Best way to get 29.97fps progressive video onto NTSC DVD

[Ste]

Hi, I have a few videos that I'd like to put onto an NTSC DVD. They're all 480x272p and 29.97fps. My goal is an anamorphic NTSC MPEG2 which, once authored and burned, will look good on all DVD playback equipment. My initial understanding is that for inherently progressive material to look its best on both progressive players and interlaced players, it needs to be 23.976p flagged for 2:3 pulldown.---I should also probably mention that I'm rescaling this video to 720x480p prior to encoding using AviSynth---

Now, I went through my first clip frame-by-frame and noticed that every 5th and 5th+1 frames were duplicates. So I added the Decimate() filter from DG's Decomb (or TDecimate() from TIVTC; both yielded same results) and I was able to get the clip to 23.976fps progressive. Only the duplicate frames were removed. It was easy from there, because I could just encode at 23.976p with flags for 2:3 pulldown. A progressive DVD player will detect the flags and reverse them. An interlaced player will detect the flags and perform the 2:3 pulldown (telecine) in realtime. So we're good both ways. Yay!

So I plugged in another similar clip into VirtualDub and went through frame-by-frame once more. This particular clip, however, contained no duplicate frames, and was still at 29.97fps progressive. I ran it through the Decimate() filter just for kicks. That got it down to 23.976fps, but it obviously removed frames that weren't duplicates. Not a fan of that. So my question is what's the best thing to do in a situation like this? Like I said earlier, my goal is to get this 29.97fps progressive video onto an NTSC DVD which will look good on both progressive output players and interlaced output players. Here are the options I know of right now:

1.) Do a straight framerate conversion to 23.976fps, but I would like to completely avoid having to screw with the audio to compensate for it. So I'd rather not do this.

2.) Use Decimate() to get to 23.976fps and just deal with the jumpyness due to the loss of perfectly usable frames.

3.) Encode the MPEG2 as 29.97fps Interlaced. My understanding is that this will look okay on interlaced players, but progressive players will have to attempt video deinterlacing on this material. As we all know, a lot of the cheaper players don't do this very well.

4.) Encode the MPEG2 as 29.97fps Progressive (or 'non-interlace' in TMPGEnc). I believe I read somewhere that this will look fine on a progressive player, but won't look so good on interlaced players. I could be wrong since that's a vague memory.

So what do you guys think? Are there any other solutions that I'm missing? Please let me know. I'd appreciate any type of help. Thanks.

[Soopafresh]

#4 Will work fine. It'll look nice even on an interlaced TV set.

[manono]

My initial understanding is that for inherently progressive material to look its best on both progressive players and interlaced players, it needs to be 23.976p flagged for 2:3 pulldown

Not if it's true 29.97fps, either progressive or interlaced.

Now, I went through my first clip frame-by-frame and noticed that every 5th and 5th+1 frames were duplicates.

If you're saying that in every 6 frame sequence there were 2 duplicate frames, what you did was dead wrong and will result in jerky playback. If in every 5 frame sequence there were 2 dupe frames, then Decimate() is correct.

Not a fan of that. So my question is what's the best thing to do in a situation like this?

Even if the source is progressive 29.97fps, it's almost always encoded as interlaced 29.97fps. As you say, though, inferior players might choose to deinterlace it and degrade it. What do you care, though, as long as you have a decent player yourself?

I could be wrong since that's a vague memory.

You're wrong.

[DVWannaB]

Hmmm.....this is a new one on me. never heard of a 4+2 pattern before. sounds to me like Decimate() should work with 2:3 Pulldown to make it 23.97 progressive. One fear I have though, is jerky playback. I have done this successfully with 3+2 pattern, but 4+2 I have not experienced. The safest bet I imagine is encode as straight MPEG2 29.97 Interlace. You would have to have a pretty bad DVD player to not play this properly. Let us kow how it goes.

[manono]

You just use Decimate(6) to make it 24.975fps. Leaving it 29.97fps also has it play jerky. Call it 2:3:2:2:3 Pulldown. It or something similar is sometimes used to convert 25fps PAL sources for NTSC.

[Ste]

Now, I went through my first clip frame-by-frame and noticed that every 5th and 5th+1 frames were duplicates.

If you're saying that in every 6 frame sequence there were 2 duplicate frames, what you did was dead wrong and will result in jerky playback. If in every 5 frame sequence there were 2 dupe frames, then Decimate() is correct.

Sorry I wasn't clear on this. What I meant was that every 5th and 5th+1 frames were duplicates of each other. I'll just explain what I saw. While looking in VirtualDub, frames 5 & 6 are duplicates of each other, 10 & 11, 15 & 16, 20 & 21, etc. Now, I did the math on the results and only the duplicate frames were removed. This was also verified visually. No jerkyness at all.

Not a fan of that. So my question is what's the best thing to do in a situation like this?

Even if the source is progressive 29.97fps, it's almost always encoded as interlaced 29.97fps. As you say, though, inferior players might choose to deinterlace it and degrade it. What do you care, though, as long as you have a decent player yourself?

I'm not the only one that's going to watch it. But I think what you're trying to say is that encoding as 29.97fps interlaced is the official thing to do. I'm assuming when this is done every 2 interlaced fields represent the same frame. An interlaced player displays these fields. A good progressive player will detect there is no motion between fields and reconstruct (by weaving the entire fields) the original frame.

4.) Encode the MPEG2 as 29.97fps Progressive (or 'non-interlace' in TMPGEnc). I believe I read somewhere that this will look fine on a progressive player, but won't look so good on interlaced players. I could be wrong since that's a vague memory.

You're wrong.

So what you're saying is that both #3 & #4 will look fine both ways? Soopafresh also agrees with number 4. So I guess another question I have is what does an interlaced output DVD player do with an MPEG2 encoded at 29.97fps progressive?

Thanks for all the responses so far. You guys are awesome.

[manono]

Sorry I wasn't clear on this.

No, you weren't. So you just have standard stuff that a Decimate() will take care of.

...encoding as 29.97fps interlaced is the official thing to do.

Yes, retail DVDs almost always do it. I often encode progressive 29.97fps stuff as progressive and it plays fine. Either way it's no problem for a player outputting 480i to an interlaced display. Where the problem might arise is for a progressive scan player outputting to a progressive display. The lousy flag-reading players might choose to deinterlace it, while a better cadence-reading player will pass it through as-is. If the deinterlacer is good enough (and sometimes it isn't), you might not even be able to tell the difference.

So what you're saying is that both #3 & #4 will look fine both ways?

Yeah, pretty much. What I was disagreeing with was the part about progressively encoded 29.97fps looking bad on interlaced displays. 480i outputs just the fields. In the case of progressive 29.97fps material, each pair of fields comes from the same point in time. Encoded as interlaced or as progressive, the 480i output is the same.