PAL to NTSC conversion, weird sound problems

[wfn1]

Hello,

I'm trying to convert "Le Peuple Migrateur" DVD9 from PAL to NTSC and I ran into the following problem: the resulting DVD-R has a problem playing in my standalone Pioneer DV-525 / C503. It starts playing, and everything looks good till the soundtrack kicks in. Then it sounds like a short buzz and then the whole picture freezes. I can still skip around the move using << & >> keys or navigate the chapters but as soon as it starts playing there's this short buzzing and it freezes again.

I converted the video with CCE 2.5 via avisynth 2.07 wrapper. AssumeFPS + Bicubic resize. The resulting video looks just fine at 23.976fps. 720x480 res. The audio was converted via besweet 1.4 in ac3machine .41 using the frame rate conversion from 25000 to 23976. Also if it matters at all the soundtrack is DD 5.1. The project was authored in Scenarist 2.6 and did not have any errors. The resulting DVD plays from the hard drive via PowerDVD XP without any problems with sound in sync and all. I do hear a bit of crackling in the transcoded soundtrack but I can live with that. What could be the problem?

Thanks for any suggestions.

[sakism]

I can't tell you the solution to your problem but I can tell you what I've done to make several trailer VOB from PAL to NTSC:

I demuxed the VOB with VobEdit to m2v and ac3 files.
I use TMPGenc to convert the m2v file from PAL to NTSC in DVD format.
I do nothing to the ac3 file.
Then import audio and movie into Scenarist project and it came up a perfect NTSC DVD disk.

Maybe you'll see some short of crackling in the picture but the sound is perfect.


I hope this helped you.

[wfn1]

thanks for the suggestion.. I'm thinking, if I leave the AC3 as is wouldn't the sound run faster and out of sync since it is syncronised with the 25fps PAL video rather than 23.976fps NTSC video?

I was also thinking that I could use HeadAC3he to split my 5.1 track into 6 .wav files, do the stretching and pitch correction in Prosoniq TimeFactory and then re-encode using Scenarit's built in AC3 encoder.

I would like to avoid that if at all possible as it seems like too much work.

[wfn1]

I just tried your suggestion to keep the ac3 as is and as I expected the audio is out of sync with the video. Since PAL is faster the audio is ahead of the video.

Any more suggestions?

[sakism]

You're right about the sync of audio/video ONLY if you try to remux them (let's say with IfoEdit).
What I told you before is that you leave Scenarist to do the multiplexing (and believe me, he's doing it good ;) )

No matter how hard I tryed, I never made a good NTSC DVD out of a PAL with ordinary tools. Only Scenarist makes it possible :p
It makes a perfect sync of audio/video.

So try one more time not to make anything to the audio, convert the video and import them into Scenarist. That's the only way I know :cool:

[wfn1]

well, i am using scenarist to author the project. it does not do anything to the soundtrack when building so the audio stays faster than the video.

like i said i extracted the .vobs with dvd-decrypter, served with dvd2avi and wrapped with avisynth for video encode in CCE. If I do nothing to the .ac3 the speed of the video is not going to match the .ac3. It's 23.97 frames for the video and the ac3 is made to sync with 25fps video. Scenarist does not magically make the .ac3 sync with the video.

[wfn1]

Here's what I tried:

I made a 6 channel .wav via BeSweet (latest beta). The resulting file plays just fine and sounds absolutely perfect. Than my original plan was to stretch the .wav via Prosoniq TimeFactory using a factor of 104.270937604% (25.00/23.976*100) and re-encode it in Sonic Foundry Soft Encode or Scenarist's built in AC3 encoder. But after the TimeFactory went through it's motions (I selected polyphonic-best) I ended up with a file that was half as long as the original 6ch .wav and sounded like garbage, you cant distinguish anything it sounds like noise. The resulting .wav still reports 48khz 6ch but it's unusable. My thinking is that TimeFactory cannot correctly process 6 channel .wav files.

So my next step is to use BeSweet to convert into 6 separate mono waves and try to process them in TimeFactory that way. Please let me know if you have any other ideas or if my logic is flawed.

Another thing is, I'm not sure if this thread needs to be moved into Audio encoding... might be more appropriate at this point.

Mods?

[sakism]

I'm realy confused.
You have absolutely right about the sound being out of sync but I still don't get it.
I have several trailers in PAL and all I do is convert the movie and do nothing to the sound. In the end they rock.

The sync loss you got, it's from the beginning or later on? Because my biggest trailer is 10 min long. I didn't try to convert a movie. Maybe if I try it on a movie, after some time I'll have the same problem. :confused:

[wfn1]

No, the sync loss is from the very beginning. The video plays at 23.976 fps while the audio is synched for 25 fps, therefore the audio plays faster right away. I have no idea how you got PAL audio to match NTSC video perfectly without any adjustments. From everything I've read and tested myself it's absolutely obvious to me that I have to stretch the audio to match with the converted video. The only question is which method is the least painless and provides acceptable quality.

On the other hand I've grown quite accustomed to learning new and rather complicated software pieces in the course of my DVD backup career so I'm not expecting a miracle.

Cheers.

[sakism]

Now I remember something I've done:
I used BeSweet to change (in some trailers not all of them) the kbps from 384 to 448 on some ac3 files. Just try it. You don't have nothing to lose. Maybe this helps. :confused:

[wfn1]

well, my idea with using prosoniq timefactory for stretching didnt work... no matter what i do timefactory does not want to process the .wav files properly. it just stops half way through the file.

i made 6 mono .wav files in besweet and tried opening them one by one or as a batch in timefactory and do a stretch of 104.27094% but i get a 48 minute file instead of a 94 minute one. something is wrong.. well i guess i'm gonna have to use something different this time.

[wfn1]

well, i finally finished this project. Here's what I had to do to get the sound right:

1) Convert the original PAL 5.1 DD 384kbps .ac3 to 6 mono .wav files via besweet/azid

2) determine the actual video framerate with vdub (load video + any mono .wav and hit Ctrl+R, turned out to be 25.000 fps on the dot in my case)

3) stretch all 6 .wav files in cooledit 2000 (resample + hi precision, ratio of 104.271, you may have a different ratio depending on what number you get in vdub. essentially you do vdub fps / 23.976 * 100)

4) re-encode the resulting .wav files in soft encode 5.1 back to 384kbps .ac3 5.1 DD

5) reauthor w/ scenarist

step 5 doesn't matter, i'm sure you can re-author with your favorite package just fine.

the worst part of this method is that it takes about an hour to stretch each mono .wav in cooledit 2k and then another hour to re-encode it back with soft encode. on the brighter side of things, the audio turns out quite good this way (better be good for 7 hours worth audio work)

well, here we go...

i'm still disappointed that prosoniq timefactory didn't work because supposedly the quality is excellent but what can you do..

cheers.

[DIggedy]

determine the actual video framerate with vdub (load video + any mono .wav and hit Ctrl+R, turned out to be 25.000 fps on the dot in my case)


The framerate for PAL DVD is always 25fps without exception.

[wfn1]

not really, there are small variations (+- .09 frame). just load your .m2v or .vob in power dvd and click 'show information' you'll see that the frame rate varies slightly throughout the movie.