23.976 encoding

[joshuaindi169]

hi can somebody please help me i am converting a .avi file.
i have checked and deleted the bad frames using virtualdubmpfreeze.
i have extracted the audio using goldwave.
when i use tmpgenc to convert the dvd plays great and then begins to lip synch i am using the ntsc template however the fps is 29.97 however virtualdub reports the fps as 23.976.
i think this is the problem can somebody please help and advise me how i can convert a 23.976 .avi so that i can use tmpgenc or is there another way.

[lpn1160]

first off, cutting out bad frames may also cause an audio synch problem.
Having said that, What I would try is this: When converting with tmpg keep the same frame rate (23.976). Then run your .m2v file thru pulldown.exe what this does is just change the fps flag and instructs your dvd player to preform a soft telecine. plus the fact that no dvd authoring program will accept 23.976fps files you must add the 2:3 flags with pulldown

get pulldown here--> http://www.inwards.com/inwards/?id=36

[joshuaindi169]

hey thanks for that.
i have removed bad frames before without synch problems but never on a 23.976fps .avi.
you sound as if you know what you are doing with this type of conversion but may i check;
i load the .avi into tmpgenc using a dvd ntsc 16:9 template then the resulting m2v file i run through pulldown.exe is this using a command line for instance "pulldown.exe movie.m2v"
then there should be no synch.

[lpn1160]

http://guiguy.wminds.com/downloads/pulldownbatchfe/
This is where you can get a GUI for pulldown, (yes pulldown by it's self is a command line tool)
I hope so, because audio synch problems can be very difficult to correct.
If you search this site for guides on each step you need to do you'll find solutions for any problems that arise

[sterno]

i am using the ntsc template however the fps is 29.97 however virtualdub reports the fps as 23.976.

You should be using an NTSCFilm template for a 23.97fps source, not the NTSC template. That will keep the video at 23.97fps and set the pulldown flags so that a DVD player will know how to play it. Since tmpgenc takes care of that you won't need to use pulldown.exe.

If you encoded with the NTSC template your MPEG is already at 29.97fps (tmpgenc changed the frame rate for you) and you should not use pulldown. tmpgenc's built-in frame rate conversion isn't that good, it could be the cause of your sync problem.

[joshuaindi169]

sterno you advised that i do not need to run pulldown as tmpgenc allready does it however my movie is now out of synch about 40 minutes in is there anything i can do to correct this.

[joshuaindi169]

just been thinking
if the audio only goes out of synch about half way through the movie could i not split the original .avi into 5 or 6 separate avi's then encode separatly then auth them.
or am i just being daft.
i am really struggling here and am at the stage of giving up anybody got any ideas.

[sterno]

If you encode using the NTSC template, you don't need to run pulldown because the NTSC template changes the frame rate to 29.97fps and you only need to set the pulldown flag for 23.97fps material.

If you encode using the NTSCFilm template, it defaults to setting the pulldown flags for you so you shouldn't need to run pulldown on it. You would have had to change a setting to disable 3:2 pulldown, if you just load the template it's set correctly.

Sync problems are often caused by the source material. What I've seen is that sometimes a few bad frames can throw the audio off from that point on, even if you delete the audio to match those frames. The AVI file plays properly and syncs up again by the next keyframe, but when the audio and video are seperated it can't do that.

[joshuaindi169]

thanks sterno but can you advise what i should be doing to correct (if possible) the lip synch.

[pijetro]

How about the original .AVI. Is it in synch?? IF the answer is yes, then how about the audio source?? Is it 41000khz or 48000khz. If it's 41000khz, then resample it with Vdub or CoolEdit..

I guess that's the first thing to look for....

good luck!!!!!

[sterno]

The last time I tried to fix a sync problem caused by problems in the AVI file I decided it wasn't worth the trouble. Based on what I found before I quit, here are some suggestions:

Try extracting the audio in virtualdub instead of goldwave. Save the audio after scanning for bad frames. With luck, the audio stream will be intact enough that VirtualDub will be able to save a wav file that matches the video stream.

If that doesn't work, try cutting the video file apart around the bad frames. Hopefully you'll be able to put all the pieces together and have most or all of it be in sync.

[pijetro]

Actually, to add another step to your suggestion, after checking for bad frames, what I do is 1) Save the .Wav, 2) Save the .AVI without audio (meaning tick the no audio), 3) Remux the audio and silent video, and finally 4) Recheck for synch.....

Good luck!!!!!