[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[TIG] 4x4 recording on a D1 or tw




16/05/1996   1:44 PM    4x4 recording on a D1 or two.
Martin Parsons                   >>>                 The Mill   40/41 Great...

All,

I've looked at the option of recording a 4:4:4:4 serial digital video signal
onto a D1 here at The Mill and have come to the following conclusions:

Using a Sony DVPC-4224 Digital Signal Processor attached to a Sony DVR-2000
VTR with the appropriate upgrades, does definitely work through using some
**video compression** techniques.
I assumed that this would be along the lines of 2:1 compression although I
have heard various opinions that the ratio might be higher.

The inescapable fact is, however, that you will only record 8 bits (not the 10
bits that seem to come out of most 4x4 gear) which inevitably means loss of
information and, unless properly truncated, will cause minor hue errors.

What happens if the DVPC-4224 converter box dies ? 
In normal 4:2:2 D1 recording, if a D1 VTR goes down, the tape is simply put
into another D1 machine (assuming one is free !!) and the job continues.
If the DVPC-4224 dies, the tape is then *unreadable* by ANY machine, unless
another DVPC-4224 is available. 
If the D1 attached to the DVPC-4224 dies, the DVPC-4224 can be moved to
another D1 - but then did that D1 get the correct upgrade as well?
Simple things - but easily overlooked.

The 4:4:4:4 signal can be recorded onto two Sony 2000 series D1s but again is
limited by the 8 bit issue.
Also, is it economically and operationally viable to tie up two D1s on a job??

My conclusion to all this was to wait for a more elegant solution to come
along.

One thing I'd like to add. 
Bob Festa, in introducing this subject, wrote 
"I understand graphics devices like Flames can take 4:4:4 input from non
real-time disk recorders......"
The Flame can take a 4:4:4 input in *REAL* time via the Sirius Card.
At The Mill we telecine a 4:4:4 image from the Ursa Gold, through the BTS
noise reducer with "Booster Box", in and out of the Pandora DCP and directly
into the Flame all in real time by splitting the video into two streams, 4:2:2
and 0:2:2.

If anyone does have an elegant solution to storing 10bit 4:4:4:4 video then
please let me know.

Martin Parsons
Senior Engineer
The Mill