You did not remove the pulldown if you shot 24p. The pulldown never existed. But in order for a 24p video to play on a standard NTSC 29.97 display, pulldown has to be added. The flag tells the DVD player to add the pulldown.

Dave T2

Wow. Thank you both... I never understood this until now. So that makes sense that I'd render using the DVDA template that states 23.976 + 2-3 pulldown for 24p footage. That seems as if it would do what you're saying... adding the pulldown/flags.

What would define a "more advanced player" that can play true 24p... what specifications would I be looking for?

I think you'd get your highest quality by NOT rendering to 23.976 + 2-3 pulldown.

Render into a 23.976 stream.

The other options will add pulldown (either the 2-3 type or 2-3-3-2 type) and result in an interlaced 29.97 stream. That will be lower quality since it won't compress as well.

2- As I understand it, pulldown flags are metadata that indicate the type of the pulldown and the cadence for a 29.97 stream.

So I thought I understood this but now I don't. If I utilize a 24p (23.976) process from the Sony V1U and Canon HV20 all the way from the camera to Vegas, then I want to have 24p on the DVD. To have a 24p DVD, in the Vegas template "DVD Architect 24p NTSC Widescreen video stream," it seems I'd have to go to the Video tab, and under frame rate change from the default "23.976 + 2-3 pulldown" to the "23.976" option. But that seems contrary to what John and Dave were saying above... unless they were thinking I wanted to watch the 24p DVD in 29.97 stream.

Also, the Vegas DVDA template default for a 23.976 DVD INCLUDES the pulldown. If I change from the default, and then bring it into DVDA, it re-renders the footage. If you look at the Vegas and DVDA Help menu for preparing NTSC MPEG files for a DVD, it'll tell you that you either have to prepare as 29.97 OR 23.976 + pulldown.

"You did not remove the pulldown if you shot 24p. The pulldown never existed. "

This isn't true with the canon HV20. The pulldown IS added by the cam.

Not that I'm any guru on things 24p, the only cameras I've got that really shoots that sure as heck doesn't add pulldown but then again they don't write to tape.

Pulldown is typically added when writing to tape because very few VCRs can read 23.97. So by adding pulldown the VCR is none the wiser. Simple, elegant system. Canon do make a couple of cameras that don't add pulldown and the result is a nightmare that even the local Canon people get friggin WRONG. They told a local post house to get a Sony A1, that'd play the friggin Canon 24F tape for sure, yish!

Now after you've captured said tape with pulldown you remove the pulldown to get back your discrete 24 frames per second. You edit that. Then maybe put the pulldown back so you can do a print to tape because unless you're uber wealthy and can afford a Sony CIneAlta VCR your VCR will not have a clue what to do with 24p.

Reason to remove the pulldown during editing is so all your FXs, dissolves etc are rendered as 24p. If you don't remove the pulldown then you have a dogs breakfast of mixed 24p and 60i which could confuse a display device trying to workout what is going on, to say nothing of looking a tad wierd. Not that anything will blow up if you do this, it seems quite a lot of film originated TV shows in the USA are done this way. I guess the viewing public has got better things to do than watch dissolves frame by frame :)

Reason I get a bit upset about editing P on an interlaced T/L is you can make things really messy if you ever want to convert between NTSC and PAL. It should be a piece of cake for film or 24p video but if you've got interlaced FXs and motion graphics it's a bit of a mess or maybe I wasn't able to find the magic formula.

Bob.

ps. What you need if you do have a Canon 24f tape is a Canon A1.

I think I'm starting to figure this out. I tape with the V1U and HV20 in 24p mode, and then Cineform removes the pulldown. I edit in 24p as Bob stated above. If I render out to a computer file (wmv, mp4, etc.), I watch it in 24p (well, 23.976).

Putting it on standardDVD and viewing is the issue. Anyone correct me if I'm wrong here: I render via DVDA template, which renders in 23.976 and adds the pulldown back in, because a standard NTSC TV can only display 60i. Wikipedia http://en.wikipedia.org/wiki/24pstates[/link]: "With NTSC equipment, it is impossible to display a 24p signal directly as the monitors only support the 60i framerate. Hence, pulldown must be added to the 24p material to be displayed. Most editing systems will either add 3:2 pulldown or 2:2:2:4 pulldown.... DVDs, however, are capable of storing the native 24p frames. Every Hollywood movie is laid to disc as a 24p (actually 23.976p – see below) stream. With a progressive-scan DVD player and a progressive display, such as an HDTV, only the progressive frames are displayed and there is no conversion to an interlaced format – eliminating the appearance of any interlace or de-interlacing artifacts. When displayed on a standard NTSC TV (which only display 60i) the DVD player will add 3:2 pulldown to the signal."

Here's the issue: To make DVD's that people can watch on a standard TV, the DVDA template addes pulldown back in. But how would the DVD player know whether or not the pulldown should be added in or not? If viewed with a regular DVD player but via an HDTV, would it look 24p? If viewed on a standard TV, would it look 24p or would adding the pulldown back in make it look 29.97?

You hit the nail on the head.
NTSC is a STANDARD that was developed many years ago (late 50's, and the early 60's included the color burst).

That standard does NOT include progressive display. As a result it's quite impossible to create a "NTSC" dvd with progressive scan. Any "NTSC" dvd will be interlaced... other wise it can't be recognized as a "NTSC" dvd.

Now you're really strecthing my knowledge.
I THINK the answer is that the DVD players normally add the pulldown to the output for the 60i TVs.
SOME DVD players can be told not to add the pulldown. You'd only use that if you have a display capable of displaying 24p.

Also some HDTVs attempt to analyse the actual video and workout if the material could / should have pulldown removed. Now you can see how things can get a bit messy if you edit 24p on a 60i T/L. A display device may analyse the footage and start removing pulldown and all would be going nicely until it hits a dissolve.

Some player software such as VLC also permit you to tell it what to do. If you looks around some of the AV forums you'll find lots of info about all this and how things go wrong.

Not to worry though, soon my long held dream will come true and we'll all be shooting and watching 50/60p. This technolgy for some obscure reason seems to have given the TLA of "3G".

Bob.

"Here's the issue: To make DVD's that people can watch on a standard TV, the DVDA template addes pulldown back in. But how would the DVD player know whether or not the pulldown should be added in or not? If viewed with a regular DVD player but via an HDTV, would it look 24p? If viewed on a standard TV, would it look 24p or would adding the pulldown back in make it look 29.97?"

As far as I understand it, a STANDARD dvd player is built for STANDARD ntsc disks and pulldown is NOT added because it should already be included in a "NTSC" disk..... just as the canon HV20 puts out a standard ntsc signal when outputting to a tv (even with a 24p shot).

The more advanced and modern progressive scan dvd players looks for "flags" in order to tell it what kind of disk is being played.

I should also add that no matter what kind of dvd player you have... you will get nothing but a "NTSC" signal out of the Svid and composite outputs. On the newer players you will have component and HDMI outputs which are usually switchable between progressive and interlaced ("NTSC "signal)

There WAS a bit of a transition period with the Svid connection. If you matched up the tv CAREFULLY with the proper dvd player then you could get progressive scan through Svid. My older JVC dvd player is capable of progressive scan though the Svid, but the manual states that it has to be connected to a JVC tv that recognizes the rather unique signal that is put out.

"As far as I understand it, a STANDARD dvd player is built for STANDARD ntsc disks and pulldown is NOT added because it should already be included in a "NTSC" disk....."

A DVD can, and a lot of times does, include 24 fps video. The DVD player/standard will add pulldown when needed to play back correctly. This is another way that commercial movies can look good, there are not as many frames to encode at 24fps. There is a FLAG included in the MPEG file that instructs the DVD player to add pulldown.

Dave T2

I am pretty sure that ALL NTSC DVD players can handle a disk with 23.976 progressive video with the pulldown flag. AFIK, this is how ALL Hollywood movies are encoded and is one of several reasons why they look so good, even when encoded at very low data rates (if you "rip" a Hollywood movie and look at the average bps, it is very low).

The Canon HV20 adds pulldown to the video so that it can be attached directly to an old-fashioned TV set for playback, since a regular TV must see 29.97 interlaced and can't play 29.976 or 24 progressive. These extra fields must be removed which is actually an extremely tricky and error-prone process. I have spent a huge amount of time on this particular problem because I use a variation of it in the film capture system I invented a few years ago. If you go to the Canon forums, you will find all sorts of strange and wonderful recipes for removing pulldown because people don't want to spend lots of money for Cineform.

So, from your last post, it sounds like you have correctly figured it all out. Time to start editing and creating DVDs!

"A DVD can, and a lot of times does, include 24 fps video. "

I never said it couldn't.... It's just no longer seen as a "NTSC" dvd. The Vegas template marked NTSC dvd for a reason, and that is that it adheres to a set standard.... which is interlaced. You simply CAN NOT create a progressive "NTSC" dvd.... there is no such thing.

You simply CAN NOT create a progressive "NTSC" dvd.... there is no such thing.

I'm not sure I understand. Maybe it's just a matter of semantics. Clearly I can create a 24 fps progressive DVD that plays on NTSC DVD players. The DVD spec specifically provides for this, and as stated directly in the spec, this is how almost all movies are encoded:

"the progressive_frame flag of the MPEG-2 video stream ...indicates that a picture contains interlaced or progressive vertically correlated information. Almost all MPEG-2 coded movies consist exclusively of progressive frames. "

This is directly from the MPEG spec at mpeg.org.

ref: http://www.mpeg.org/MPEG/DVD/Book_B/Letterbox.html

Blink3times,

I cannot find specifics yet on what is considered an NTSC DVD, but I was actually responding to the quote that I lifed from your post. A STANDARD DVD Player will play a 24fps DVD. Whether that DVD is considered standard NTSC, I don't know.

Dave T2

edit: Found it, there is a DVD NTSC FILM standard.

http://myfreebsd.homeunix.net/hints_n_kinks/dvdstuff.html

You can send a progressive image as if it were an interlaced image. In the DVD format, setting the progressive flag does change how the chroma is encoded... progressive 4:2:0 is higher quality than interlaced 4:2:0 (but doesn't work with interlaced footage). There might be a difference in how the motion compensation/estimation is handled... but I don't know.

2- The 24p default template for the mpeg2 encoder in Vegas does seem to render a 23.976 stream, and the file size is smaller than 29.97... so I think you'd be fine to run with it.

(I'm not sure what the different frame rate options do.)

Phenomenal responses... thank you all very much. I'm on my way to "start editing and creating DVD's" before I get admonished again by Johnmeyer! Actually, I've completed taping/editing a two hour concert in 24p HDV via 3 V1U's and an HV20 in the rear, and it came out very well... I was just ready to render to HD file format and also to DVD. I hadn't put footage on a DVD since going to HDV/24p with the V1U's (most people I've done work for since upgrading to HDV cameras wanted the HD quality via computer files), so I wasn't sure how to use a DVDA template while keeping the 24p element.

The 24p default template for the mpeg2 encoder in Vegas does seem to render a 23.976 stream, and the file size is smaller than 29.97...

This shouldn't happen. The ONLY thing that affects the size of an MPEG-2 file is the average bitrate. You can encode at 1 fps or 100 fps, and if the average bitrate is 6,000,000, the files will be the same size.

One thing that confuses this a little is that the Vegas single-pass VBR encoder does a lousy job of estimating, so the file sizes are never consistent. However, if you use CBR or 2-pass VBR using the MainConcept MPEG-2 encoder built into Vegas, you will get very predictable results, and the file size will be exactly the same regardless of the framerate.

Interesting topic. Will DVDA actually author a 24p DVD?
I searched the Help and it really doesn't address this issue.

Another problem I struck with Vegas and the V1P is the camera records 25PsF with the correct flags which Vegas does see. Although you can write 25PsF back to tape we could never find a way to get the flag set correctly.

Bob.

The ONLY thing that affects the size of an MPEG-2 file is the average bitrate.
In this case, I believe I was using the VBR setting (though I think CBR would give similar results anyways).

One render is from 29.97fps 'interlaced' material. For all intents and purposes, the MPEG2 encoder might think that the material is interlaced since it's unsafe to assume that it's progressive.
*A very smart encoder would switch between progressive and interlaced encoding (as applying progressive techniques may work better)... though the Main Concept encoder doesn't seem to do this.

The second render is from 23.976fps progressive material. This is less data than the 29.97fps material and the encoder can also assume that the material is progressive and use progressive encoding techniques.

2- You can try it for yourself and see that the file sizes are different.

Although you can write 25PsF back to tape we could never find a way to get the flag set correctly.
Possibly because Vegas is stripping the metadata as it goes back onto tape?

I don't think Vegas is designed to copy metadata back in... and things would get more complicated if you have multiple video tracks (which metadata would Vegas grab in that case?).

"Possibly because Vegas is stripping the metadata as it goes back onto tape?"

I don't see the connection. The flags are set by the mpeg-2 encoder.
As I recall it we could capture a tape from the camera and write it back to tape, flag intact. What we couldn't do was encode a file out of Vegas and do a PTT and then capture that back and have Vegas see it as "P".
Confused yet?

I think you can encode a "P" m2t file out of Vegas and Vegas will read that file as "P". I suspect there's another flag that says PsF.

Bob.