[Avid-L2] Re: A plea for Rec run TC on file based shoots, and to introduce 23.976 DF TC

Bouke,

Things are not quite as simple, and I would imagine that is why 23.976 is always NDF.
With 29.97fps, instead of :
30*60*60=108000 frames per hour

there are
29.97*60*60 = 107892 frames per hour or 108 frames less.

Now 108 = 54*2 = (60-6)*2 so if you drop 2 frames every minute except those divisible by 10 we get the right frame count.
(If we take the exact figure at 30*1000/1001 fps, there are 107892,108 frames per hour - i.e. we should also drop 1 frame every 10 hours, but few shots last that long....)

With 23,976fps instead of:
24*60*60=86400 frames per hour
there are
24*1000/1001*60*60=86313,69 frames per hour or 86,3 frames less.
which is tricky because: 1) it is not an integer so you'd need to correct and have hours that drop differently... and 2) difficult because even if we round the difference to 86 = 2*43 and 43 = 60-17 tricky...
Systems are possible but awkward. You could drop two frames every minute except for 17 of the 60 minutes in the hour
So, you could drop two frames every minute except every minute divisible by three but not minutes 0, 21 and 42... it gets complicated and it this isn't accurate. It'd also be a source of confusion as drop-frame is a pain as it is, without having multiple sorts of DF... (I live in France so fortunately I don't have to deal too much with it... :) )

So I don't think 23,976 DF is a good idea...

Best regards
Janusz

--
Janusz Baranek

> Thus to keep everything sync as possible, why not have 23.976 DF TC?
> Principle can be the same, forget 2 TC frames every minute except for the
> minutes dividable by ten.
> Or to make it more accurate (as i think it should be), just drop ONE tc
> frame every 1000 frames.
> (Remember the speed of 23.976 = 24 * 1000 / 1001
>
> Am i right?
>
>
> Bouke
>
> VideoToolShed
> van Oldenbarneveltstraat 33
> 6512 AS NIJMEGEN
> The Netherlands
> +31 24 3553311
> www.videotoolshed.com
> For large files:
> http://dropbox.yousendit.com/BoukeVahl998172
>

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