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Re: 625 pitfalls



Dear Andy,

Transferring the same job at both 525 and 625 is actually more common a
practice than it sounds.  Some things to be aware of:

1. Ranks have separate vertical size adjustments for the two standards, so
the machine has to be set up both ways.  Size should be adjusted with respect
to the edges of blanking--not to some arbitrary reference mark (like a piece
of masking tape) on the monitor; remember those extra 100 lines in PAL!

2. The Rank's scan patch is bigger in PAL than it is in NTSC, which changes
the light.  This means that all your corrections will need some fine tweaking
when you change standards.  Don't plan on doing the job in one standard and
then running it on "autopilot" for the other transfer if you really want it
to come out the same.

3. Going from 24 FPS film to 25 FPS video means that the running time of the
PAL version will be approximately 4% shorter than the NTSC version.  (The
running time of a NTSC video transfer is 0.1% longer than if the film was
projected at a true 24 FPS, by the way).

4. The audio pitch will be 4% higher on the PAL transfer than on the original
material.  This is a noticeable difference which may be objectionable in some
cases, like music videos.  You might want to consider going through some sort
of pitch correction system (like a Lexicon).

5. You are correct in assuming that you will have problems syncing a DAT with
NTSC time code to PAL, since no current time code generators I'm aware of
will continue making 30 FPS time code while running at 25 FPS (they all
assume that if you're running at 25 FPS, you want 25 FPS time code).  

Unfortunately, you can't just clone the audio to another DAT with 25 FPS time
code since this won't create the requisite 4% increase in speed when matched
to the transfer.  If you have a DAT machine that has accurate variable speed
playback, you could try speeding up the tape 4% on the playback side and dub
it to another DAT that is locked to, and recording 25 FPS time code.  This
new DAT is then used for the PAL transfer.  No guarantees that it will work
perfectly, but you might get away with it, particularly if the transfer has a
lot of short takes.  

Another approach would be to have the syncing done after the transfer in an
audio layback suite. 

Good luck!

Christopher Bacon
DuArt Film & Video