Where to start?
Let's look at the hardware...
Mac 660 and 840 AV models out of the box will allow you to capture
video. They will NOT capture full-frame, full motion video in 640x480
size. The best you can do is 12-15 frames (30 frames per second is full
motion) at the 320x240 size. In other words, quarter screen video at
slide show half speeds. The problem is processor speed. The 33 megahertz
68040 chips in the AVs don't cut it. I own a new Power PC 7500/100
and I can capture almost full motion, quarter frame out of the box
because I
have 100 megahertz of processor speed. Even these brand new, built for
AV PowerPCs come with DAV slots (Digital Audio Video). More on that
later...
Why, well even with much improved over the AV machines video
circutry, only the PowerPC
8500/120 will yield skipless video at 320x240 at 30 frames. It will
deliver "mostly" skipless video at full frame, full speed. The extra 20
megahertz over my machine makes a differnce. If you don't believe me.
read the article in Macuser or Macworld from earlier this year (I'm sorry
I don't know the date) and it will fully outline the shortcomings of the
AV machines-660 and 840- when it comes to filling the entire television
screen in NTSC with video.
Okay you ask, how do you get full motion??? You need to add another piece
of hardware. In the new Macs it goes in the DAV slot I mentioned
earlier. In older MACs, you need a NUBus video capture card. Why?
Video compression must NOT be done by processor speed (remember from
above). The card and its compression daughter card will take care of that
freeing your CPU to basically just sit there during digitizing. I ONLY
recommend the Radius VideoVision Studio board and Daughter card to be
used in a Quicktime compatible configuration. For dollar and performance,
it can't be beat. It will
soon be in PCI version for my new MAC, (Yea, right? Believe this when I
see it) and we use the NUBus version at Durango High School on
a Quadra 950 with a 2 gig disk array and 40 megs of RAM.
Oh, did I mention that digital video is also a function of hard
drive speed. Disk arrays, not hard disks, in SCSI fast and/or wide offer
the sustained throughput (at least 4 megs per second!!!)
you will need to spin full frame, full motion video. The SCSI Bus on the
840 AV is different than the 950 and will handle very high sustained
throughputs and 16 bit audio. We bought our 950 before the 840 was
introduced and have tried numerous time to trade with no success. Radius
now makes their own clone and card, but I have no experience with it,
and obviously their card will work on the NuBus PowerPC's.
The new Macs 7500 and 8500 already come ready
for SCSI fast inside in the box. In other words, they will spin data
even faster than the 660 or 840 AVs. Back to Radius. The card is about
$4000 and is the best of the Quicktime based cards for the money. We
started using it four years ago and it performs great with an appropriate
amount of Adobe Premiere tweeking. Yes, Dollar/performance better than the
Avid system.
Any scanner that will produce PICT images can be turned into video in
Premier with surprisingly good results. You can do this with a scanner
(we use a Microtek) and Premiere on your 660 no problem. You only need
to save the images at 75 dots per inch of reolution so 800 or 1200 dpi is
over kill. Why? Well the screen image on most computers in 72 dpi and
televsions in NTSC have less resolution than that--about 50+ dpi. This is
a neat multimedia activity when combined with sound in Premiere. No
digitzing video card or AV machine required!
When possible only use S-VHS video-you'll need the extra signal power
when digitizing and don't forget that you must also have a S-VHS vcr.
Both units together cost about $3000+.
A philosophical note about digital video. Premiere is powerful in the
right hands and you can do any and I do mean ANY effect in video using
Photoshop and Premiere and my students do it every day, but you are
competing with MTV and other splashy, glitzy video sources and your
students will tire quickly of 15 frames per second...I've seen this
problem at other places. AV machines at 15 frames may not yield the
expected level of performance. For example, as a teacher facilitating
students building multimedia presentations, 320x240 at 15-20 frames
is very acceptable. An AV machine would work fine for this example.
Before launching into digital video, call me, do your research and have
reasonable expectations based on your monetary and equipment availablility.
My Background: I am a five year high school teacher in digital video,
photography, digital photography, newspaper, yearbook and Language Arts.
I have and English and Communications undergrad and just finishing and
M.Ed at Colorado State University. I am on sabbatical for the 1995-1996
school year to earn my Master's Degree and Principal's certification.
Please write me, I HAVE BEEN THERE AND DONE THAT when it comes to
digital video.
I am also a computer consultant that would never charge a school for help
over the phone.
This may have been more than you needed to know, but let me know if you
have further questions...
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
K. Kevin Aten, M.Ed <<< My Three Rules for Life >>>
Colorado State University
1400 West Elizabeth #249 #1 "Build it and they will come..."
Fort Collins, Colorado 80521
Home and FAX 970*491*3162 #2 "It is always easier to apologize
Work 907*416*3581 than ask permission."
Work FAX 970*416*3580
#3 "The harder I work,
E-Mail katen@lamar.colostate.edu the luckier I get."
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -