NTSC-->PAL audio (29.97 -->25)

[romi7519]

Hi all!

I was hoping someone can guide me on how to go about converting ac3 audio from an NTSC source to PAL pls..

I have tried a few things but the results are poor or out of sync.

Any help/pointers appreciated!

Cheers!

PS: What is the exact amount of speedup?

[mh2360]

Is the NTSC Video source 23.976 or 29.97 frames per second?

[romi7519]

its 29.97 mate

[manono]

Assuming it's a movie, you want to speed it up from 23.976->25fps. BeSweet has a preset for this. 25/23.976=1.04271.

[romi7519]

there is also a delay on this track, should i add the delay 1st usind ac3delaycorrector and then do the conversion?

also i noticed. the video length is 2:25:09 and the audio is 2:25:18 untouched.

[manono]

You'll have to account for the delay at some point. Might as well get it out of the way in the beginning. Depending on how you do the audio conversion, the audio program may be able to take care of the delay on its own. BeSweet can.

the video length is 2:25:09 and the audio is 2:25:18 untouched.

So what? One or the other may not be accurate. And it's not uncommon for them to have different lengths. If you're converting the audio from 23.976->25fps, you had better do the same with the video, if you want them to remain in-synch.

[mats.hogberg]

Your best bet is not to do any frame rate (or TV system) conversion at all, since most PAL equipment handles NTSC material just fine.

/Mats

[romi7519]

@ manono

yes im doing the same for video too.

ps: can u take a look at the dvd9 to dvd5 thread pls?

cheers!

[romi7519]

Your best bet is not to do any frame rate (or TV system) conversion at all, since most PAL equipment handles NTSC material just fine.

/Mats

im encoding a pal master to xvid.

[mats.hogberg]

im encoding a pal master to xvid.

converting ac3 audio from an NTSC source to PAL

Huh? Which is it?
Since AVI/XviD is mostly for PC playback, there's even less reason to do any TV system conversion, since computers don't care at all about it.
Or do you have audio from an NTSC video that you want to use with PAL video?

/Mats

[romi7519]

im encoding a pal master to xvid.

converting ac3 audio from an NTSC source to PAL

Huh? Which is it?
Since AVI/XviD is mostly for PC playback, there's even less reason to do any TV system conversion, since computers don't care at all about it.
Or do you have audio from an NTSC video that you want to use with PAL video?

/Mats

the dvd has been field blended to ntsc from a pal source. it has a lot of ugly ghosting which is pretty bad when deinterlaced and left at 29.97fps hence the reason why im trying to return it to its original.

[manono]

the dvd has been field blended to ntsc from a pal source. it has a lot of ugly ghosting which is pretty bad when deinterlaced and left at 29.97fps hence the reason why im trying to return it to its original.

Geez, maybe you should have said that in the beginning. The unblended 24.975fps video will be exactly the same length as the original 29.97fps video. Nothing has to be done with the audio.

[romi7519]

^ yes, you're correct but I wanted to make it exactly 25fps.

also, i'm just experimenting a lot. trying to learn a few things here n there

[manono]

^ yes, you're correct but I wanted to make it exactly 25fps.

In that case, encode the video for 25fps and when done, run the MPV through DGPulldown with the Custom box ticked and set for 24.975->25.000. That way the video length remains unchanged, the video outputs at 25fps, and allows the use of the original, unchanged audio.

[romi7519]

^ wow! I didn't know that. that will help when I do mpeg2 encodes, but how to do it for XviD?

I doubt there is an equivalent of DGpulldown for mpeg4's or is there?

[manono]

Oh, this isn't for DVD? Then, no, there's no MPEG-4 equivalent. There's no reason you can't leave the AVI (if that's what you're going for) at 24.975. But, if you are, as you say, experimenting, then add an AssumeFPS(25) to the script and change the audio length.

You could still keep the original video length and the same audio and at the same time make it 25fps by adding a ChangeFPS(25) to the script. This will insert a duplicate frame about every 40 seconds (every 1000 frames) and make for a very slight stutter or jerk in the video. It may be noticeable and annoying to you. It may not be.

[romi7519]

OK, looks like I best stick to 24.975fps. I don't like jerky/stuttering playback at all.
Cheers everyone for the input but if anyone does come across an easy way to do it, pls post back.

[manono]

AssumeFPS(25) speeds it up very slightly, and provides for smooth playback. But it does require stretching the audio slightly to keep it in-synch.

[romi7519]

the prob here is that my demuxed files are of diff length. i used goldwave to stretch the audio but audio had gradual de-sync problem and near to the end, it was off by a couple of seconds.

I'm thinking of adding the delay, cutting the track to the exact length of the 29.97fps video and then doing the time warp again.

[manono]

I'm thinking of adding the delay, cutting the track to the exact length of the 29.97fps video and then doing the time warp again.

You're going about it the wrong way. Yes, delay it, but also stretch it by a factor of 1000/1001 (=24.975/25). You want he result to be .999 the length of the source. I don't know Goldwave, but there must be some kind of a percentage stretch available.

Or just leave it at 24.975fps.