[Tig] Fwd: HDCAM SR 23.976 to PAL Downconvert Question

James Deluca James_Deluca at crestdigital.com
Thu Aug 7 07:40:04 BST 2008


Agustin Goya wrote:
Subject: [Tig] Fwd:  HDCAM SR 23.976 to PAL Downconvert Question

Hi Joe! Yes, it's very confusing.
I've been told that the specs are referred to the setting of the panasonic UFC-1800.
Maybe inside this equipment this settings are possible. I've downloaded the
User manual og UFC-1800 and the pull-down options are None, 2:2, and 3:2.
What I need to find now is what is the difference between None and 2:2 in
the UFC-1800 with 23.98 input and 25 output. I think that the 23.98 output
rate must be a mistake.

I don't have access to such device and think I'll never have in Argentina, so
maybe someone from the list could tell me it the 2:2 pulldown is the usual
1frame=2fields resulting in a 4.1% speed up.

I've also checked what greg fisher sent but i can achieve that from the DS
where the grading will be made. Once inside DS there's very easy to create a
new sequence with different framerate and do a frame to frame virtual
"Telecine" from the original sequence.
Thanks for your help,

I must have missed the preceeding message, but as I have both a Sony HDCAM-SR 
and a Panasonic UFC-1800P Universal Format Converter, I think I can set you 
straight.

Although both Sony and Panasonic offer 23.98P/24P SDI interfaces, both actually
record in segmented frame mode on tape due to the need to remain compatible 
with the 1080i modes of their machines design.

To make a PAL downconversion from a 23.98/24 master recording, the operator 
lies to the machine by setting it up to play in 25HZ mode (1080i/50, 1080P/25).
In machines fitted with downconversion capability, PAL should just fall out 
of the SD-SDI output.

If not so fitted, the 1080i/50 or 1080P/25 output is fed to the UFC-1800P set
for matching input, 625/25HZ output with 2:2 pulldown.
As for the BIG question about the difference between the 2:2 setting and NONE
I'm sorry, but I have never seen a difference when using NONE because all
video std def formats are interlaced and I suspect the unit would default to
2:2 even if it was set to 3:2. I haven't verified this though.

This link shows the table of permitted format conversions of the 
Panasonic UFC-1800P.  http://tinyurl.com/6h8jlv

James DeLuca
Crest Digital
Hollywood - Video Lab



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