DivX PAL --> NTSC DVD (Audio Issues)

[dpopeney]

I have a DixV PAL video that I want to write to a NTSC DVD format. I have tried many of the guides and have learned a lot. However, after a week of banging my head against the wall trying to get the audio to sync up, I've come here for some advice.

Source
Video: 416x320, 25fps, DivX 5, 176913 frames
Audio: 96 kb/s, MP3 CBR, 24000Hz, 176121 frames

Playing the video in WMP the audio matches up fine. I've followed all the guides by ripping the audio from VirtualDub and making it into a PCM wav file. I've tried converted the wav file to 29.97 fps using Goldwave, by the Time Warp effect, and I've also tried BeeSweet using the handy fps conversion option.

For the video I followed the guide for converting PAL->NTSC using TMPGenc. changing to 720x480, 29.97 fps, MPEG-2, 2Pass VBR, 4000avg bit rate.

I went to try the VirtualDub frame rate conversion and noticed that under the Video..Frame Rate option, there was a choice to convert the video to match up with the audio (25.047 fps). I'm think that this is the source of my problems...that the video frame number doesnt match the audio frame number. But I have no clue how to proceed next!

Any advice would be greatly appreciated!! I know that audio sync questions get asked a lot here and I tried to do as much searching and guide reading as possible, but couldnt find the exact solution to this problem.

[dafreak]

I think you're on the right track.

when you load the divx file into goldwave, you need to resample to 48000 mhz, and then time warp to 29.97 fps. make sure you set the bitrate to at least 192 kb/s.

load the ntsc dvd template into tmpgenc. click on setting. on the advanced tab, put a check next to do not frame rate conversion.

multiplex your new audio and new video.

[dpopeney]

with the audio, i did that. I ripped the audio in VDub and converted it to 48kHz at the same time, also made it 8 bits and tried 16 bits. and the bite rate was 1536 kb/s or sometihng like that

I also did your suggestion with the check box, and that didnt work.

Seems like either way I go when i convert it, it will alway be out of sync since the source audio and video # of frames dont match up. but some how, in the original avi they sync. very strange

[johns0]

The best way to get the audio to match is resample to 48khz and save as wave,then use besweet and choose framerate pal to ntsc 25fps to 23.976.Also encode the video at 23.976 and check in settings/advanced/ do not convert framerate and encode mode set it to 3:2 pulldown when playback.Also if the audio is a bit out of sync after you can mux with bbmeg and set the delay you need.With the resolution of the divx file you have its best to encode at 352x480.

[spidey]

Also search for several posts by DJRumpy pertaingin to this all. EH has explained it extensively.

[dpopeney]

great! thanks a lot for your replies. I'll read through DJRumpy's posts and see if that anwswers the problem

The 3:2 pulldown option is something I havn't tried. So I hope that does the trick. Thanks again for the help!

[dpopeney]

Finally got this file to sync up after trying many things. Posting what I did in case it helps anyone else out.

Video (using TMPGEnc)
Source: PAL DivX 5 AVI video 416x320, 25fps
Convert to:

• - MPEG-2
  - 720x480
  - 23.976 FPS (29.97 fps internal) --> "do not convert framerate" option check under settings/advanced and Encode Mode = "3:2 pulldown"
  - 2Pass VBR
  - 4500avg bit rate.

Audio
Opened AVI in VirtualDub. Under the menu, Video..Frame Rate, I noticed that there was an option to sync the video with the audio and the FPS listed was 25.047 and not 25.000 FPS (the video source FPS). This told me that naturally there would be an audio sync problem since the audio and video werent natually the same FPS (the codec must sync the 2 durnig playback, since the source AVI file audio and video synced perfect). With this in mind I proceeded with the normal method of ripping and converting the audio

• - Used VirtualDub to save the wav file of the video as described in many of the guides on this site. Options: Uncompressed PCM, Full Processing mode, No conversion to 48000 MHz
  
  - Used GoldWave to convert PAL to NTSC time frame. Since I was going from 25 FPS to 23.976 FPS I needed to shrink the audio.
  
  - Use the Time Warp option and enter the percent difference of the time I wanted to shrink to --> (23.976/25.0)*100% = 95.904%
  
  - I then resampled the audio to the DVD standard, 48000 MHz (Using the Resample option). Dont think it matters if you resample before the time strech or after. Didnt seem to make any difference for me.

After combining the files using TPMGEnc DVD Author and outputting the DVD, I noticed the audio would gradually go out of sync over time (The video was ahead of the audio by a second or 2 one hour into the movie). This told me that the strech that I did before was not the correct amount and that I would need to decrease my strech factor. This is the hard part, I really just messsed around with the shrink factor till the audio and video matched up. Dumb luck would have it that 95.9% worked out the best (the first number I tried too! :P )


So if theres a lesson to be learned from all of this to convert PAL DivX AVI to NTSC DVD, it would have to be these points...

• Going from PAL (25.000 FPS) -> NTSC DVD use the 23.976 FPS (29.97 fps internal) option by choosing "do not convert framerate" option check under settings/advanced and Encode Mode = "3:2 pulldown"

• Get to know your audio, make sure the audio and video have the same frame rate using VirtualDub (menu Video..Frame Rate)

• If loss of audio sync over time happens, tweak the strech factor untill it syncs. This is a trial and error process and may take a lot of time to get right.

• This process is a pain in the ass and takes hours of reading guides, converting and re-converting, and re-converting. Make sure you really want to get wrapped up in the maddness of conversion. But it's really rewarding if you get everything to work and sync up!

Good Luck! 8)

[Gideon25]

BeSweet has an option to convert the framerates and it works VERY well. I use dvd2svcd (with CCE as the video encoder). Check out my avi DivX/Xvid PAL--->NTSC one process conversion:
https://www.videohelp.com/forum/viewtopic.php?t=212203

Ignore the 2ndpost regarding batch stuff as I have to edit it to reflect the changes the author made with the latest release of D2sRoba. You have to learn how to use D2Sroba and dvd2svcd. Once you learn how to use those then its as simple as ediing the files I spoke of in the post. After that you simply start D2sroba, use it to lanch dvd2svcd, load up your avi, and click convert and EVERYTHING is automated from the framerate conversion to pulldown to the audio conversion. You end up with a multiplexed mpg IN SYNC ready to burn. I have done about thirty 45 minute episodes so far and ALL of them have stayed in perfect sync. In short this method (which can be modified to suit ones special avisynth needs and so forth)is the PERFECT method in its automation, and its a major time saver. Of course that means you have to learn how to use D2Sroba and dvd2svcd (Doom9 forums).

Of course in THIS case you had a funky divx file where audio was considerably off from the video framerate. Most of mine that I have seen that were off were only off by like .010 or less of a frame. What a pain, but generally pal->NTSC is not so difficult

[Skynet107]

I don't know about anyone else but I always encode the video first when doing a frame rate conversion. They I take the exact time of the video file and "time warp" the audio file to exactly match the video.

BeSweet also works well most of the time but not always.