| |
 |
|
|
Science Forum Index » Image Processing Forum » Regarding Potential Video Fakery in R. Kelly Case...
Page 1 of 1
|
| Author |
Message |
| aruzinsky... |
 Posted: Fri Jun 13, 2008 6:02 am |
|
|
|
Guest
|
Is it possible to convert a video tape (of the case type) into a
series of digital still frames and then back to video tape without
being detectable?
If not, what is the approximate PSNR or whatever metric of error of
the current best process? |
|
|
| Back to top |
|
| Martin Leese... |
| Posted: Fri Jun 13, 2008 7:46 pm |
|
|
|
Guest
|
aruzinsky wrote:
Quote: Is it possible to convert a video tape (of the case type) into a
series of digital still frames and then back to video tape without
being detectable?
If not, what is the approximate PSNR or whatever metric of error of
the current best process?
A news story stated:
"Expert witnesses for the prosecution
said that the VHS tape, whose origin is
unknown, was a multigeneration copy but
had not been tampered with."
My understanding is that the defense did not
argue that the tape wasn't genuine, but that
the man in it was not R. Kelly.
Given that the tape is a copy of a copy of a
.... then no metric is going to help.
--
Regards,
Martin Leese
E-mail: please at (no spam) see.Web.for.e-mail.INVALID
Web: http://members.tripod.com/martin_leese/ |
|
|
| Back to top |
|
| aruzinsky... |
| Posted: Sat Jun 14, 2008 6:41 am |
|
|
|
Guest
|
On Jun 13, 6:46 pm, Martin Leese <ple... at (no spam) see.Web.for.e-mail.INVALID>
wrote:
Quote: aruzinsky wrote:
Is it possible to convert a video tape (of the case type) into a
series of digital still frames and then back to video tape without
being detectable?
If not, what is the approximate PSNR or whatever metric of error of
the current best process?
A news story stated:
"Expert witnesses for the prosecution
said that the VHS tape, whose origin is
unknown, was a multigeneration copy but
had not been tampered with."
My understanding is that the defense did not
argue that the tape wasn't genuine, but that
the man in it was not R. Kelly.
Given that the tape is a copy of a copy of a
... then no metric is going to help.
--
Regards,
Martin Leese
E-mail: ple... at (no spam) see.Web.for.e-mail.INVALID
Web:http://members.tripod.com/martin_leese/
You didn't answer my questions.
Expert witnesses in court are a sham in this case and most other
cases. To be an adequate video expert witness, one must be able to
answer my questions accurately and provide verifiable evidence.
Otherwise, no adequate video expert witnesses exist.
I am trying to decide whether all cases of that type, in which video
evidence has no supporting verbal testimony, fingerprints, DNA
evidence, etc to link the defendent to the video, should be thrown out
of court. I, a resident of Crook County, IL, helped fund that
prosecution which was a complete waste of my tax money. I want to
prove that that prosecution should never have been attempted. Do you
find government waste acceptable? |
|
|
| Back to top |
|
| Nomee... |
| Posted: Tue Jun 17, 2008 2:06 am |
|
|
|
Guest
|
It is possible to convert an analogue video tape into digital frames.
The second thing is easy and it is possible to combine these frames to
form a video sequence.
The loss of accuracy in this case is unavoidable when converting to
digital from analogue. This loss can be reduced by using a high frame
rate and digital quality. There are even algorithms that can inpaint
missing frames. A recently published paper on inpainting has shown
that a complete missing frame can be produced from 30 or more frames
with an accuracy of 85%. |
|
|
| Back to top |
|
| aruzinsky... |
| Posted: Tue Jun 17, 2008 6:11 am |
|
|
|
Guest
|
On Jun 17, 6:06 am, Nomee <farrukhsubh... at (no spam) gmail.com> wrote:
Quote: It is possible to convert an analogue video tape into digital frames.
Obviously, otherwise, people wouldn't be converting their VHS
recordings to DVD.
Quote: The second thing is easy and it is possible to combine these frames to
form a video sequence.
The frames are a video sequence and no conversion is necessary.
Quote: The loss of accuracy in this case is unavoidable when converting to
digital from analogue. This loss can be reduced by using a high frame
rate and digital quality.
The frame rate of NTSC VHS for playback is FIXED at 29.97 frames/
sec.. Two interlaced raster scans comprise a frame. For purposes of
fakery, in converting from VHS to digital frames, it would probably be
better to use each of the interlaced raster scans as a separate frame
which would effectively double the frame rate. I doubt that
conventional methods such as used in DVD recording do this. Also, I
know that extra visual information can be stored between VHS frames
because I have seen it when my TV lost vertical hold. To successfully
digitally fake VHS, information between frames and soundtrack would
have to be preserved and/or faked. |
|
|
| Back to top |
|
| |
|
Page 1 of 1
All times are GMT - 5 Hours
The time now is Sun Nov 23, 2008 2:04 pm
|
|