Frame Rate Conversion Issue

[vegasincident]

Few quick questions. I hope that some can post a clear and cogent answer.

1. I have a certain new centropy release that everyone is probably tired of talking about. It is in PAL format. When I convert to NTSC (SVCD) with TMPGEnc I get an Audio sync problem. Audio is correct initially and slowly shifts to preceed the film by 5-10 sec near the end of Disc 1.
I assume this has something to do with 25 fps to 29.97 fps. I've seen
NTSC(Film) shown as 23.976 fps but in TMPGEnc the SVCD Template which came with it shows fps for SVCD(NTSC)Film as 29.97 fps. Just an oversight I'm sure. In short I'm looking for the simplest solution. Would demuxing the mpeg from the CD then converting only video to NTSC then remuxing with original audio make any diiference?
I understand how to use goldwave and insert or delete audio and I know how to stretch the file. I'm trying to avoid doing this with every PAL release I get so if someone knows a simple way to for PAL to NTSC transfer keeping audio intact and in sync please post. I have not tried to encode to NTSC(Film) because I'm assuming the sync issue will creep up again.

2. Secondly, is it possible to transfer from PAL to NTSC at 25 fps across the board? Wouldn't that just be an XVCD? My stand alone dvd will play
XVCD, and if only the resolution were changed during transfer that seems like it would eliminate the audio problem. I don't know much about TV compatibility and frame rates though. Any input would be greatly appreciated.

Thanks...

[adam]

1. Ntsc and ntscfilm both have the same runtime. They originate at the same source, film which is 24fps. Ntscfilm is just slowed down slighlty to 23.976fps, from here ntsc is created by adding fields. Basically for every frame added, it is sped up by that much as well, so the runtime always remains the same.

Pal is done completely differently. Since 25 fps is so close to the 24fps that film originates at, the film is simply sped up by %3. Since it is actually running faster, the runtime is %3 shorter.

So you see you are mixing and matching conversion methods by going from pal to ntsc. Your audio and video are not running at the same speed. This conversion can be done but its not ideal.

The best thing for you to do is convert to ntscfilm which is 23.976fps, despite what any template you have may say. Film is simply slowed down to ntscfilm and it simply sped up to pal...since no fields are added you should not lose sync with this conversion because you are only changing the speed. If you convert audio and video together I believe you will be ok. If the sync persists then you will need to slow your audio down by about %3.03 and then remultiplex with your 23.976fps video stream.

Since you are making a svcd you need to use the 3:2 pulldown flag. This will instruct your dvd player to do a real time telecine to 29.97fps as it plays.

2. Some dvd players are more leniant than others about certain aspects of your (s)vcd, allowing you to create an x(s)vcd, but tvs are utterly unforgiving. Most pal tvs can actually play both pal and ntsc sources but ntsc will definitely not support pal sources. The ntsc standard calls for 29.97fps video and will accept nothing else. When you encode at 23.976fps it is telecined to 29.97fps as it plays, assuming you encoded and authored correctly.

It is not a good idea to mix and match regional formats ex: 480x480 @25fps or 480x576 @29.97fps. This almost always will lead to playback problems.

[vegasincident]

Thanks Adam. You gave me exactly the info I needed, no more, no less.
People like you keep this forum going.

[Yury Perschin]

Hi vegasincident!
Recently I have same problem. I have divx files make from film (approx 24 fps frame rate). I try many case for converting to XSVCD using TMGEnc and CCE and VirtualDub and avisynth as frameserving. Best solution not increase framerate (I have film with 24fps) only equal or less I decrease to NTSC film and get good result. All try to increase framerate pulldown to 30fps give jerky video.
With kind regards Yury.