Courtroom Presentation, Litigation Software : Charles Perez : Trial Presentation Blog

OK - in the previous blogisode my sidekick and ally in presentations Eric Graf exploded many of the make-believe antics that pass for science on those pop cop "CSI" - type soap operas that have the masses convinced that such visual alchemy truly exists.

One of the culprits that I feel has encouraged the feebs who write the CSI tripe is the DVR, or Digital Video Recorder. I've personally witnessed the growth of these machines over the past 5 or 6 years in the surveillance arena and have marveled at the promises made by the manufacturers that hawk them to their unsuspecting customers with the overt promise of the unit being capable of isolating an incident (and any suspect within the incident) and then enlarge said subjects facial features for police identification.

I've had the sad chore of bursting many a security manager's bubble when I point out the REAL limitations of their 32 camera, state of the art, real-time, internet accessable system. I no longer feel the need to let them rest their head on my shoulder anymore while gently rocking them and saying "There, there, it wasn't your fault".

Because, it is their fault. They should know better.

Here's why - Here's Eric's take on what we'll call "The Digital Myth":

DIGITAL IS NOT NECESSARILY BETTER  (Regardless of what you've been told)
 
Actually, I could almost leave out the “necessarily.”  There’s this dirty secret about digital video that they don’t tell you.  Here it is.  Y’ready?
 
To save space, digital video throws out details of the picture that it doesn’t think you’ll miss.
 
It’s really obvious on some internet videos, where you’ll see people’s faces disappear into a detail-less blob.  Trouble is, nearly all digital video, including DVD, DV tape, TiVO, high-definition broadcast, and (especially) surveillance systems, does the same thing to a certain extent, and it messes up our ability to do some of the cool CSI things we actually can do.
 
DVDs are particularly bad about this, particularly if you’re using a consumer-grade recorder, and PARTICULARLY if the original source is VHS.  VHS has a lot of extraneous "noise" in the picture, and extraneous noise tends to confuse DVD recorders into throwing out more of the important details than they ordinarily would.
 
Going from analog to digital also has some hazards not directly related to the nature of digital.  For instance, every consumer grade DVD recorder we have ever tested, without exception, records the video black level incorrectly.  It’s a long story as to why (and if you feel you MUST hear it, you can email me), but the point is that it’s a problem for us, and there’s not a darn thing you can do about it without professional video equipment.  (Side note . . . many DV recorders and computer video cards do the same thing.)  It’s best to send us the original, and if there are DVDs to be made, let us make them.
 
Copying digitally (through Firewire) from DV tape to DVD usually goes better, but there’s still quality loss, especially in the color information, because DVD ditches a lot more of the detail info than DV tape does.
 
YOUR SHINY NEW DIGITAL SURVEILLANCE RECORDER  (It's not what you thought it was)
 
OK, if you have one of these newfangled gizmos, pay very close attention!

Guess how they manage to get a month’s worth of video onto a single hard drive?
 
That’s right.  They toss out everything, even the kitchen sink.  And they record the picture at a horrible resolution setting that guarantees that anything smaller than a Peterbilt won’t be recognizable.
 
If you have your digital device set to record at the maximum time setting, you might as well not waste your electricity.  You will not get ANYTHING useful.  Period.  End of story.  We have a lot of would-be clients who learned this the hard way.  And sadly, most of the salespeople who handle these things don’t bother telling you this, figuring that you’ll assume (incorrectly) that somebody like us will be able to bail you out when the need arises.
 
Change those settings now!   

Go for the shortest time period and the highest quality you can possibly get away with.  Use your own eyeballs and your own common sense.  As already discussed, video does not enlarge well, so if you can’t see it on your screen, there’s a good chance we won’t be able see it on ours either. 
 
If you have everything maxed out and still can’t see stuff, consider rethinking the position and coverage of the cameras.  Yes, you might miss something if you’re zoomed in too tight, but you’ll miss EVERYTHING if you’re zoomed out too wide.  A teeny little blurry picture of a teeny little blurry guy stealing your Bentley isn’t going to help you or the cops or us or the Bentley.  If you’re worried about the Bentley, then zoom in on the Bentley!  Let the Yugo parked next to it fend for itself.

Stay Tuned.. Our next blogisode will have you questioning everything you believed you knew about AUDIO!

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O.K. - forget I used the phrase "video ehancement" in the title. The proper (correct) phrase is "video clarification", but, thanks to all the "pop, quasi-realistic, CSI-Miami, CSI-Las Vegas, CSI-Ad Nauseum garbage" on television I figured you'd recognize the term "Enhancement" since that's the misnomer these fact-challenged programs lead you to believe companies (and underfunded police agencies) are capable of doing. (We'll discuss the sub-par "acting" of David Caruso at a later date).

For the next few "blogisodes" I'm turning over the site to my able bodied wing nut right hand man and audio/video engineer extraordinare Eric Graf  (who works with me at Video Resources, Inc. in the Video/Audio Forensics lab) to explain as simply as possible the why's and wherefore's of video and audio clarification and why it's important for you to know what will and, more importantly, what will not work for you. 

Here's Eric's Video Clarification Blog: (Enjoy!)

The following is a list of random factoids about video.  Hopefully there will be pearls of wisdom herein that will help us better serve you when you get some of that all-important footage that needs enhancing (oops! I mean clarification)..  Warning:  I tend to overuse parentheses (but I’m trying to improve).
 
First of all, you know those TV shows like CSI where they take grainy, blurry, little bitty digital video and enhance it until you can read the serial number on the bad guy’s cellphone as he throws it across the pitch-black parking lot? 

 Guess what ?. . . That’s fake.   (GASP!)  (Take a few moments to catch your breath and then continue reading once your vision returns to normal.. I know - it's a shock.)

Those shows are no more a reflection of real CSI science than James Bond is.  The writers who come up with stuff like that just need some convenient way for the good guys to crack the case, so they make up something silly that they think most viewers will buy.  And most viewers do.  Please don’t be one of them. 

Video doesn’t work like that.  We wish it did.

RESOLUTION - THE CRUX OF THE PROBLEM  (well, one of the many problem cruxes)
 
OK - Here's the basic formula for understanding how video images are displayed on your TV screen/monitor: Standard definition video has very specific limits in resolution: 720 pixels wide by 486 pixels high.  Well, actually, it’s more like 243 pixels high in practice, but that’s getting on a technical tangent, so let’s not go there.  Anyway, that’s much lower than even the most inexpensive analog still camera.
 
What that means is, once something in the frame gets smaller than a certain number of pixels, then that’s it. PERIOD. You aren’t going to be able to see what it is.  The best supercomputer in the world can’t take a solid block of color (which is what a pixel is) and figure out what details within the block made the block come out the solid color it did.
 
That’s the main reason most of the CSI TV stuff is bogus.  It ignores the resolution issue.  We can certainly take a video picture and make things on it bigger.  But they won’t be sharper, or easier to see or read, because video resolution "is what it is". 

Bigger will just mean blurrier, and if you get too big, you won’t even be able to tell what you’re looking at anymore.  Things that are too small just can’t be sharpened or enhanced from a video source.

You know MORE that the writers at CSI!

COPIES AND WHY WE HATE 'EM 
 
Analog video degrades every time you copy it....  A lot.  Often enough so that whatever we’re supposed to be seeing can’t be seen anymore. (Digital Video, when copied correctly, doesn't degrade at all.)
 
Now, we all know that most VHS-based surveillance equipment is poorly maintained and the tapes are reused until they get holes worn in the tape.  It can often be difficult to get the fool things to play back properly.
 
Here’s the deal:  Here at VR, we’re GOOD at getting the fool things to play back properly.  In fact, we have a warehouse full of equipment to do just that.  I can’t tell you how many times we’ve received tapes that wouldn’t play in any VCR in the building except for ONE.  (There’s this one beat up old Philips deck that I’ve rescued from imminent dumpsterization three times here at VR, and now guard with my life.  It’s ugly, dirty, a little sticky, and not of much general use, but it does an amazing job with certain multiplex timelapse tapes.)
 
In extreme cases, we’ve been known to go inside one of our decks and deliberately misadjust it to match a particularly screwy tape.
 
But if you give us a copy, then we’re stuck with whatever happened playback-wise when the copy was made.  Did the copyist forget to set the tracking?  Was there a problem with the signal level going from one machine to another?  Did they run it at the wrong speed and accidentally cut off 2/3 of the content?  We’ve seen all these things, and we can’t fix them if they’re “burned in” (ie, recorded) into the copy.  And even if they did get everything exactly right, it’s still a copy, with degraded quality.
 
And oh yes, on the topic of multiplexed tapes . . . you know, the ones that record lots of full-screen cameras really fast so that they show in a jumbled flicker?  Please don’t have anyone demultiplex them for us.  Reread the part on “copies” and you’ll see why.
 
What’s that?  You say you’re going to copy your tape onto a DVD?  Just as bad, I’m afraid.  Possibly even worse!
Catch my next post and I'll tell you why........

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