Posted by George Hammond on 10/13/05 10:49

On Thu, 13 Oct 2005 11:46:00 +0200, "erik" <erik@somewhere.com> wrote:

>"George Hammond" <ghammond1@earthlink.net> wrote in message
>news:900qk1lvm0emqug9j057e6k3uvdokbj13i@4ax.com...
>> This is a research question.
>>
>> I want to make a video which will be "invisble to kids" but
>> "visible to adults".
>>
>> Theory says this is possible because the PFF
>> (picture fusion frequency) of adults is around 15 frames/sec,
>> while the PFF of a 7 year old kid is only 10 frames/sec.
>>
>> OK, I can't use AVI, or MPEG or any kind of
>> "computer video" system because they are too slow
>> and tend to compress frame/rates unpreditably....
>> I have to use good old fashioned VHS tape and
>> play it on a VCR.
>>
>>
>> QUESTION:
>>
>> How can I most simply EDIT a VHS tape?
>>
>> What I want to do is take "any ole" average VHS
>> movie tape, and simply REPLACE some frames on
>> it, and then play it on my VCR.
>>
>> How can I most EASILY do this?
>>
>> Specifically, if I have a regular VHS video movie,
>> I wish REPLACE every 3rd,4th,5th,6th
>> frame of the video with "blank" frames
>> (say colored light gray)... so the tape will
>> look like this:
>>
>> 01|02|...|...|...|...|07|08|...|...|...|...|13|14|...|...|...|...|19|20|...|..|...|...|25|26|...|...|...|...|-------etc,etc,etc------>
>>
>> the |...| frames have been REPLACED in the original video
>> with these new "blank" (light gray) frames.
>>
>> HOW CAN I DO THIS.... what type of equipment, computers, VCR's
>> etc do I need to do this?
>>
>> Could a run of the mill commercial video lab alter a VHS tape
>> for me in this specific way?
>>
>> Thanks in advance, George Hammond

>I think that trying the "computer" way is worth a shot. You can write
>an AviSynth script that would blank the frames and then encode the
>result to mpeg. I think you can even force I frames to be at the
>significant frames.
>
>Erik.

[Hammond]
Erik.... thanks for responding. I am a physicist, who discovered
this idea, but I know beans about practical video stuff. This idea
has been widely discussed on the physics newsgroups, but none of them
know anything about practical video matters.
If it works, it may point the way to making "childproof X-rated
entertainment".... think about it... the amount of programming
effected on public t.v. would be enormous. Big bucks!
Of course the idea I'm proposing here is just a "simple experiment"
to try and find out something about the phenomenon.

The problem with AVI, MPEG and other "computer" video systems is
that most people (including me) are using old 200, or 400 mc CPU
computers with run of the mill graphics cards... and they are just too
slow.... they "compress" the frame rates unpredictably.... AVI only
runs at 12 frames/sec on my computer for instance. This will
OBLITERATE the effect which depends on running at
TRUE 30 FRAMES/SEC VIDEO SPEED (like t.v.) !

As I see it, the only way I can GUARANTEE that the video is actually
running at "true 30 frames/sec" speed is to do the experiment using
VHS video on a VCR.

CORRECT ME IF I'M WR0NG ABOUT THIS....!!

Isn't there some way to "edit" a vido on a computer, and then load it
on to a VHS tape?

You do see what the problem is, right? I have to be SURE the vido
that I produce is actually running at 30 frames/sec...!

George Hammond

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