24p -> DVD ... NO Pulldown

[scottrwn98]

I have a 23.976 project in my AVID timeline that I export Quicktime Reference, that I then encode with ProCoder and it adds that NASTY 3:2 pulldown for broadcast display.

I know something out there exists that you can take a QuickTime Reference, 24fps video and encode it to a M2V or MPEG2 at "24fps" so when burned to a DVD, it will be 24i (like all movies we buy on DVD)...Because I know the DVD player has to "pulldown" the DVD to display on a television ...

Does this exist? or is this something that is Hardware based at a Major Motion Picture studio?

[manono]

Hi-

I know nothing about Procoder, but you're misinformed about at least one thing:

...so when burned to a DVD, it will be 24i (like all movies we buy on DVD)..

Most, but by no means all, movies are stored on the DVD at 24fps progressive (or 24p, using your terminology). Ordinarily the 3:2 pulldown is applied at that point (aka soft telecine) following the flagging in the video stream to output 29.97fps interlaced (or 30i, if you will). As far as I know, there's no such thing as 24i.

There are, however, plenty of movies on DVD where the telecine is applied prior to encoding (aka hard telecine), and encoded as 30fps interlaced. It sounds to me like you're describing that kind, where the output is already telecined, with 30fps encoded frames. If that's true, again, knowing nothing about how Procoder works, I find it hard to believe that there's no way to telecine it via flags, rather then hard encoding 30fps interlaced. CCE, for example, can encode 23.976fps easily, and either soft telecine it during the encoding, or let you take the 23.976fps progressive output to telecine it via Pulldown.exe or DGPulldown afterwards.

There are some Procoder experts around here that may be able to help you.

[scottrwn98]

Hi-

I know nothing about Procoder, but you're misinformed about at least one thing:

...so when burned to a DVD, it will be 24i (like all movies we buy on DVD)..

Most, but by no means all, movies are stored on the DVD at 24fps progressive (or 24p, iusing your terminology).

Thanks for your response.

Just a quick clarification on this interlaced vs. progressive issue: Film-originated projects do indeed find their way onto the disc at 24i. The frame rate is kept at 24fps in order to conserve space on the disc, since doing a hard telecine transfer would result in redundant frames that unnecessarily eat up precious space on the disc. Additionally, the encoded file must be in an interlaced format, (even though the source is progressive in this instance) or it's not going to be NTSC and, therefore, DVD compliant.

You can find all of this info in Dan Ramer's DVDFile.com article on pulldown methodology from earlier this year. Here's the relevant part:

"When a film source is encoded for presentation on DVD, it is stored at 24 frames per second; each video frame contains all the picture information from each film frame. There is no redundancy or duplication. Such a transfer is written to DVD as 720-pixel wide by 480-pixel high interlaced frames (where each frame contains two 720 by 240 fields), and there are only 24 frames for each second of film. This is known as 480i24. On each DVD encoded from a film source, a flag is inserted within the MPEG-2 data stream that instructs the player to repeat certain fields to reconstruct the 29.97 frame per second interlaced video. The player obliges by performing the 3:2 pulldown in real-time, continually creating interlaced frame sequences just like the one shown in the above figure, "The Telecine 3:2 Pulldown Process for NTSC Video."

You can find the entire article here if you're interested in hearing more:

http://www.dvdfile.com/news/special_report/production_a_z/3_2_pulldown.htm

Anyway- now that that's cleared up- my question restated is this: how can I make a 24i file and have it flagged to be pulled down during playback by the set top player in the same fashion that the film-originated DVD's we buy at the store do it? Is this a proprietary thing, or is there a way for the average Joe to do this at home?

[manono]

You're misreading him. 480i yes, 24i no. Yes, they will be output as fields to a standard interlaced CRT TV set. But they'll be stored as 24 whole frames per second, or 24p. Yes, those frames will be broken up into their component fields upon playback, but it's not called 24i. Yes, because of the drop frame flag and the duplicate fields added as a result of the RFF flags, the 24fps progressive frames will be output as 29.97fps interlaced fields (more properly called 60i). Most, but not all, DVDs use frame based storage, rather than a field based storage. If you want to call it 48i, then I can't argue with you, although I find it a bit misleading. Maybe we're just arguing semantics.

And I also said before, CCE can easily encode to 23.976 progressive. As can TMPGEnc, as can most (all?) MPEG-2 encoders. I haven't personally used Procoder, so I have no idea what it does. A lot of people like it though, so I would guess it can do the same thing with the right settings. By the way, how do you know for sure that you're getting hard telecined 30fps interlaced out of it, rather than 24fps progressive with pulldown applied? What are you using to check?

[guns1inger]

DGPulldown can put the flags in for you once encoded. CCE will encode 23.976 and put the flags in for you on the way. Procoder will encode at 24p and put the flags in as well. This is how commercial discs are encoded as well.

[scottrwn98]

Procoder will encode at 24p and put the flags in as well. This is how commercial discs are encoded as well.

I have ProCoder 2 and what Target settings do you use? I usually put in MPEG2 - DVD - NTSC (not the high quality or mastering quality).

Under Frame Rate, I get three options 29.97, 23.976p->NTSC and 24p->NTSC.

Thanks for your input!

[guns1inger]

I usually use 23.976p because my NTSC source is usually 23.976p to begin with. I also select the NTSC -> High Quality template.

[scottrwn98]

I usually use 23.976p because my NTSC source is usually 23.976p to begin with. I also select the NTSC -> High Quality template.

Well I ment, where is says frame rate, it has three options; one being 23.976->NTSC (3-2pulldown) ... doesn't that just pull it down to 29.97?

And the template, I used CD/DVD -> DVD -> "MPEG2 - DVD - NTSC (Mastering Quality) ... is this what you mean?

:P

[guns1inger]

It encodes at 23.976 fps and adds pulldown flags to the stream. If you have a progressive player with component output to a progressive capable TV it will playback at 23.976p, otherwise it will playback at 29.976, with the player adding the missing fields.

I use the DVD->NTSC template, which uses Highest Quality encoding mode by default. I have found mastering to be slow for no dicernable benefit in many cases, and often for lower quality than the Highest Quality setting.

[scottrwn98]

Awesome, I got it to work ... only problem ...

Exporting a QuickTime Reference says Average Frame Rate is 20.95 (or 21.90)

Exporting a Quicktime Movie Files (AVID DV Codec) it says (23.98).

Both instances, right before ProCoder gets done with about 5-10 seconds of the video, I get program error. ... hmmmm.

I'm on the right track, so I thank you for your input!!

[mikiem]

Apologies for jumping into the discussion here with what might seem heresy, but doing a bit of checking yesterday after a post on similar stuff, I do believe the DVD spec includes 24 fps progressive. I had stumbled on this a few years back in a "What If" situation, and found my cheap apex based players functioned just fine when fed 24p. It makes sense if you remember that the players electronics don't care about an awful lot of stuff we worry about -- they just take the info from the decoder, and send the TV spec video.

That's all said in hopes that it might help shorten your search for a workflow... I *believe" (may of course be wrong), that 24 i is sort of a misnomer, but just sort of. For DVD (& similar) playback to an interlaced device, each frame of 24 p is simply divided into 2 fields, and can easily be reassembled, unlike NTSC or PAL recorded as separate fields originally to DV for example, which cannot be as easily put back together. NTSC DVDs do normally include pulldown flags, using the original 24 p as source, and encoding only that 24 p content -- extra frames are not encoded, so the original goal of saving disc space is achieved. As far as I can tell the practical advantage might be a better, finer control of field creation/doubling, as in the Sony encoders seem to do a much better job of adding pulldown flags then anything else I've come across -- many of the others to my eyes show no difference from just leaving it at 24 p.

Again, hope that helps somehow in finding what works for you, & don't mean to contradict anyone. And of course the final proof is in what works for you.

[adam]

The DVD standard definitely does not support 24fps progressive, AKA no pulldown flag. The reason is simple, its not part of the NTSC standard. Many players do a telecine of 24p footage regardless of whether the pulldown flags are there are not. That's what happened with your Apex, and these are known to be very forgiving players also. You still got 29.97fps interlaced output, the same as if the pulldown flags had been used. But on another player you might have gotten garbage, because a disc encoded in this way is definitely not compliant.

[manono]

Hi-

As far as I know, no DVD authoring app will even allow 24fps progressive output without pulldown. You either feed it an M2V already telecined to 29.97fps, or if it has pulldown ability, it'll add the flagging for you. So either mikiem wasn't playing a DVD on the APEX (MPG perhaps), or without him knowing, the authoring app added the flags for him.

[mikiem]

Well I apologized up front, and do so again, said I was posting what might seem wrong, stated that this was my experience, my beliefs so far, & I thought made the post as a suggestion of something someone might look into if they had a mind to. Even said I didn't want to contradict anyone. But here we go...

Getting 24 p on a DVD isn't hard really -- don't know which authoring software you've been using, manono, or how... And FWIW, can't add flags to an mpg2 without rewriting the file, which is somewhat noticable.


As far as the spec, I could well be wrong, but alas all I can go on is what others have put online, and try to form some sort of consensus from their opinions. As far as I know, most of the actual spec is covered by NDA and is a trifle beyond my budget. Everyone else just works amazing feats from reverse engineering and well, opinions differ. That said, 2 of my sources were the DVD FAQ at http://www.thedigitalbits.com/officialfaq.html & info here: http://dvd.sourceforge.net/dvdinfo/ if it helps.

"The reason is simple, its not part of the NTSC standard." Sorry to all those folks not using NTSC I guess...

Seriously though, the NTSC std is a set of specs covering a broadcast signal. The relation or concern between DVD (or D1 etc.) and NTSC & PAL specs, is the player obviously has to output something the TV can accept.

I do agree that some players, perhaps most wouldn't handle 24 p, and offer apologies if I gave that impression. There are a lot of features in the DVD spec that are not handled by every player, or equally well. My intent was to offer a direction for scottrwn98 to pursue if it helped him out, and as posted: "the final proof is in what works for you." I also said: "and send the TV spec video.", which would be 29.976 i.

So, don't know what all the fuss is/was about.

[manono]

Getting 24 p on a DVD isn't hard really --

I never said it was. I do it every day. I said that outputting 24fps progressive is impossible.

I do agree that some players, perhaps most wouldn't handle 24 p,

None, not even your Apex, will output 24p from an NTSC DVD. Not if you want to see anything on your TV set. And it's not going to do the RFF on its own either, in the absence of pulldown. Want proof? Open one of these so-called 24p-without-pulldown Vobs in DGIndex and go File->Save Project. Open the resulting D2V file and look for the 0 1 2 3 0 1 2 3 pattern

[edDV]

A bit of "simplified" history may help.

Movie DVD material is stored as 23.976 progressive but mechanically the data is split into fields on the disc. This was done to simplify playback electronics for cheap DVD players. These players needed to quickly assemble a 29.97 fps "telecined" output and could do this by simply retriveing the field data in the proper 3:2 sequence to build the output.

The more complex processing burden was placed on the progressive players. Progressive players reassemble the 24p frame sequence but do not output this directly because direct 24p display has unacceptable flicker and appears jerky.

Progressive players repeat full frames in a 3:2 sequence to output at 59.94 frames per second over a 480p connection.

720p and 1080p also output 23.976 progressive sources as 59.94 frames per second using the same 3:2 frame repeat process.

Even film projectors repeat frames to at least 48 fps to avoid flicker.

[mikiem]

My only defense for posting anything beyond my original was I felt unfairly dissed by 1) the suggestion I wouldn't recognise video being re-encoded or written. 2) the suggestion I didn't know what I put on a disc. That said.

@manono,
"None, not even your Apex, will output 24p from an NTSC DVD. Not if you want to see anything on your TV set. "

Don't want to argue or anything, but maybe this example will help clarify a bit... Jpg CDs, VCDs, SVCDs, many digital cameras, all output to a NTSC TV, yet none have *content* that is in NTSC or PAL spec. The hardware involved *generates* a signal that is more or less spec compliant and sends it out to your TV, VCR, recorder, whatever. I say more or less because my AIW TV out isn't 100% spec compliant, neither are many dual format European devices, & I suspect neither is my Kodak. :P

As far as verifying whatever, it's easy enough to create 24 or 23.976 p on capture, using DGIndex, encoding in Vegas and so on. Using DGIndex, that's why there's a force film option, to remove pulldown flags. There's a huge, HUGE amount I don't know, but encoding video since, gosh I think it was around '93, fps is not something I find confusing.

@edDV
Sorry, please take this all FWIW, and really, really am unsure if I should even post this part... [Note: I've removed a bit of it already ]

It's possible I suppose that film is repeated somehow in the projection room, but I've got a trailer reel someone was kind enough to send me for another project, and using my negative scanner for this project, I didn't see the frame doubling you mentioned. Again, FWIW...

RE: Progressive players... I personally have no idea not having the means to grab, capture, or in any way analyse their output. I did read however just the other day a column saying that they perform pretty much like a software player doing the bob - weave routine to get 24 or 23.976 p output. This was by an engineer with IBM CA... no offense what-so-ever intended... I have no idea who's correct, & I'm not taking a stand.

Otherwise I'm outta here. This OT discussion has nothing to do with anything I can determine. Apologies again and again to any inoccents stumbling on this thread, and to the original poster -- offering this apology is actually the main reason I'm posting this at all Thank you edDV for a moderate voice.

[edDV]

@edDV

It's possible I suppose that film is repeated somehow in the projection room, but I've got a trailer reel someone was kind enough to send me for another project, and using my negative scanner for this project, I didn't see the frame doubling you mentioned. Again, FWIW...

The projector gate repeats frames. There are only 24 fps on the reel.

RE: Progressive players... I personally have no idea not having the means to grab, capture, or in any way analyse their output. I did read however just the other day a column saying that they perform pretty much like a software player doing the bob - weave routine to get 24 or 23.976 p output. This was by an engineer with IBM CA... no offense what-so-ever intended... I have no idea who's correct, & I'm not taking a stand.

That is a different subject. We are talking playback and the data is already available as 23.976 fps progressive on the DVD disc. but is output from the player at 59.94 fps per standard. There is no provision for 24 fps playback from a DVD player.