[Tig] Reply to "Telecine output" from Steven Gladstone.

Peter Swinson peter_swinson
Fri Apr 19 14:45:20 BST 2002


[the following was scanned for marketing-speak by tig-admin]

Steven,

Your questions regarding 4:4:4, 4:2:2 and 8:8:8,  + is there a
way to get computer files at 4:4:4 RGB from the telecine.

Today's telecines, in general, can output either 4:4:4 or 4:2:2.
When feeding downstream color correctors such as da vinci and
Pandora the chosen output is 4:4:4 for the reasons you already
suggest. The term 8:8:8 as used by da vinci refers to their
internal processing. Basically think of it as upsampling the
color resolution. While this will not increase the resoution of
the basic scanned image it will allow some smoother color
transitions on fine image detail as internally the da vinci will
be working with twice as many pixels as exist in the 4:4:4 world.

The standard def signal is normally output from downstream color
correctors as 4:2:2 if it is to be recorded to tape or another
4:2:2 device. However if the transfer is to go through other
color resolution sensitive processes or further reiteritive color
correction then storing to DDR or other devices at 4:4:4 is
preferable. To the best of my knowledge 8:8:8  is not avaliable
as an input or output to the da vinci or other devices. No doubt
I will be corrected on this point.

Regarding your desire to put your Standard defintion images
through a computer based system while maintaining 4:4:4 there are
solutions. I believe there exist 4:4:4 SD input devices for PCs &
Macs, however unless you are physically coupled to the post
companies 4:4:4 routing it may be difficult to "grab" the video.

An alternative, certainly available  with Cintel C-Reality and
DSX  scanners, is a direct "NTSC" data transfer. Several
C-Reality's in the USA have data scanning facilities.  In this
mode the film is scanned at real time and the output is recorded
as 10 bit RGB  data DPX file standard to Cintel's Postware Raid
system. The image can be in linear or log color space. If ALL
color grading is to be performed after the transfer then log is
preferable. If the film is to have a full grade applied at the
telecine then choose linear space unless you want to get
embroiled in the never ending look up table and color space
conversion debate..

Once the transfer is complete and residing on the Data Raid disk,
it is a simple matter to copy the files to your own disk system
via ethernet or a suitable faster port.  Do not worry if DPX is
new to you, a freeware program called Xnview, available to
download from Xnview.com, will sequence or batch convert the DPX
files to TIF, BMP, or almost what ever you want.  The only caveat
is that the files will convert to 8 bit RGB rather than 10 bit,
however I guess your NLE system is 8 bit based. The conversion
will NOT resample the color or reduce color resolution and Xnview
is very fast at conversion, in my experience. You will then have
your desired files, 4:4:4 RGB NTSC as data.

I hope this helps

Peter Swinson.

Fully paid up member of Cintel







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