Feature Focus: Date/Time Offset

Making corrections to an incorrect date/time within DVR Examiner can be a little confusing at first, especially with all the variable settings that DVRs have. Read through this blog for some tips on how to use the DVR Examiner offset feature adjust for incorrect timestamps and easily identify your event of interest.

To make the most of the date/time corrections within DVR Examiner, we recommend you capture some critical date/time information from the DVR before you begin your recovery:

• The current date/time according to the DVR
• The current time zone setting of the DVR (if there is one, not all DVRs use time zones)
• The current DST (Daylight Savings Time) settings of the DVR. (Not all DVRs support DST, or may require special configuration to use it)
• The current date and time according to a reliable source, such as a cell phone

While circumstances do not always allow for recording this information, having it will make it much easier to make adjustments in DVR Examiner when filtering your clips.

With this in mind, we can move forward with making adjustments to the date and time in DVR Examiner. If the DVR utilizes a time zone, you will see an option to select the appropriate time zone in DVR Examiner. DVR Examiner does not know if the time zone set by the DVR is the correct time zone, so the software will default to UTC-0 and let you choose the appropriate time zone. If the time zone was set correctly on the DVR, the time zone in DVR Examiner needs to be changed to match the DVR. If the DVR time zone was set incorrectly, the time zone in DVR Examiner will need to be set to the correct time zone for the event you are looking for.  For example, if you are on the East Coast trying to find a robbery on a DVR from the West Coast, but the DVR time zone is set to Central, you will need to set the time zone in DVR Examiner to UTC-8 (West Coast) to match the time of the crime. The time zone drop down in DVR Examiner is also where you will need to specify if daylight savings time was enabled on the DVR. If DST was enabled, choose the time zone option that reflects this, and DVR Examiner will automatically make corrections for daylight savings time.

Now that the time zone is out of the way, we can look at making corrections for the DVR date/time.  At first, this may seem more complex than it is. However, the offset option is just telling DVR Examiner what difference to apply to any timestamp recovered from the DVR. The date and time entered for the DVR date/time and Actual date/time do not actually matter. What’s important is the difference between the two values. A good strategy would be to input the recorded date and time from both the DVR and the current time when you recovered the device.

The timestamps DVR Examiner recovers from the DVR are going to be the same no matter what because that is the information the DVR stored on the hard drive. The offset feature simply adds an adjusted timestamp for the “actual” date and time based on the values you put in the configuration. For example, if you say the DVR date/time is 2 days behind the actual date/time and DVR Examiner recovers a clip from December 22^nd, 2013, DVR Examiner will add an adjusted timestamp for that clip indicating that this clip actually occurred on the 24^th of December 2013.

The last offset option available in DVR Examiner is the “per clip offset” available in the side bar on the “clip list” tab.  There are two examples in which you might use this feature. First, if you are working with data from a system that utilized IP cameras, the date/time offset could be different per camera. Because IP cameras encode the timestamp information on the camera itself and then send that information to drive to be stored, the possibility exists for there to be a different timestamp per camera and for all those timestamps to be wrong. The per clip offset in DVR Examiner gives you the chance to correct this by filtering per channel, then selecting all the clips for that channel and applying the appropriate offset.

The second use for the per clip offset wold be if the DVR date/time was set differently for the first half of the recovered clips than the second half. For example, the DVR owner realized half way through filling up the hard drive that the date/time was set wrong and then fixed it for the second half of the recordings. With DVR Examiner, you can select the first half of the recovered clips and apply an offset to those clips without changing the second half.

I hope this blog has helped clarify a few things about the Date/Time Offset feature in DVR Examiner. If you have any questions or suggestions please don’t hesitate to reach out to us at support@dmeforensics.com.