NTSC(Film) to NTSC (VCD)DVD

[maduser74]

Friends,

I am struck here. I looked at various threads in this forum and most of them talk about SVCD.
Here is what i wanted to do. Create a VCDDVD with 2 movies. Currently one is in NTSC Film format 23.976 fps and MP2 audio 224 bps. Second one is NTSC 29.97 fps and MP2 audio 224 bps. I NTSC film format was the result of conversion from PAL VCD.

When i used TMPGEnc DVD Author, i got an error saying 23.976 fps cannot be used for a standard DVD. How do i convert this to 29.97 fps.

When i tried DVDMovieFactory, i was able to successfully create a dvd but the output was crappy. I selected CIF as project setting and changed audio to use MP2.

I tried using Pulldown with and without -drop_frame set to true, but the output had fast video.

I am not sure what to do next. Any help would be greatly appreciated.

Thanks
maduser74

[bugster]

Friends,

When i used TMPGEnc DVD Author, i got an error saying 23.976 fps cannot be used for a standard DVD. How do i convert this to 29.97 fps.

maduser74

mpeg-1 @23.97fps is not valid for DVD, AFAIK, the only way to hange NTSCfilm VCD to NTSC VCD is to re-encode.

Also don't forget that for DVD the audio must be at 48khz sample rate.

[maduser74]

Thanks bugster.

I converted a PAL VCD to NtscFilm VCD format as i read in the forum that it is the best approach for PAL to NTSC VCD conversion.

Is there a best way to convert PAL to NTSC MPEG1 instead of going through an intermediate step of NTSCFilm ?

My DVD player doesn't support PAL DVDs. DV525. So i had to convert it to NTSC.

Thanks
maduser74

[bugster]

For VCD, 23.97fps is a valid framerate and is the best bet when converting from pal. For SVCD and DVD, these are mpeg-2. You should also encode Pal conversions at 23.97fps, but use the 3:2 pulldown to tell your player to play back at 29.97fps

[Vejita-sama]

ACtually I don't think that the pulldown flag works for MPEG1 video, only MPEG2. You'll most likely have to run pulldown.exe manually and then use that as your sourse to author.

You seem to be a little confused on framerates. There are three that you are likely to see:

25fps - PAL standard

23.976fps - NTSC FILM
29.97fps - NTSC standard/TV

Here's the short (no really) verison. First you only need worry about pulldown with NTSC (US, Canada and Japan) source. PAL (most of europe) doesn't have this problem.

When TV was first invented it was not possible to have a produce/broadcast a high enough framerate to create seamless motion. So someone came up with the idea of spilting each frame into two fields. Each field would have 1/2 the lines of each frame. One field has all the even lines, and the other all the odd lines. TVs then get 60 fields per sec (ie. 30fps). This works because each field stays on the screen after it's been sent. To the human eye it all looks seamless. This process is known as interlacing.

On the other hand movies are shot at 23.976fps (24fps) progressive. Progressive in that each frame is a complete still image from the movie. The problem is that your TV is set up to ONLY show 30fps interlaced video. So to play films on your TV we need to convert the 24fps/progressive source -> 30fps/interlaced video.

This is done by a process known as teleciding (aka pulldown). For more info check out:

http://www.doom9.org/synch.htm

basically what you do is take four frames of film (ABCD) spilt them into fields, then make new frames:

Frames -> fields -> new frames
ABCD -> AABBCCDD -> AA AB BC CC DD

By this process you find that each 2 new frames are made of 'hybrid' info, and 3 are made from the original source. Hence, 2:3 pulldown (it's actually 2:3 pulldown not 3:2, but that's a who other debate).

So if you have a 24fps/progressive source and want to encode it. You pulldown/telecine. For a 30fps/interlace source you do nothing (unless you're making a VCD).

Now here's where people get confused. If you have a 30fps telecided source (eg. DVD rip) and you want to encode it. You'll get a better result if you first convert it back to 24fps/progressive. This process is known as inverse teleciding (aka IVTC).

So why would we want to do this. Because it produces better encodes. For example:

1850kbit/s video at 30fps = 61.7kbit/frame
1850kbit/s video at 24fps = 77.1kbit/frame

that's a 25% effective increase in bitrate for the same size file!

So now you're thinking great, I should run IVTC on everything. But that would be a mistake. Because you are chaning the framerate. And you can't just do that (HENCE all the PAL <-> NTSC treads). That's also why all those old time baseball clips have everyone moving in fast forward.

Only run IVTC on 30fps/telecided source.

Now besides having a different framerate PAL also uses different resolutions than NTSC. Because just chaging the framerate causes problems what most people recommend for converting a PAL to NTSC video is to convert from 25fps -> 23.976fps -> 29.97fps

Ok that really was the short verison. Hope this helps. Any other questions?

[maduser74]

ACtually I don't think that the pulldown flag works for MPEG1 video, only MPEG2. You'll most likely have to run pulldown.exe manually and then use that as your sourse to author.

I did run pulldown.exe on the MPEG 1(23.976fps) source with following options.
-drop_frame true
-drop_frame false. (The output was faster in this case)
In both the cases, i got the same file size.
After pulldown does the frame rate is changed ? Is it possible to use the pulldown video into a DVD ?
Will this command do the job ?
"pulldown.exe "cd1.m1v" "cd1_pulldown.m1v" -drop_frame true"

Because just chaging the framerate causes problems what most people recommend for converting a PAL to NTSC video is to convert from 25fps -> 23.976fps -> 29.97fps

I guess i am half way through this. I did convert successfully from 25fps to 23.976 and struck at converting to 29.97 fps.

[adam]

Adding pulldown flags to your stream doesn't change anything about your video, it simply gives the playback device an instruction to perform a telecine at playback. Your video is still 23.976fps, it just gets played back at 29.97fps on anything that recognizes the 3:2 pulldown flag.

Don't run pulldown on mpeg1 files, its not supported. The hardware playback device won't recognize the flags and won't perform the telecine and the playback will be unwatchable.

If you want to transfer an NTSCfilm VCD to DVD, then you only have two options and both of them require re-encoding. Your first option is to perform a hard telecine to 29.97fps. TMPGenc has this feature on the advanced tab with the 3:2 pulldown filter, not to be confused with the 3:2 pulldown while playback option on the video tab. This feature should work for you in most cases, but depending on how your VCD was made it may not. VCDs (mpeg1) do not support interlacing, so if the VCD was made from an interlaced source then half of the fields may have been thrown out, in which case a telecine is now impossible. If the VCD was made from an NTSC DVD, then you should be fine.

Your second option is to convert your NTSCfilm VCD to a PAL DVD. Just speed both the audio and video up by 4% by following one of the guides on this site. Obviously there are drawbacks to converting to PAL when you live in an NTSC region, because the disk will only be playbable on dvd players that can convert PAL to NTSC.

[adam]

Sorry, I just read up and realized that your source for the NTSCfilm VCD was in fact PAL.

If you have to re-encode anyway to get to NTSC, then you might as well just encode to 23.976fps mpeg2. There is no problem in mixing mpeg1 and mpeg2 content on a DVD, and this way you can store this video at 23.976fps and let the player telecine it to 29.97fps. This way you avoid the difficult and sometimes impossible task of trying to telecine an mpeg1 source.

[bugster]

There is no problem in mixing mpeg1 and mpeg2 content on a DVD,

Doesn't this depend on the capabilities of the authoring app (i know the DVD spec allows it, that doesn't mean your authoring app does).

Adam, do you know which commonly used authoring apps allow this, I can't claim to have ever tried.

[adam]

Well Scenarist does but that's all I use so I don't know of any others. But it is very easy to do with any authoring program you just have to author the VTS titlesets separately. Go ahead and make your project with your mpeg2 assets and use a dummy track for where the mpeg1 track would go. Then do a separate project and just author your mpeg1 asset. Then copy the newly authored vob over the old one, and run ifoupdate and it should work fine.

[funkguy4]

Try TMPGEnc DVD Author, I know it does multiple VTS, which should allow for the MPEG format mixture....ask Adam, he's knowledgeable