From: katefans@chinet.chi.il.us (Chris'n'Vickie of Chicago)
Newsgroups: rec.video.production
Subject: Re: Mac Video Production Qs
Date: 20 Aug 92 07:30:57 GMT
Organization: Chinet - Public Access UNIX

In article <18AUG199223540368@cs.umass.edu> chait@cs.umass.edu (DAVID CHAIT) writes:
>I'm hoping that there are some people who can answer a few questions I have
>about going out to video from the Macintosh (although some questions don't
>necessarily involve the mac).
>
>1. What's the best price/quality/performance balance for going from the mac
>out frame-accurate to video (Beta, Hi-8, LD, ???; Diaquest, NuVista, sep.
>converter?)?

   Hi-8 appears to be the best value if you are only reading the spec
sheets, but it is an amazingly _fragile_ format, ill-suited to the rigors
of single-framing. Super-VHS is the lowest price/decent quality format
that is reasonably rugged. U-Matic SP is the minimun acceptable format
for output to broadcast, but for not _too_ much more one can pick up a
Sony 2800 Beta SP and have component recording, a rugged tape format,
and the ability to hand the finished product to any broadcaster or
post-production house. The likelyhood of you having the same laser
recorder as a post house is almost nil (if they have one at _all_.)

>2. Can someone explain 'fields' to me.  I understand that there are two
>interlaced fields per full screen refresh (vs. 1 for computer) of video,
>and that there are software packages that 'render fields' so that output
>to video looks smoother (i.e., frames have been field-interlaced throughout)?

   Basically you create your animation to be twice as long as the intended
running time, and (depending on the package) render all the frames half
height. When the frames are laid off to tape, two sequential frames are
combined into one final interlaced frame. The first frame (say number 30)
is used for the even numbered lines of the final frame, and the second
frame (number 31) is the odd lines. The result is far smoother looking
animation.

   Why render fields? Because most animation packages cannot produce
"motion blur" and the ones that can suffer a tremendous drag on render
speed. Whan every frame is in perfect blur-free focus, the 30-frame
per second rate of NTSC video is noticable. Look at real-time playback
of sports video (gymnastics for example) that is shot using the Sony
Super-Slo-Mo system. A shutter is used in front of the lens to "freeze"
each frame. It looks great in slow motion, but noticably flickers in
regular playback.

>3. Is there anyone out there who does dumps to video from the mac during
>non-primetime hours (thus not charging video room usage fees) and has a low
>cost to get a 3 min animation frame accurate out to tape/LD?

   There is a company here in Chicago that provides RenderMan rendering
and animation lay-off. The main reason for higher costs is that lay-offs
are _much_ harder on the video equipment than normal editing sessions.
There is no profit in charging _less_ for something that costs you _more_.


>
>Thanks all,
>Dave Chait
>

                                Chris Williams
                                   katefans@chinet.chi.il.us
Newsgroups: rec.video.production