Framerate Pulldown: 24fps to 29.97 fps - How to do it ?

[Taeranmoondance]

Greetings.

The site has been quite good for as to giving me information for almost everything I needed during my DVD-Video-making carreer.

I have successfully converted almost 20 films now, but something came up I don't know how to overcome.

I have an AVI with a framerate of 24 fps ( reported by GSpot ).
Now, usually, when the movie has 23.976 fps, I use the Pulldown utility to add the extra frames; and in the forum people claim that 24 is basically the same as 23.976. But I don't think so, since the *.M2V created with CinemaCraft plays with a shorter playtime than it is supposed to ( in Media Player ).

When I eventually make the VOBs, it becomes evident that the sound is off-set.

My 2 questions:
1 - is there a Pulldown utility specifically for 24 fps sources, or is it really the same as 23.976 ?
2 - Even if the fps is 23.976, when we perform a pulldown on the video, what must we do to the audio, which we strip in advance and convert to AC3 ?

Thanks for any information

Live Long And Prosper

[bugster]

open the avi in virtualdub and change the framerate to 23.976fps. Either save out a new copy of the avi or better still frameserve to your mpeg encoder. Encode to mpeg (video only) at 23.976fps and add 3:2 pulldown.

For the audio, I suggest waitiing till your video is complete and check the length in WMP (about the only thing it is good for!). Then open the avi in goldwave, adjust the length using 'time warp' (I think) and save as wav. Encode the wav to Ac3 as normal and author.

[Taeranmoondance]

Thanks for the reply, I will try it ASAP, and will give news on the results, for others that might follow.

Live Long And Prosper

[tompearson]

You could also try running it through DVD2SVCD and create DVD's with it using the bitrate tab and changing the output to DVD instead of SVCD.

This program has everything apart from encoder and as you already use CCE just point the proggie to CCE and choose 3 pass for good quality tho 2 is sometimes enough.

It does pulldown automatically and quality is usually superb including audio synch!

Tom

[Taeranmoondance]

Hello again !

I did the video conversion as bugster sugested and it worked.

Yet, when I convert the audio, it goes like everyone is speaking in slow motion. Was it because I ripped the WAV from the AVI ( direct stream copy ) and loaded it into Goldwave, instead of loading the AVI itself ?

Life Long And Prosper

[bugster]

Was the converted audio the correct length?

Stripping the wav in vdub should not be a problem.

[SLK001]

What was the sample rate of the AVI audio?

[Taeranmoondance]

Heya !
It is best if I give you all the details:

1 - Original AVI is 1:32:34 ( 5554 secs ), framerate is 24 fps
2 - I stripped the audio from the 24 fps AVI, length of WAV is still 1:32:34
3 - I converted the video using VDub from 24 to 23.976 fps. Length of video becomes 1:32:40
4 - I converted the video to MPEG2 DVD format, using CCE, and performed a Pulldown, framerate becomes 29.97, length is now 0:59:58 ( 3598 secs )
5 - I use Goldwave to speed the sound up, using Time Warp ( 5554 / 3598 * 100 = 154.37% )
6 - I convert WAV to AC3 using AC3Machine
7 - I used TMPGEnc DVD Author to author.

RESULT = Video plays in length 59:58, and sound is very fast.

What am I doing wrong here, friends ? You see, I have made movies by joining 23.976 sound, with 29.97 pulled down videos, and they work, by I wanted to do things as correcly as possible. And the fact that the video is in a different framerate than usual is what lead me to ask for help.

If you need further info, please tell me.

Many thanks for the attention, I hope this serves others as well.

Live Long And Prosper

[bugster]

Heya !
It is best if I give you all the details:

3 - I converted the video using VDub from 24 to 23.976 fps. Length of video becomes 1:32:40

4 - I converted the video to MPEG2 DVD format, using CCE, and performed a Pulldown, framerate becomes 29.97, length is now 0:59:58 ( 3598 secs )

Thats not quite right is it! The video should be the same length AFTER pulldown as before. I think what you did is take your 23.97fps avi and encode to mpeg-2 as 29.97fps, hence the change in length.

What you should do is encode with CCE as 23.976fps (match the source exactly) to give you an .m2v file of 1:32.40. Then use pulldown.exe on it. This is a command line tool but I believe there is now a GUI available for it. The length of the video should not change, it simply adds some flags to the video stream that tells the decoder which fileds to repeat to obtain a playback rate of 29.97fps. So the length of the audio needs to be adjusted to match this.

[Taeranmoondance]

Ah !

So the problem begins with me not making the conversion to MPEG2 correctly. If I got it right ( and it makes perfect logic ), I should get a video just slightly slower than the original, and the audio should only be slowed like 1% or something like that.

So, if i understood right, my problem is really on the CCE conversion, and I never noticed it until now.
What seems to be happening is that CCE is speeding the video to 29.97.

Here is the AVISynth script for that movie:

avisource("E:\DVD\cobra\cobra.avi")
LanczosResize(720,398)
AddBorders(0,41,0,41)
ConvertToYUY2()

Is there something missing ?

Sorry to be such a pain, but I would like to get this right once and for all.

Live Long And Prosper

[bugster]

Ah !

So the problem begins with me not making the conversion to MPEG2 correctly. If I got it right ( and it makes perfect logic ), I should get a video just slightly slower than the original, and the audio should only be slowed like 1% or something like that.


Live Long And Prosper

Thats right.

I don't use avisynth/cce myself but that script doesn't seem to mention framerate. I would have thought the framerate was set in CCE. Set it to 23.97fps

[FulciLives]

Ah !

So the problem begins with me not making the conversion to MPEG2 correctly. If I got it right ( and it makes perfect logic ), I should get a video just slightly slower than the original, and the audio should only be slowed like 1% or something like that.

So, if i understood right, my problem is really on the CCE conversion, and I never noticed it until now.
What seems to be happening is that CCE is speeding the video to 29.97.

Here is the AVISynth script for that movie:

avisource("E:\DVD\cobra\cobra.avi")
LanczosResize(720,398)
AddBorders(0,41,0,41)
ConvertToYUY2()

Is there something missing ?

Sorry to be such a pain, but I would like to get this right once and for all.

Live Long And Prosper

You can use the original AVI that has a 24.000fps and use the following script:

avisource("E:\DVD\cobra\cobra.avi")
LanczosResize(720,398)
AddBorders(0,41,0,41)
AssumeFPS(23.976)
ConvertToYUY2()

BTW I think most AVI files (I am assuming we are talking a MPEG-4 DivX or Xvid here) are already YUV aka YUY2 so I don't think you really need that last line in the script.

- John "FulciLives" Coleman

*** EDIT ***
I just noticed that you have AddBorders of 41 on the top and bottom and that doesn't sound right to me. Are you sure that your resize to 720x398 is correct?