afredson 0 Posted April 3, 2010 can dates and times on cctv images be tampered ? how will someone know if it has been tampered , for example i have the time for a first picture at 20:09:16.362 at the right side its shows 6936 ,the second picture 20:12:12.364 and at the right side its shows 14792 . iam a bit suspicious how this number has gone up from 6936 to 14792 within 3 mins ??? Regards Share this post Link to post Share on other sites
securitymonster 0 Posted April 3, 2010 Most any DVR has a menu option to adjust your Date/Time. Likewise, if its networked, you should have remote admin ability to adjust the Date/Time as well. The DVR is only as protected and you make it, both physically and electronically. Daylight savings just happened for us recently, maybe this had some effect on your date/time? Some DVR's have the ability to auto adjust for DST. Share this post Link to post Share on other sites
afredson 0 Posted April 3, 2010 Most any DVR has a menu option to adjust your Date/Time. Likewise, if its networked, you should have remote admin ability to adjust the Date/Time as well. The DVR is only as protected and you make it, both physically and electronically. Daylight savings just happened for us recently, maybe this had some effect on your date/time? Some DVR's have the ability to auto adjust for DST. Hi this is just a cctv evidence and image print out was produced , im wondering is it possible for someone to tamper with the dates and times on cctv images ?? this image is taken from the same camera ( time on the first picture is 20:09:16.362 at the right side its shows 6936 ,the second picture 20:12:12.364 and at the right side its shows 14792) i am a bit suspicious how this number has gone up from 6936 to 14792 within 3 mins ??? Share this post Link to post Share on other sites
tomcctv 190 Posted April 3, 2010 Most any DVR has a menu option to adjust your Date/Time. Likewise, if its networked, you should have remote admin ability to adjust the Date/Time as well. The DVR is only as protected and you make it, both physically and electronically. Daylight savings just happened for us recently, maybe this had some effect on your date/time? Some DVR's have the ability to auto adjust for DST. Hi this is just a cctv evidence and image print out was produced , im wondering is it possible for someone to tamper with the dates and times on cctv images ?? this image is taken from the same camera ( time on the first picture is 20:09:16.362 at the right side its shows 6936 ,the second picture 20:12:12.364 and at the right side its shows 14792) i am a bit suspicious how this number has gone up from 6936 to 14792 within 3 mins ??? what you are looking at is the time plus water mark. Share this post Link to post Share on other sites
afredson 0 Posted April 3, 2010 Most any DVR has a menu option to adjust your Date/Time. Likewise, if its networked, you should have remote admin ability to adjust the Date/Time as well. The DVR is only as protected and you make it, both physically and electronically. Daylight savings just happened for us recently, maybe this had some effect on your date/time? Some DVR's have the ability to auto adjust for DST. Hi this is just a cctv evidence and image print out was produced , im wondering is it possible for someone to tamper with the dates and times on cctv images ?? this image is taken from the same camera ( time on the first picture is 20:09:16.362 at the right side its shows 6936 ,the second picture 20:12:12.364 and at the right side its shows 14792) i am a bit suspicious how this number has gone up from 6936 to 14792 within 3 mins ??? what you are looking at is the time plus water mark. but can this be altered or tampered ?? the water mark has gone up within 3 mins ? what else do i need to look for ? Share this post Link to post Share on other sites
tomcctv 190 Posted April 3, 2010 i take it you have been court on camera and you have pictures ??? yes water marks can be removed when footage has gone to another format. but both photos have a water mark so the footage they are taken from is water marked and cant of been altered Share this post Link to post Share on other sites
Scruit 0 Posted April 4, 2010 I thought watermarks were invisible... Yes, footage can be manipulated. It's up to the prosecution to convince the judge and jury that is has NOT been manipulated. Whether or not the defense will challenge a video is based on several factors: - Has the footage been copied from one format to another? How many times? - Is the video in an insecure format that can be manipulated, such as AVI/MPG? - Is the video produced by a system that uses a watermark, and the watermark is invalid or missing? - Is it worth the cost of hiring an expert to argue the video? - etc Whether or not the Judge/Jury will trust the footage is also based upon several factors: - Did the person who is validating the images have full custody and control over the video at all stages? - Is the video in a secure format? ie Proprietary codec that can't be altered in video editing software. - Is the watermark present? - Is the person presenting the evidence someone that the judge/jury is going to believe? Whereas there are no absolutes, you can be reasonable assured that a video in a shoplifting case will face less scrutiny than in a murder case. In a soplifting case it's generally not worth hiring an expert to validate or challenge video even if it's grainy VHS stuff. In a murder case you'd better have all you ducks in a row (good frame rate, high quality, good resolution, documented chain of custody etc) because most folks will pay anything to discredit the video. Real life examples below... I don't know what the numbers are after the date/time you described. Could be frame numbers? Field numbers? Camera ID (if the video footage shows multiple cameras)? The watermarks that I'm aware of generally use secret data hidden in the video stream. They are hidden in a way that if the video is copied to a new format then the data is lost, so software that validates the watermark will identify if the video is original or not. Real life example 1: One of my videos was used in a USPSemployment termination arbitration hearing. The video was exported to DVD by playing it back on DVR and using a TV capture card. The video was low frame rate (4fps) but good resolution. The content of the video was not challenged, although an attempt was made to exclude the video based upon invasion of privacy. The arbitor ruled that because the video was taken outside my house in view of the street there was no expectation of privacy, therefore the video was allowed. CPCam CPD576W DVR. Real life example 2: Another of my videos was used in a prosecution of a 3rd degree misdemeanor criminal mischief case. The video was exported using the export-to-AVI function in the USB playback console (Aver EB1304MOB). That AVI was rendered down to 90% original size because the time/date stamp was not visible on a television screen (slighty off the edge), then burned to DVD. The prosecutor made it it clear that I would have to validate the video and show chain of custody. The video was never challenged and the defendant entered into a plea hearing after consulting with defense attorneys. He said words to the effect of; "They said I would be paying them to defend me and I'd still lose." Real life example 3: Another video, exported in the same way/same DVR as example 2, was used in a felony prosecution for theft/burglary. The defense issued a subpoena for a expert to come and testify about the video. The prosecutor stated this was just sabre-rattling during the plea negotiations. The defense never alluded to what they wanted their expert to testify about. The video was only a very small part of the case, and even a successful challenge would not have altered the outcome of the case, so the defendant accepted a plea deal where he served 3 years in jail. My lessons learned: Next time I submit video it will be a data DVD that contains the .DVR and .AVI files. The .AVI will be for convenience as it can be played in media player, however any serious case may see the .AVI challenged as it can be manipulated and has no watermark. The .DVR file will have the watermark and any defense expert will see that and will be unlikely to succeed in a challenge on the authenticity of the video. Share this post Link to post Share on other sites
kensplace 0 Posted April 4, 2010 can dates and times on cctv images be tampered ? how will someone know if it has been tampered , for example i have the time for a first picture at 20:09:16.362 at the right side its shows 6936 ,the second picture 20:12:12.364 and at the right side its shows 14792 . iam a bit suspicious how this number has gone up from 6936 to 14792 within 3 mins ??? Regards View the original footage, what that happens to the time and the number, see if anything is amiss. Perhaps the number is showing each individual frame number, 25fps for pal or 30fps (frames per second for NTSC, as the are interlaced, ie made up of two pictures per frame, the number could be going up 50 or 60 each second... Without knowing what the other number is, or what its actually doing in the footage, its hard to know for sure. Best to just view the original footage, and that should shed light on the matter. Share this post Link to post Share on other sites
hayden 0 Posted April 8, 2010 It represents lapsed time you say 3 minutes...... 180 seconds.... 1st Pic Frame I.D - 6936 Second frame I.D - 14792 Difference = 7856 Frames 7856 Frames / 180 Seconds = 43 Frames Per Second Share this post Link to post Share on other sites
Soundy 1 Posted April 9, 2010 can dates and times on cctv images be tampered ? how will someone know if it has been tampered , for example i have the time for a first picture at 20:09:16.362 at the right side its shows 6936 ,the second picture 20:12:12.364 and at the right side its shows 14792 . iam a bit suspicious how this number has gone up from 6936 to 14792 within 3 mins ??? Regards It's all kind of a moot question without knowing what that number on the right side refers to. Is it a time count? Is it a reference or watermark? Is it a CRC or other sort of authentication mark? Does it maybe indicate other image factors like motion detection, image brightness, etc? Without knowing this, your concerns are baseless, and everyone else's answers (except kensplace's) are just speculation. Share this post Link to post Share on other sites
rfidkaiser 0 Posted April 16, 2010 can dates and times on cctv images be tampered ? how will someone know if it has been tampered , for example i have the time for a first picture at 20:09:16.362 at the right side its shows 6936 ,the second picture 20:12:12.364 and at the right side its shows 14792 . iam a bit suspicious how this number has gone up from 6936 to 14792 within 3 mins ??? Regards It's all kind of a moot question without knowing what that number on the right side refers to. Is it a time count? Is it a reference or watermark? Is it a CRC or other sort of authentication mark? Does it maybe indicate other image factors like motion detection, image brightness, etc? Without knowing this, your concerns are baseless, and everyone else's answers (except kensplace's) are just speculation. Hi Soundy, What made you think that Hayden's answer is a speculation? DG Share this post Link to post Share on other sites
Soundy 1 Posted April 16, 2010 The fact that he came up with the number indicating 43fps recording, which isn't possible with NTSC or PAL video? Share this post Link to post Share on other sites
rfidkaiser 0 Posted April 19, 2010 The fact that he came up with the number indicating 43fps recording, which isn't possible with NTSC or PAL video? Hey, Oops !!! I forgot to notice the value. I reckon maximum FPS for PAL is 25 and NTSC is 30. What is the highest FPS used in surveillance? Share this post Link to post Share on other sites
Soundy 1 Posted April 19, 2010 What is the highest FPS used in surveillance? 25 or 30, depending on whether you're working with PAL or NTSC. There's no benefit to recording at a higher framerate than the video standard provides. In fact, there's not usually any benefit to recording at even HALF that framerate. Share this post Link to post Share on other sites