WHAT IS THE DIFFERENCE BETWEEN 23.97 NTSC AND 29.97 NTSC????

[MrMochila]

hi i am wondering what the difference is between 23.97 ntsc and 29.97 ntsc. does 1 have better quality than the other, and what do both stand for? does it matter which 1 i use. is a movie in a specific format, like is a movie in 23.97 or 29.97?

[snowmoon]

Movies are in 23.976, but TV's require 29.97. Not to worry, in TMPGenc you enable 3:2 pulldown on playback and a 23.976 encode will become 29.97 automatically.

[SingSing]

When watching SVCD retrieve and encoded at flim rate,
there are a lot of interlace artifact.
Even I analog downconvert to VHS, ( or SVHS ).

Does 3:2 pull down increase interlace artifact ?

[snowmoon]

SVCD at film rate on the PC should show NO INTERLACED ARTIFACTS. If you do their is a problem with yout method.

3:2 does not add or remove artivacts, all it does it make 23.976 playable at 29.97.

[Nelson37]

This depends on what the video was originally created with. If the original fps was 24, a process called Telecining is used to duplicate fields (NOT frames) to acheive an "artificial" 30 fps. These duplicate fields can only be removed using IVTC, which restores the original 24 fps. It is important to understand that the video REMAINS UNCHANGED from the original, there are just 20% fewer fields to encode. The 3:2 pulldown on playback instructs the player to perform the telecine process in hardware.

Some videos are actually created at 30 fps, and for such films this technique will not work.

[Treebeard]

So heres a question?

dvd2avi will say its 29.97 fps but says type is film - in this case do you tell tmpgenc to do 23.97 and have it do 3:2 pulldown?

dvd2avi will say its 29.97 fps and type is ntsc -- then do you tell tmpgenc to do 29.97 and not hat 3:2 pull down?

i have had the 1st scenario and in tmpgenc i didnt do the 3:2 pull down i just said 29.97 fps. when and when dont i use the 3:2 pull down and how do i use it properly. also what do you do when dvd2avi says type film90% what does the % actually mean. The movies i have made seem to be fine but if using 3:2 would improve them then help me

[snowmoon]

Yes, and Yes.

If you forgot the 3:2 pulldows you would just have a duplicate frame every 5 frames. Motion would not be 100% smooth.

Then DVD2AVI says XX% FILM it just means that the mpeg-2 looks to be film that percent of the time. Generally if this is above 20% then you can force film ( though not guarenteed - see hybrid films ).

And yes, only films ( or other telecined materal ) are appropriate for this. Films that are mixed or hybrid should be handled with an adaptive IVTC like AVISynth decomb or TMPGenc's IVTC filter.

[kitty]

The smartass answer is: 29.97-23.97=6 frames a second

[banjazzer]

Movies are in 23.976, but TV's require 29.97. Not to worry, in TMPGenc you enable 3:2 pulldown on playback and a 23.976 encode will become 29.97 automatically.

I don't use this method as I encode to PAL, but I am interested to know the correct way to encode with 3:2 pulldown.

If I start with an NTSC(film) avi would I use the NTSC(film) template and select the 3:2 pulldown filter, ending up with a 23.976 fps mpeg which would play back at 29.97fps? Or would I use the NTSC template with pulldown?

[snowmoon]

NONONO..

If you select the template you should be OK. DO NOT use the 3:2 filter that will re-interlace prior to encoding.....

There is a checkbox 3:2 pulldown on playback.... use that.

[Treebeard]

but which template do you select --> videocd(ntsc) or --> videocd(ntscfilm)

i understand not to use the filter but use the check box

[banjazzer]

If you select the template you should be OK. DO NOT use the 3:2 filter that will re-interlace prior to encoding.....

Why should it re-interlace?

There is a checkbox 3:2 pulldown on playback.... use that.

Whereabouts? I can only see the 3:2 pulldown filter.

[Treebeard]

i think your right its a checkbox that just says 3:2 pulldown
if you hold your mouse over it it says converts 24fps to 30fps so this has to the correct thing to check. i also think you use the ntscfilm template because that sets fps at 23.97 and the 3:2 pull down ads the 6 frames

[adam]

There are two separate 3:2 pulldown options in TMPGenc.

The one in the advanced tab physically converts your 23.976fps film to 29.97fps. It does this through a proper 3:2 telecine which requires that the source be interlaced first. So it interlaces your source then repeats every first field in a 2:3 sequence. This results in 29.97fps footage, new fields are created where they didn't exist before, but since it is only fields and not frames, you don't notice it.

The other 3:2 pulldown options is called" 3:2 pulldown when playback" and is located on the video tab. This option will ONLY work for mpeg2 and it doesnt actually do anything to your film. All this does is a apply a 3:2 pulldown flag to your video stream so that when the dvd player, hardware of software, plays your movie it does a telecine to 29.97fps in real time. This is the preferable way to encode ntsc material because you only have to encode 23.97fps, which means %20 less frames and effectively %20 more bitrate, yet it still gets played back at the ntsc required 29.97fps.

All dvd players seem to be able to recognize this flag and properly telecine SVCDS and DVDS. Vcds do not require this flag and are supposed to be autotelecined by all vcd compatible players, and most do. However there are some players which apparantly aren't built to spec and this is why you might want to hard telecine your footage using the 3:2 pulldown option in the advanced tab.

[banjazzer]

Thanks for the info. When I experimented recently with a small 23.976 avi using 3:2 pulldown it still came out as 23.976. Is this because it was not interlaced? Or should I have used the NTSC template with 3:2 pulldown? What would you do in this situation - presuming you didn't use the 3:2 playback option, which seems to be the preferred option?

[Treebeard]

So let me get this right if im making vcd's i dont need to worry about 3:2 pull down. even if dvd2avi says type is film. so the right template for vcd's is the videocd(ntsc).mcf correct. i wont use the film one.

but on svcd's i do worry about the 3:2 pulldown. and apply the 3:2 when dvd2avi tells me its a film type

[snowmoon]

All dvd players seem to be able to recognize this flag and properly telecine SVCDS and DVDS. Vcds do not require this flag and are supposed to be autotelecined by all vcd compatible players, and most do. However there are some players which apparantly aren't built to spec and this is why you might want to hard telecine your footage using the 3:2 pulldown option in the advanced tab.

VCD's dont support the 3:2 pulldown FILTER since they are only one half frame. If you do work with Xx480 then 3:2 filter can be used. Attempting to use it on Xx240/288 materal will be disasterous. This is why DVD players are required to handle this situation themselves.

[Nelson37]

NOTE THE DIFFERENCE -

IVTC REMOVES the artificial 3:2 pulldown which has already converted the native 24 fps to 30. There is no visible change to the video, but there are 20% fewer frames to encode. This is the easiest, most dramatic improvement you can get at NO COST in filesize.

3:2 pulldown on playback instructs the DVD player to recreate this 24 to 30 fps increase, and is necessary as SVCD does not support 24fps. This merely inserts a header flag into the file. The file is still 24 fps but will playback at 30fps. Leaving out this flag will cause jerky playback, not duplicate frames. Duplicate frames are usually an artifact of incorrect IVTC or from resizing or de-interlacing a telecined video.

IVTC can absolutely used for VCD, run it before resizing. VCD supports 24fps playback so the 3:2 pulldown on playback is not needed.

[banjazzer]

That has clarified things. Just a final question. When would the 3:2 pulldown filter be used?

[adam]

VCD's dont support the 3:2 pulldown FILTER since they are only one half frame. If you do work with Xx480 then 3:2 filter can be used. Attempting to use it on Xx240/288 materal will be disasterous. This is why DVD players are required to handle this situation themselves.

Ahh yes I should have realized that. I must say I never actually use this filter since every dvd player I have ever tested has had no problem with ntscfilm vcds.

Banjazzer, you would only use the 3:2 pulldown filter if your dvd player did not play ntscfilm vcds and your source had full frames, XXXx480. So really this will rarely happen.

[banjazzer]

Thanks. I'm a bit clearer now than I was. All this makes the PAL system seem so much simpler. 8)

[Martyn1980]

Pal is less stressful, though some people say that the increases framerate ruins certain stuff like music videos,even though NTSC drives me mad ,though my DVD player plays 23.976fps perfect on VCD/SVCD's anyway, so i dont have to worry.

It actually plays it jerky at 29, well not jerky,just a kinda unreal motion, strange thing though, its not really noticable on SVCD rips i download, but if i do a a NTSC SVCD using DVD2SVCD it is.

[Cornucopia]

darn it, kitty
you go the jump on me on that one,

6 Hz!
That's like "What that so-and-so movie about?" About 120 minutes.

Scott

[Treebeard]

[quote]

NOTE THE DIFFERENCE -



3:2 pulldown on playback instructs the DVD player to recreate this 24 to 30 fps increase, and is necessary as SVCD does not support 24fps. This merely inserts a header flag into the file. The file is still 24 fps but will playback at 30fps. Leaving out this flag will cause jerky playback, not duplicate frames. Duplicate frames are usually an artifact of incorrect IVTC or from resizing or de-interlacing a telecined video.

Thank you Nelson37 i have been messing with svcd's and had given up hope b/c nobody could help me. my svcd's kept playing jerky on my tv and people kept telling me it was b/c of the wrong field order. And of course i tried that and it wasnt. This sounds exactly like my problem. i will have to try it out I hope this is my problem and i can start making some wonderful svcd's now.

[snowmoon]

Ok...

wrong field order can be seen during movement when it almost appears that the movement jerks forward and back THIS IS WRONG FIRLD ORDER.

Duplicate frames can be seen as subtle pauses in motion, causing the motion not to be quite as fluid.

[Treebeard]

No disrespect meant to snowmoon ( who suggested it was field order )
i obviously dont know enough about this yet and it was a good suggestion it just happened to not be my problem.

[dmonty]

THE DIFFERENCE BETWEEN 23.97 NTSC AND 29.97 NTSC......

The answer is 6 NTSC.

[Treebeard]

Glad to see you passed elementary mathematics Dmonty 8)

[banjazzer]

The answer is 6 NTSC.

2.5 days for that calculation. You need a faster PC. 8)

[dmonty]

The smartass answer is: 29.97-23.97=6 frames a second

Crapo. I just read all the posts. Kitty beat me on this one. I hate it when I'm out smart-assed.