is the date-time counter on video footage reliable?

Hello everyone,

With many different types and shapes and appearance, all video footage have some type of date-time counter on one corner of the screen, along with the camera number. In some DVRs, this information can be adjusted to appear or not.

So, this date-time counters on footages do not seem to be editable like the exif data in pictures, it seems embedded in the video and seems not like a seperately editable field. However my question is that can we trust these counters or should we know that there is still the possibility that any date-time counter can be placed on footages?

Regards,

It greatly depends, AFAIK in some cases it is a "superimposed image", particularly if it is (as often happens) a whitish set of digits on a blackish rectangle, in theory nothing prevents from superimposing a black rectangle on a video and the re-superimposing a new set of digits, there are also Commercial programs to do that (example)
http//www.svdtpro.com/

BUT HOW EXACTLY did you check for the video metadata?

A number of formats do store timecode, and there are forensic tools to check those as well, the data "corresponding" to Exif is called Riff
http//veresoftware.com/blog/?p=364

jaclaz

Jaclaz, It is a mp4 file coming from a surveillance DVR.

I checked for the video metada with Phil Harvey's Exif Tool GUI but no detailed information came out. it was only file sytem date-time stamps that came out and the exif tool said "file format error".

Then I tried it with mediainfo, and not much metadata shown, in the "container and general information" section, it shows MPEG-PS911 MiB 3 min 50 s, overall bit rate332 kb/s
1 video streamAVC

And in the "First video stream" section, it shows 326 kb/s, 704*576 (1.222), AVC (baseline@L2) (1 Ref Frames)

So, I think metadata must have been stripped off becuase of format conversion during export from the recording system.

The simple answer in my opinion would be, not so much. The DVR itself may be off, the time server it's connected to could be off (rare but possible), or it may not have timestamps at all! Your best bet is probably to go through the header to see what you can find, but that may not be helpful depending on the DVR.

Nothing as "encoded date" or as "tagged date" in Mediainfo?
*Like*
http//forum.videohelp.com/attachments/33906-1443764425/Before.jpg

try checking directly the mvhd data (if any) directly with a hex editor/viewer
http//forum.videohelp.com/threads/373362-Change-Time-Stamp-on-mp4-video?p=2411950&viewfull=1#post2411950

jaclaz