NTSC to NTSC Film

[poonaner]

If i do this am i gonna have sync problems as if i were converting Pal to Ntsc?

I've been searching with no luck

[BJ_M]

why would you do this ? there is no reason to do this if the source was not film to begin with ..

[poonaner]

KVCD is why....

[Conquest10]

kvcd is why? why would that be? you can still use 29.97 if that is the framerate of the original.

[johneboy]

If i do this am i gonna have sync problems as if i were converting Pal to Ntsc?

I've been searching with no luck

I convert my DVDs to kvcd all the time from 29.97 -> 23.whatever
anyway, never ran into a audio sync... i believe thats only a problem when your converting from a lower frame rate, to a higher one.. ( i think.. ).... but yea, never had any problems

[adam]

No you definitely cannot just convert from 29.97fps to 23.97fps. Depending on how you do the conversion you will either lose %20 of your frames=very choppy, or slow the speed down by %20=super slow motion.

Film originates at 24fps. To get it to 29.97fps it is interlaced and then the fields are repeated in a 3:2 pattern. New frames are literally created from exising ones. In order to reverse the process you must remove just these frames (fields). The only way to do this is through an inverse telecine, but this is not possible with all sources.

Load your file in TMPGenc and preview it. Go through it frame by frame. If you see 3 good frames and then 2 interlaced frames and this pattern repeats then it can probably be inverse telecined. TMPGenc has an inverse telecine option but personally I dont think it works very well. The best way to do it is probably through avisynth and decomb.

If your movie does not follow the pattern above then you are probably stuck with 29.97fps. There are lots of ways you can get a 29.97 source which can't be inverse telecined. DV is not film, so it doesnt' originate at 24fps. Most tv broadcasters use bizarre telecining patterns and you can't really perform a proper IVTC. And of course if you downloaded this file then there is no telling what the original encoder did to it.

[johneboy]

No you definitely cannot just convert from 29.97fps to 23.97fps. Depending on how you do the conversion you will either lose %20 of your frames=very choppy, or slow the speed down by %20=super slow motion.

Does TMPGenc do this automatically?
Cause I do this all the time, and i have never run into a problem.

[johneboy]

also... i would think if you were ADDing frames... example
24fps -> 30fps...would cause slow motion.. cause now you have 30frames every second, instead of 24..

[mkaiser]

30 fps wouldn't cause slowdown.

Why? 24 frames per "SECOND" or 30 frames per "SECOND"... keyword being "second".

[adam]

By default, whenever you do any kind of framerate change in TMPGenc it simply adds or removes frames to make up the difference. This can make for some very choppy playback depending on how big the fps change is. Adding frames does't really make the playback appear slow, because it is not duplicating every frame, just random ones. Just think about it, you got frames 1, 2, 3, 3, 4, 5, 6, 6, etc... Everytime one of those repeated frames comes up it will appear like playback has haulted for a split second. It is two identical frames so it looks like it is just stuck on the same frame for too long. I'm suprised you don't notice the choppyness when converting from 29.97fps to 23.976fps. It is extremely distracting to me and even my family sees it, and they can't tell the difference between DVD and VHS. Watch a scene with fast motion, it should be very obvious.

If you click the "do not frame rate conversion" filter in the advanced setting than TMPGenc will not add or remove any frames, it will physically speed up or slow down the playback speed. Obviously this can make for some very unnatural looking video if the fps change is large.

[johneboy]

OK, maybe im just dense here.. but this isnt sinking in for me...

for example..
lets say we had a clip at 8 frames per second

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8

we wanted to INCREASE the frames per second to 10

123445 5 6 7 8 123445 5 6 7 8 123445 5 6 7 8 123445 56 7 8

going to repeat some random frames... so it would show MORE frames in a second.. therefore, making things appear to slow down

now lets say we wanted to DECREASE the frames per second to 6

1 2 3 5 7 8 1 2 3 5 7 8 1 2 3 5 7 8 1 2 3 5 7 8

this would be showing LESS frames in one second.. making it play faster if anything..

Is this right?
cause now i have just confused myself.. a tad bit more

[Laddydaddy]

Most films made in the ntsc format are made in the film mode (23.97 FPS).
A 3:2 pulldown is utilized to make them 29.97 FPS. If you use DVD2AVI you can convert the film back to 23.97 FPS. You will get a dv2 file and a wav file. The dv2 is the picture, the wav is the audio. Load both into TMPG in the proper locations and you can convert the rip using the NTSC film template giving you the desired 23.97 FPS. You will have no sync problems. You can also use the vfapi converter to make a fake avi file and frame serve from virtual dub. Instructions on how to do all of this are in the guides on this site. The programs I speak of are freeware you can download from the tools section of this website.

[adam]

no johneboy adding or deleting frames is not going to give the appearance of any speed change, its just going to make it choppy.

Most of the frames will be normal, ie: 1-6 will be the same, but then the 7th frame will repeat. So everything will be fine and then it will just appear to freeze. Play for a while, freeze, etc etc...

If you remove frames then you are losing parts of that movement. Say it shows 10 frames for a guy to move his hand into his pocket. Well if you cut out half of those frames then you still have frame 1 (start of hand movement) starting at the same point in time and frame 10 (hand in pocket) ending at the same point in time, but somewhere in the middle parts have been removed. Its the same movement being done in the same amount of time but now its just jerky.

The only way to change the SPEED is to physically change the SPEED, not just the number of frames.

To see an illustration just try it yourself. Do a big fps change in TMPGenc at the default settings. It should appear choppy. Do the same coversion but with the "do not frame rate convert" filter tab and sit back and laugh at how fast or how slow things move.

[adam]

I didn't even realize this was posted in the DVD ripping to... forum. As Laddydaddy suggested, if your DVD is NTSC than %99 of the time you can just use dvd2avi to preserve the original 23.976fps by enabling forced film, and no it has no effect on audio sync. NTSC dvds aren't actually encoded at 29.97fps, they are encoded at 23.976fps and use pulldown flags to play it back at 29.97fps.

My previous posts were made with the assumption that you actually had a 29.97fps source.

[poonaner]

Whoa lots of posts since i last checked,

Anyways thank you for your input, now that i know this information that dvd's are not encoded in NTSC but rather NTSCFilm and that its possible to get the original NTSCFilm off the DVD then i see no need for this question to continue to be answered.

Thank You