The Mummy Returns - Anamorphic Confusion

[Akai Rounin]

OK, so The Mummy Returns is 2.35:1 aspect ratio, right? Well, not really... That's what it says on the box, but when I ripped the movie TMPGEnc said it was 720x480 pixels, and letterboxed, NTSC (525 lines). OK, that's no problem - 720 pixel wide 2.35:1 letterboxed video should be 304 pixels high, right? Wrong. This viewable video area is 720x368 pixels instead. That corresponds to 1.93:1 aspect ratio, not 2.35:1, so what gives?

OK, I took a close look at the opening UNIVERSAL logo and realized that at either 720x480 or 352x240 pixels it was somewhat distorted, stretched along the vertical axis, as the Earth looked more like an egg than a ball. Ah, I had a hunch and decided to check it out. Presto! I was right this time - a hasty switch to a 16:9 aspect ratio in Sasami2k and a test clip showed the proper way! Even in full screen mode the globe was perfectly round as it should be. Another look at the box, and there it was plain as day "2.35:1 ANAMORPHIC WIDESCREEN". Heck, it might as well have read, "WARNING: Objects in mirror are closer than they appear."

None of this would be too much of a problem if I weren't trying something rather different. You see, I was experimenting with the Dreammovie VCD Player for Sega Dreamcast and learned a few things. It supports non-standard screen resolutions in addition to 352x240 and 352x288. In particular, it supports 352x480 pixels as an apparent upper limit. Anyway, I'll probably just use Clip Frame combined with an Arrange Method of Center (custom size) to set this to a 352x304 viewable area on The Mummy Returns. I could likely get away with making it 352x368, but I don't want to use the bandwidth if it isn't necessary. Besides, I'm too lazy to keep resizing the frame size on-screen (though it is a handy feature of Dreammovie). [NOTE: I tried 352x576, but that wouldn't display on a NTSC television set. It seemed to lock up the system too.]

So, I wanted to try encoding my DVD rips to 352x480 from now on. I figured I could view them on television using the Dreamcast and on PC otherwise. I chose The Mummy Returns as the first of these. This may have been a mistake though. It's the only movie I've attempted to encode so far that seems stuck at a 23.976 fps rate. [I'm not sure, I may have chosen Force Film in DVD2AVI.] So now I have to figure out how to use the 3:2 Pulldown command from the Advanced menu.

Oh well, I'll report back if I figure this out. If anyone has any suggestions, feel free.

Toyoniya Hiyaku, Noromuoy!

Akai Rounin, The Cyber Sage

[Akai Rounin]

Forcibly Filmed...

OK... Well, this is the part I have a problem with:

Sefy wrote, "Step 1d - This is an Optional Step! - Some movies may come in the Film format which is 23.976 fps instead of the regular NTSC 29.976, so you might want to enable the Force Film feature of DVD2AVI, go to the " Video" menu and select "Field Operation" and then press on the "Forced FILM" and this will create a D2V file using 23.976 fps."

poopyhead wrote, "FILM, progressive =>enable force film in dvd2avi and use the NTSC FILM template (not NTSC template) in tmpgenc

NTSC, interlaced => disable force film in dvd2avi and use the NTSC template in tmpgenc"

I am trying to figure out what is going on with The Mummy Returns, Region 1 DVD. In DVD2AVI it shows as:

Aspect Ratio - 16:9
Frame Rate - 29.97
Video Type - FILM
Frame Type - Progressive

So here's the question: Why should I choose FORCE FILM at all, if DVD2AVI says the video is ALREADY 29.97 fps...??? In other words, if DVD2AVI does not say the Progressive FILM is 23.976 fps, then why should I Force Film? Should I simply presume that any movie that is Progressive FILM is ~*automatically*~ a 23.976 fps DVD?

My problem - no crappy interlace artifacts appear in TMPGEnc when I select an area of the movie to test using Source Range. However, I get interlacing artifacts every time I try to encode the clips to MPEG-1. Why? Is it because I am sizing the video to 352x480 instead of 352x240?

HUN-YA

Akai Rounin

[LeeBear]

Okay first off when a movie says it's "anamorphic" it just means it's encoded with a display aspect ratio of 16:9 it has nothing to do with the actual aspect ratio the film was shot in. 16:9=1.77:1 which as far as I know no film is ever shoot at the ratio. Most films use a 1.85:1 or a 2.35:1 ratio, so even if it's encoded for "anamorphic" when it's put on a DVD there's still some black lines at the top and bottom added (not as much as if it was encoded for 4:3 letterbox). Remember only 16:9 and 4:3 are valid display aspect ratio's for DVD's.

Okay your next qustion about why you would choice "force film" in DVD2AVI. Basically movies (films) are usually shoot at 23.976 fps but video (ntsc tv) is 29.97 fps. So when a film is mastered onto DVD they have a problem the framerates are not the same. What they do is encode the movie at it's original frame rate of 23.976 and then use a process called pulldown to add special flags to repeat certain frames so they can get a 29.97 frame rate. Why would they do this? Because these special flags basically take up no space so the encoder isn't wasting it's time encoding the repeated frames like you have to do if you did a true frame rate conversion to 29.97fps. That roughly means each "true" frame is able to get about 20% more bits in the encode and thus better picture quality.

This brings us to why you would want to use force film on DVD2AVI. Basically force film will reverse the process and remove the special flags so you get back the original 23.976 frame rate. Since AVI's can be pretty much any framerate you'd want to do this because there's no point in wasting bits encoding the repeated frames like you would if you didn't use 'force film'.
So in summary:
-if you use 'force film' your AVI will have a finally output of 23.976 fps
-if you don't use 'force film' your AVI will have a finally output of 29.97 fps, and a bigger file size or lower quality (20% of the bitrate is used to encode the repeated frames)

-LeeBear

[Tearren]

-LeeBear

Thank you so much for your explanation of why to use force film on DVD2AVI. I have been struggling to understand and your explanation helped shed some light on the topic for me.

Could you possible take the next step and explain exactly what settings to use in TMPGEnc to create a VCD with frame rate of 23.976? I have been making my VCD's (using KVCD template) but at a frame rate of 29.97. Would I select 3:2 pull down under advanced? I have tried several ways but never manage to get it to play correctly in my DVD player. The result is always jerky.

Thanks,
Tearren

[Bel]

In addition to 3:2 pulldown, also select Inverse Telecine filter. Don't really understand it all, but that's what I do and it seems to give good results.

[LeeBear]

Bel: You wouldn't use the Inverse Telecine filter unless you know the source has been telecine in the first place. I've never run into a movie that was telecine. The only time I can think of where you might use IVTC is for anime.

Tearran: if your source is 23.976 fps then you should not have to do any sort of frate rate conversion since 23.976 fps is a valid VCD frame rate and your DVD player should perform the 3:2 pulldown on the fly while it's playing back. I don't use the KVCD template so I cannot help you directly. I've tried it before but got skipping audio and occasion pausing video, maybe because the settings are pushing the limits of a valid MPEG1 stream for the DVD player.

In general though your settings for TMPG would be like this:

-If source is 23.976 fps you should set your VCD output framerate to match (23.976). "Don't" check 3:2 pulldown or Inverse Telecine

-if your source is 23.976 fps and for some odd reason you want to make your VCD have a framerate of 29.97 fps then you "would" check 3:2 pulldown to create the extra frames. The important thing to remember here is that MPEG1 (VCD) does not support the special flags that tell your player to repeat frames (like on a movie on DVD) so these new frames are physically encoded, so you basical waste 20% of the bitrate on encoding these duplicate frames.

-3:2 pulldown is really only useful when converting to MPEG2 (SVCD or DVD) because 23.976 fps is not a valid framerate for SVCD or DVD's. So you would need to create the fake frames with pulldown to make a valid MPEG2.

-LeeBear

[Bel]

Bel: You wouldn't use the Inverse Telecine filter unless you know the source has been telecine in the first place. I've never run into a movie that was telecine. The only time I can think of where you might use IVTC is for anime.

Ok, I admit it... I am now thoroughly confused on this issue. I would ask questions, but I don't know where to begin... What I've mainly been doing is converting svcds and dvd rips to dvd. When run through dvd2avi to save the project for tmpgenc, they pretty much all tend to say 99% film, which means its a 23 fps stream with pulldown, correct? As I said, I don't know what the hell inverse telecine does, but the one time I tried encoding without it, My sound gradually grew out of sync, like I was playing 23 fps without adding the extra frames somewhere.

As I like to encode my dvds with a lot of stuff on them I tend to use half d1 resolution and low bitrates, therefore having all of my stuff playing at 23 fps with pulldown gives me a noticeably better picture quality. I just noticed extreme chopiness on a couple of the shows I converted on my last dvd however, so I'm not doing something correctly. Anyone know what the hell I'm doing wrong and how to fix it? Also, you said only use inverse telecine if the original movie has been telecine's... Now, what the hell is a telecine?

Thanks,
Bel

[LeeBear]

Bel: Sorry for the confusion. Okay telecine is basically the 3:2 pulldown process to convert 23.976 fps film rate into 29.97 fps video rate. Invere Telecine is basically a 2:3 pulldown to get the 29.97 fps back to it's original 23.976. The reason I say you should not have to check "Inverse Telecine" in TMPG is because if you choose "force film" in DVD2AVI then you would of already done that process so you wouldn't have to check that in TMPG. If you didn't check force film in DVD2AVI then you are right you would check "Inverse Telecine" in TMPG. I still don't see a time when you would check both "Inverse Telecine" and "3:2 pulldown though" since you'll be basically taking a 29.97 fps IVTC back to it's original 23.976 fps, and the telecining it back to 29.97 fps. Seems kinda pointless does it not?

Akai Rounin: I forgot to answer one of your quesiont. You said your MPEG1 encode of the mummy has alot of interlacing, it might be a field order problem. Try changing the field order.

-LeeBear

[Bel]

Leebear,

Thanks for the reply. I agree that it sounds kinda pointless in theory. The one time I had that sync problem that I discuss above was when I forced film, set 3:2 pulldown, without the inverse telecine. I'd like to say that "I" did it, but it was really the TMPG wizard, because as I said I just started using 23 fps for dvds. Was there some step I missed regarding the process?

heres what I did in short:
-demux .m2v and .ac3 stream from dvd
-save project in dvd2avi with force film on
-converted to dvd mpeg2 half d1 res, 2000 cbr (may have been a bit higher don't remember), 3-2 pulldown on, no Inverse Telecine or any other filters.

The picture looked good, however as I said the picture went out of sync with the sound slowly but steadily as it went on, as if my 23 fps was not getting pulled down to 30 fps (wouldn't it be pushed up?)

Also, is there a good program to identify fps in an mpeg source as well as field order? Even when I don't use the tmpgenc wizard, I tend to run the file through it as it determines the correct field order all by itself. Is there another way to do so?

I appreciate the help, this is by far the most confusing topic I've run across with this hobby.