Rendering in 24p to Burn to DVD

[kmcgrath]

I shot in 24p advanced, edited, and want to create a dvd with native 24p using DVDA. My understanding from reading the Sony whitepaper is that the dvd player will detect flags on the disk when it is burned with native 24p and then insert 2-3 pulldown for NTSC viewing. Is this correct so far?

Anyway, when I go to render my 24p video in Vegas, I select the default "dvd architect 24p NTSC video stream" (as noted in Sony whitepaper), but in the custom template settings (in rendering setup) on the "video" tab I notice a pulldown menu where I can select a frame rate of "23.976 + 2-3 pulldown" or "23.976" (as well as several others). Can someone explain the difference between these two? I would guess that the former setting would insert the 2-3 pulldown during rendering and the latter would result in native 24p rendering (whereby the dvd player would then insert the pulldown), but can anyone confirm this for sure?

Is there any way to determine with certainty once a dvd is burned that it contains native 24p instead of 24p with 2-3 pulldown?

Thanks much!! This site has been fantastic to a newcome like myself.

[braw]

I noticed that with the 2-3 insert it adds frames causing a wierd strobe. I now always change it to 23.976 for output in the template. I noticed it when i advanced one frame at a time on a regular dvd, it was one new frame of info, with the pulldown insert. Outputting at 23.976 gave me the same as a regular DVD.

Hope that helps.

[scharky]

Gotta dissagree with you Braw. using "23.976+2:3 pulldown" does not add frames, it is adding flags for the DVD player to later acknowledge. The way to test this would be to render out the same file twice, once with 29.976fps and one with 23.976+2:3 pulldown. You will see that the 23.976fps footage will be smaller. Now, when you go to make your DVD, if those flags aren't there, the footage will not be up to the DVD spec, making your DVD program (DVD Architect) re render that footage. You don't want this to happen. Trust the template, it works perfectly.

[David Jimerson]

Well . . .

A little more to the point, it gives DVD-A the flags it needs to create the 24p DVD.

But yes; it works. *The templates are there for a reason. Use them.

[kmcgrath]

OK, I think I am beginning to understand. Let me recap: you go to render and select the "dvd architect 24p NTSC video stream" template. Now, you can go to the custom tab in this template, and under "frame rate" it lists the DEFAULT as "23.976+2:3 pulldown". That is what Scharky is saying inserts the flags so that the dvd player can insert flags for pulldown insertion for NTSC view, BUT STILL PUTS native 24P on the dvd. Correct so far? Now, what if you selected "23.976" under the "frame rate" instead of "23.976+2:3 pulldown"? Does this just mean the flags are not inserted for the dvd player to insert the pulldown (in which case it would not play properly thru an NTSC device but would, for example, play OK on your computer monitor (a progressive device)??

[David Jimerson]

It means DVD-A will re-render the project and take more time, basically. It will still play on a TV.

I believe the option is given for 23.976 with no pulldown for use with other authoring apps.

Just stick with the defaults. You'll be fine.

[kmcgrath]

OK, gotcha. But I still think labelling the framerate as "23.976+2:3 pulldown" when the framerate is 24p (with no pulldown) is a bit confusing to the uninitiated like myself.

[braw]

Gotta dissagree with you Braw. using "23.976+2:3 pulldown" does not add frames, it is adding flags for the DVD player to later acknowledge. The way to test this would be to render out the same file twice, once with 29.976fps and one with 23.976+2:3 pulldown. You will see that the 23.976fps footage will be smaller. Now, when you go to make your DVD, if those flags aren't there, the footage will not be up to the DVD spec, making your DVD program (DVD Architect) re render that footage. You don't want this to happen. Trust the template, it works perfectly.


You're correct scharky, my terminology was wrong. It does add flags for the DVD player to insert frames on the fly if needed.

What I have noticed, is that Hollywood style DVD's when advanced a frame at a time on my player, display an entire new frame of info with no stutter, but with the 2+3 pulldown, it adds a stuttery frame advance that goes a frame ahead and falls back. Now when I just do 23.976 to an MPEG file, DVD Architect never re-renders anything when I do it this way. The result is a solid new frame of info when stepped ahead.

I'm not entirely educated on all the technical intricacies involved, I just know from raw experimentation. On a DVD that has extras shot in 29.97, it stutters but the main feature at 23.976 advances smoothly. So for myself, I would rather output at 23.976 to optimize the look. It's the whole reason I want 24p, so why alter the cadence when major DVD releases don't?

[scharky]

Hmmm, I'll have to try it again. I remember the last time I did it, mpeg 24p no pulldown, Architect didn't want to recognize it, and it made me re-encode. As far as the frame by frame playback, I have never noticed what you have described. Are you talking about a computer DVD player or a set top? What do you mean by it falls back? When you step through do you get 24 frames before the counter goes to the next second. I'll have to try some tests with what you are talking about and see what happens.

[braw]

Hmmm, I'll have to try it again. I remember the last time I did it, mpeg 24p no pulldown, Architect didn't want to recognize it, and it made me re-encode. As far as the frame by frame playback, I have never noticed what you have described. Are you talking about a computer DVD player or a set top? What do you mean by it falls back? When you step through do you get 24 frames before the counter goes to the next second. I'll have to try some tests with what you are talking about and see what happens.

Well, I use the template for DVD Architect but change the framerate to 23.976. On my DVD player for my tv (and on a friends), when i step ahead a frame at a time, on a Hollywood style DVD, each frame is a new image and solid. When I use the 2+3 insert deal, it steps ahead sometimes a whole frame, and then will go to the next frame and fall back to the previous one. I think it's the flags. Where it has to double up or tripple up frames for 29.97. It's possible that it's a setting on my DVD player, but it reads movies that are 24p correctly. My impression was that the 2+3 insert is to bump it back to standard NTSC, which is silly to shoot 24, and go back to 30.

I have just never noticed any professionally encoded DVD that is a film transfer do that. Without the 2+3 flag, my DVD's never do that either.

[kmcgrath]

It sounds to me like you guys are saying to use the "23.976 frame" rate in Vegas (when getting ready to render) rather than the default "23.976 + 2, 3 pulldown". The only thing that concerns me is that everything I'm hearing from the previous response on this site is to "go with the defaults". But selecting 23.976 frame rate is not the dafault setting. Who is right?

[braw]

It sounds to me like you guys are saying to use the "23.976 frame" rate in Vegas (when getting ready to render) rather than the default "23.976 + 2, 3 pulldown". The only thing that concerns me is that everything I'm hearing from the previous response on this site is to "go with the defaults". But selecting 23.976 frame rate is not the dafault setting. Who is right?

I can't say who's right since my experience is limited. However, from the tests I have done, I always select the DVD Architect profile, and change the frame rate to 23.976. If you have the ability to try rendering a small section at both settings and try it on your DVD player, I would recommend it. Step through the frames one at a time and see if there's a difference. I saw one, and decided since the frame advance acted precisely the same as my store bought DVD's, I use what I mentioned.

There's quite a few variables here so a third experiment would only help us all out.

[kmcgrath]

From your experimental results, I agree with you. It sounds like there is a difference in what is put down on the dvd depending on whether 23.976 or 23.976 with 2-3 pulldown is selected. Sounds to me like the former setting puts down native 24p on the dvd, and the latter inserts pulldown on the dvd (although maybe it is simply telling the dvd player to insert pulldown). One thing we know for sure it that when viewing on a TV. pulldown is inserted either way (by the dvd player or when being rendered by Vegas). Maybe the way to check this out is to try it both ways, and then view on a progressive device. I think progressive device would show 24 frames per second (if native 24p on dvd), but would show 30 frames per second (if pulldown was inserted onto the dvd by Vegas). Any thoughts out there on this "test".

[David Jimerson]

As I said above, DVD-Architect removes the pulldown from the file exported from Vegas using the default settings. All you're doing by going with the file with no pulldown is making DVD-A re-render the entire video file.

[kmcgrath]

There is a "Preferences" box in DVDA where you can choose to allow pulldown removal when opening a 24P file (that may have the 2-3 pulldown, depending on whether it is added in Vegas, as discussed previously). So if the preferences box is checked in DVDA, wouldn't DVDA have to re render in that case, since it has removed the pulldown coming from the Vegas file? And if the video file is sent over from Vegas without the pulldown (i.e., the "23.976" box is checked in Vegas), wouldn't DVDA be smart enuf to figure out that the pulldown was not there and then not have to re render the whole thing?

[David Jimerson]

No and no. But go ahead and try it.

[braw]

As I said above, DVD-Architect removes the pulldown from the file exported from Vegas using the default settings. All you're doing by going with the file with no pulldown is making DVD-A re-render the entire video file.


You're correct. I just ran a test and had it reversed. When testing, I tried without the 2:3 pulldown and it interpretted it wrong in DVD-A. Just use the default like suggested. My appologies for confusing anyone...especially myself. :-/

[kmcgrath]

I just transferred a file from Vegas to DVDA (with the 23.976 + 2-3 pulldown checked in
Vegas), and burned a dvd. No re-rendering was done in DVDA, which is what David and Braw are saying. So, just to put the last anal retentive nail in my coffin, how can I prove to myself that what is burned onto the dvd is native 24P and not 23.976 + 2-3 pulldown?

[braw]

I just transferred a file from Vegas to DVDA (with the 23.976 + 2-3 pulldown checked in
Vegas), and burned a dvd. No re-rendering was done in DVDA, which is what David and Braw are saying. So, just to put the last anal retentive nail in my coffin, how can I prove to myself that what is burned onto the dvd is native 24P and not 23.976 + 2-3 pulldown?

After debating this, I did render the same scene out at 23.976 and at 23.976 with 2:3 and compared them on my tv. The default template is correct in the sense that it acts like a film tranfer when stepping through the frames. You can try it yourself if you have doubts. Also, open the mpeg in Vegas and in the media pool it should say that the frame rate is 23.976.

So stay with the 23.976 with 2:3.

[kmcgrath]

How about this as a test to see if native 24p in burned on the dvd? Make a video of a clock with a visible second hand or a stopwatch. When you play back on a progressive device (computer monitor), and step thru each frame you should count 24 frames for each second that has elapsed on stopwatch. If you play back on a tv (60i device), you should count 30 frames for each second elapsed on stopwatch. Does this sound like a definative test for native 24p on the dvd?