[photo-3d] RE: Digital Video 3D

["Marcus Warrington" <marcusw@xxxxxxxxx>]

Original Message
   Date: Fri, 16 Mar 2001 11:01:12 -0800
   From: "John A. Rupkalvis" <stereoscope@xxxxxxxxxxxxx>

>> Some one said that a problem with the NuView is that it creates only
>> Field-Sequential encoded videos. True, but if you then capture this to
>> a digital stream for non-linear editing you can then extract these two
>> streams and convert to any other format you want..i.e. Under/Over,
>> Side-by-Side or Anaglyph. There are a number of plugins for Adobe Premier
>> to help achieve this.
>True.  But, each field has only half the information and resolution (half
>the number of scanning lines) of a full frame.  So your results will be of
a
>much lower quality going this route then going with a dual full frame full
>field system.

Yes that's true, F-S video by its very nature is only half the vertical
resolution. This is inevitable since its encoding two video streams into the
same bandwidth as a single 2D one.

The benefit of F-S video is its ability use available playback equipment
i.e. TV and VCR. I only mentioned the NuView because its available and
much cheaper than buying two digital camcorders and a PC to edit everything
on. If all you want is to shoot 3D video that you can play back on your VCR
at home then you can't really beat the NuView for the price. Like most
things in this world gradual increases in quality equate to larger and
larger increases in cost.

>> I think someone else mentioned that it should also be possible to create
>> anaglyph movies directly with the NuView by placing coloured gels on the
>> front of the device.
>This is a rather inefficient way to do this.  A simple beamsplitter device
>(like the NuView, but without the LCDs can be constructed using one front
>surface mirror and one dichroic filter.

Yes, I agree again. I only mentioned it because if you already have the
adapter then it might be an interesting thing to try without too much
effort or expense.

>> To get back to your particular question, you already have two cameras so
>> it should be possible to shoot both streams, load into the PC/Mac and
then
>This is a much better method than extracting streams from already
>multiplexed material, as there is no loss.   You have both full fields in
>both eye views, and if you want to, you can still multiplex later.

I agree (again), but for me it would have been a MUCH more expensive
route. If all your going to produce is anaglyph video on VHS tape then
I doubt that the higher quality (and cost) of 2 cameras and post editing
time is worth it compared to the lesser cost and quality  of the NuView.
If your aiming at more professional standards and have the money, then
two mini digital camcorders on a movable bar (for those hyper shots and
controlled zooms) seems like a really cool idea :)

>> I would question your intention of wanting to use Anaglyph. In my
>Correct.  MPEG2 works well with anaglyph as well as any other system where
>both fields are used continuously.

I don't think its so much an issue of using two fields, since I've made
successful anaglyph VCD's (MPEG1.. which doesn't support fields), its
more to do with the colour bandwidth that the digital compression allows.

>However the compression codec causes
>problems if you try to compress multiplexed material.

Yes that's true of MPEG1, since its not field based, and the compression
uses blocks of horizontal and vertical pixels, thereby fusing alternate
lines together. MPEG2 however DOES support interlaced fields and I have
successfully created field-sequential SVCD discs that play in full 3D
on my DVD player. SVCD's use the same MPEG2 compression as DVD's, the
difference is purely in disc layout and maximum bitrate. Once DVD writers
become more common place (and compatible) it should be possible to produce
home movies that have 2D,F-S 3D, anaglyph and any other format all on the
same disc.. just choose your preferred playback from the menu :)

ron labbe said:
>Some one said that a problem with the NuView is that it creates only
>>Field-Sequential encoded videos. True, but if you then capture this to
>>a digital stream for non-linear editing you can then extract these two
>>streams and convert to any other format you want..i.e. Under/Over,
>>Side-by-Side or Anaglyph. There are a number of plugins for Adobe Premier
>>to help achieve this.
>What plug-ins are these?

Filter Factory allows you write your own filters
Cult Effects, for After effects support mutiplexing streams into 3D
Michal Husak web page has some useful plugins written with Filter Factory
http://staff.vscht.cz/~husakm/stereopcvideo.html

> Does anybody know if Nu-View works for PAL?

YES, the adapter simply synchs to the video-out socket of your camcorder
(via an RCA fly lead), so it works with any (field based) video standard.
It even supports lefthand and righthand fitting by flicking an internal
switch to denote which way its mounted on the camera.

Marcus Warrington
MIS Computer Services (UK)



 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/