Posted by Jan B on 04/15/06 17:52

On Sat, 15 Apr 2006 12:01:15 -0400, "~P~" <bmxtrix2005@cox.net> wrote:

>??? - You are saying that film isn't stored on DVD at 480/24i?
>
>This goes in direct contrast to what the link YOU provided states and which
>I quoted.
>
>I am not sure what the MPEG2 header says - or what that has to do with what
>is actually put on the disc itself - do you have any links or quotes from
>articles that has something to do with the header - since the very detailed
>page you linked to doesn't talk about the header at all. I can assure you
>that DVD players pull off the frames in a flagged sequence that is
>specifically called 3:2 pulldown or 2-3 pulldown (depending on where you
>read it). Either way, this work is performed by the DVD player processing.
>It is not encoded on the disc this way, it is just flagged as 24fps based
>material and requires 3:2 pulldown to be performed. A progressive scan
>player must go even further to recombined the frames with inverse telecine.
>None of that is on the DVD natively, but is flagged, then performed by the
>DVD player.

Now, I'm confused.
I thought this discussion was which of the two possible encoding
schemes is used for 24Hz material on a 60Hz DVD:

Call the 24Hz Film sequence
Frame 1
Frame 2
Frame 3

I see the two possibilites for DVD encoding:
1) No repeated frames are stored:
Frame 1 field 1
Frame 1 field 2
Frame 2 field 1
Frame 2 field 2
Frame 3 field 1
Frame 3 field 2

The DVD player creates 60Hz by duplication (a rather simple task) the
sequence below ...

2) The sequence to output is already encoded on the DVD:
Frame 1 field 1
Frame 1 field 2
Frame 1 field 1
Frame 2 field 2
Frame 2 field 1
Frame 3 field 2
Frame 3 field 1
Frame 3 field 2

So which one is the one beeing used?
(The next step would be to introduce the MPEG GOP:s in the example.)
/Jan

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