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DVD-From Where and How



> 
> Howie Burch wrote:

> Hi everyone:

> I just viewed a DVD of a film called "Murder at 1600" and am curious
> as to who did the transfer and on what system. Also what compression
> system was used.

> If any one has the answers, I'd appreciate it.

> Howie Burch
> Nice Shoes
 
The film that you ask about is a Warner Bros. title and with the
building of the "on-lot" Video Operations Department most of the new    
current releases are transfered there.  Chris Cookson, Gary Morse, Paul 
Klamer and Jan Yarbrough and the rest of the crew have developed some   
unique methods of feature film transfers.
 
On inquiry this is what was done for this title.
 
The transfer was done on a Standard URSA Gold with no after market
add-ons to the telecine. Keith Shaw was the colorist.  Color Correction
and Telecine Editing was accomplished with a Pandora/Pogel equiped
with DCP that was fed from the 4:4:4 telecine outputs.  Secondaries
can be tweaked with both Cintel and DCP corrections.  This is where
all standard methods of operations end.

All telecine transfers are made at 625 lines.  The rooms are rarely
switched to 525 to make a domestic transfer.  In the case of an
anamorphic title the transfer is made with all 625 lines scanning the
squeezed film image. For purposes of viewing, the monitor is operated
in a vertical reduced scan mode for proper aspect ratio viewing. Noise
reduction is in the path after correction.  This is a Digital Vision
DVNR-1000 Box with the V-Zoom option. The V-Zoom processes the
vertically streached image to a standard letterbox picture.  This      
allows the telecine image (all 625 lines) to be used for the letterbox  
on-screen image.  This results in a much reduced amount of vertical    
alising. This output is a standard 625-25 frame letterbox tape.  This   
output is recorded to an Ampex DCT VTR, a tape format chosen for its    
robustness, interchange ability and 525/625 operation.  This recording  
is of course made at the normal 625 digital 4:2:2 standard.  (Warner    
Bros. Burbank is possibly the world's largest user of Ampex DCT  
machines and tape.)
 
These machines have what is now a standard Ampex feature (not an
option) that allows the VTR in the 625-25 Frame mode to be switched to  
playback at 625-24 (Twenty-Four) Frame.  This above 625/24 signal is    
fed to a Digital Vision (AFC) Anamorphic Format Converter unit.  This
was
developed  first for Warner Bros. but is now available for anyone to
purchase.
 
This AFC Unit was developed to do several things, depending on which
options were purchased. First it can take an Anamorphic Image and
center scan it or can pan-scan the image under computer control.  It
can also pass the image thru as the input, in this case an anamorphic
image.  Second and most important is it's ability to convert the 625
line/24 Frame signal to a 525 line/30 Frame signal.  In other words the
input signal was 24 Frame Progressive 625 lines and the output signal
is 525 line/30 Frame interlace with the 3rd field added just as the
digital frame store in the telecine does.  The vertical down
conversion or vertical filtering completly eliminates any last
artifacts of the telecine scanning vertical alising. This has been in
operation for over 3 years at WBVO.

This 525 line/30 Frame Interlace  tape now goes to the video
compression operation for 525 DVD Disks. A Toshiba DVD compression
system was used.  This is located at CVC (California Video Center-a
Warner Bros Division that is also the master control playback operation
for the WB-Warner Bros. TV network.)  The first operation that the
compression system does is discard this 3rd field that was added and
convert the signal to a 525 line/24 Frame Progressive video signal for
further processing. (Does this sound familiar? -- see above)  Of course
this signal is virtualy free of vertical artifacts and therefore
compresses better using less bits for a better DVD image. The DVD Disk
is made with all the other audio and other data added.  You buy or rent
this DVD disk for home use  The DVD home unit processes this 525/24
Frame Progressive signal to a 525/30 Frame Interlace signal for your
television display.

It adds the 3rd Field for every other film frame.....you have a
Digiscan/Telecine Framestore in your DVD player at home for less than
$500.  Who says that technology is not amazing?  DVD players have
4:2:0 Digital Signal processing internally which is up-converted to
4:2:2 to output to  composite, component Analog outputs or
S-Video(almost as Good) outputs to feed to your home display.

The audio and the timecode considerations are for another time.
 
I think I got a little off the subject of Howie's question.  But recent
discussion about HDTV and the viewing public's lack of seeing a decent
signal that they might even think is HDTV  got me carried away.
 
Bill Hogan    bhogan at sprocketdig.com           v.818-566-7700
Sprocket Digital       Burbank,CA              f.818-566-4477

---
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