA and HDMI, PREVIS takes advantage of this fact allowing recording of the audio and video in original high-resolution at up to full HD 1920×1080 pixels.”
“CREATE EVIDENCE IN UNIFORM FORMAT”
I will post again when I have further….
I have received a concise reply from Visionbase regarding my concerns on the evidential standards reported. I do not believe it to be productive to post that response here.
Regardless of manufacturer or device, the evidence is always the original recorded data. That is the first step in any Digital Multimedia Evidence (DME) acquisition. To make the decision not to obtain this data requires competency in order for a court to dismiss any breach of process claim. The competency of the person making this decision will also be tested to ensure that the recorded evidence can be relied upon and that it is a true and accurate representation of an event. If the video data can not be interpreted correctly, due to any loss of information, then the evidential worth of such evidence could be questioned.