24p encode for progressive scan DVD players?

Jay-Hancock wrote on 10/3/2006, 12:16 PM
I know very little about DVD players... I searched the forum and didn't find the answers about this. So here goes.

I know that NTSC is always at 29.97fps (interlaced in the real NTSC world). But now we have digital televisions that can display 480p and 720p, etc. And almost all the newer DVD players have a "progressive scan" mode.

So what is the DVD player really doing to give you a 480p output to your digital television?

And finally, should we encode our MPG2 media for DVDA as progressive instead of interlaced to get best results on a DVD player, or does it even make any difference?

Comments

David Jimerson wrote on 10/3/2006, 2:28 PM
For interlaced material, it appears to do just a straight field blend, because interlace artifacts are often visible. Different players may do it differently, though.

For a 24p DVD, it's displaying the 24p material as is.

Some older players take the 24p material, add pulldown to make it 60i, then deinterlace it back to 24p, and then display it as 60p, adding 3:2 pulldown. Why? You got me.

If you've got 30p material, it has to be encoded as 60i, but if it's displayed with a straight field blend, you won't see any artifacting, because the fields being blended should be two halves of the same 30p frame.
Jay-Hancock wrote on 10/3/2006, 2:37 PM
Thanks for the great explanation, David!

Our DVDA software requires us to make our 24p DVDs as 23.976 with the 3:2 pulldown flag active. Thus our DVD isn't exactly 24p in what might be a purist point of view. Does this affect the player's behavior that you just described?
David Jimerson wrote on 10/3/2006, 2:58 PM
23.976p is indistinguishible from 24.00p. It's just an NTSC conforming issue.

The pulldown flags are only that -- instructions to the DVD player as to how to insert pulldown to display on a standard NTSC TV.
Jay-Hancock wrote on 10/3/2006, 3:46 PM
Maybe this is subjective, but would you recommend that we take our otherwise 60i projects and render them to 24p instead? (Using the 24p DVDA template in Vegas, of course..) I suppose this would be under the assumption that Vegas (at "Best" quality setting) will do a better job of deinterlacing than what the typical DVD player can do for output to a digital TV.

Thanks again for your good advice!!!
David Jimerson wrote on 10/3/2006, 8:48 PM
No, I wouldn't recommend that just for DVD. If you want your 60i footage to have the look of 24p, then convert it, but otherwise, render as 60i.

As for playing it on a progressive TV . . . it won't be that bad. Most players will let you play it as interlaced if you want. Now, the TV might deinterlace it . . . but try it. See how it looks.