pulldown question

[jaysison]

i just downloaded a movie and converted it using cce one pass vbr. i inserted pulldown on the movie to make it 29.97 fps. my question is, do i have to convert the audio to 29.97 fps? because if i mux it with bbmpeg, the video source has 29.97 and the audio has 23.976. i've done this 10 times and i open vdub-mpeg2 and open the file and it says in video-framerate (the one that says "change so video/audio durations match") that the audio/video is not in sync. there's not much of a big sync here, just a lip sync.

[adam]

29.97fps is the only supported playback framerate in the NTSC standard. When you encode at 23.976fps and add the pulldown flags the DVD player telecines the movie to 29.97fps as it plays, as opposed to having to hard telecine it to 29.97fps yourself during encoding.

During the telecine the framerate is increased by physically creating new frames from existing fields. This means that video itself plays at the same speed, extra frames are just inserted each second. The point is that video/audio sync is unaffected.

You don't have to do anything to your audio if you converted right. I don't understand what you mean when you say that BBMPEG says your video is 29.97fps and your audio is 23.976fps. Audio has no framerate, it simply has a runtime. As long as that runtime matches the video's runtime (assuming you haven't done any improper video conversions) then it will sync up.

Also, just to clarify. When you applied the pulldown flags to your video you did not make it 29.97fps. It is still stored at 23.976fps, it will just be played back at 29.97fps. It is the job of the decoder to perform the necessary telecine on the fly, as the pulldown flags specify.

[jaysison]

so basically i just have to encode the video and then not do anything with the audio? how can you check if the a/v is in sync? i just check it using vdub-mpeg2 and its always not on sync whenever i look at it. and one thing i noticed is, when i played the movie in the computer with and without inserting pulldown, the movie is 154:08 w/o pulldown and the movie with pulldown is 153:59. I never seem to do this right.

[adam]

If I needed to test sync I would use a software player after multiplexing. Some mpeg2 decoders can introduce sync problems, even though the mpg itself is perfectly fine.

If the runtime is changing at all before and after adding pulldown flags then something is wrong. First ensure that your source is actually 23.976fps. I would disable the 3:2 pulldown detection in CCE and use pulldown.exe after encoding instead.

Since you are using a downloaded source there is also the possibility that you have some corrupted frames which are essentially dropped by the encoder. This is quite common with downloaded sources.

[jaysison]

what software would you recommend for playing? i currently have intervideo windvd 4 which says that the movie is only 1:51:59 even if its really 2:34:08.

[adam]

I use WinDVD Platinum. All versions of WinDVD I have tried work great. I think your problem is with your encoding.

[jaysison]

is it really necessary to insert pulldown?

[adam]

If you encode mpeg2 at 23.976fps then yes it is necessary. It will be non-compliant in either the SVCD or DVD standard and it will not play correctly on many DVD players. This really should not be complicated at all. If your source is 23.976fps then simply encode it in CCE but don't enable the 3:2 pulldown detection settings. Then run it through pulldown.exe when you are done. It takes maybe 5 extra mins.

[jaysison]

my cce version is 2.5 and im not sure if it has the 3:2 pulldown detection youre talking about. where can you find it so i can uncheck it?

[adam]

2.5 doesn't have pulldown options. From your initial post it sounded like you were using the pulldown function offered in later versions of CCE. So I assume you just ran your video stream through pulldown.exe after encoding. All this sounds correct, and I really don't understand how the playtime could change after running pulldown.exe. All it does is change header flags.

Are you sure that the encoded output doesn't have a different runtime then the source also? Like I said, you may have corrupted frames which are being lost during encoding. I still think that the pulldown process has nothing to do with your problem, I don't see how it ever could.