NTSC Timing To PAL - Any Easy Way?

[DeathStalker77]

I have an NTSC track that runs 1:29:40 that I would like to match up with PAL video that runs 1:28:05. I know I can use Change Speed in Audacity, but I don't believe that is an accurate reflection of NTSC to PAL. I could also convert it with TMPGEnc, but TMPGEnc retains the same duration even with standards conversion. Admittedly, I have not done the math, but I believe that the lengths should match up when changed from 29.970fps to 25fps.

Any suggestions?

Many thanks!

[manono]

Admittedly, I have not done the math, but I believe that the lengths should match up when changed from 29.970fps to 25fps.

No, assuming it's a movie it should match up with 23.976fps to 25fps. No one (properly) converts 29.97fps to 25fps if it's film based. Assuming it's a movie, if converted by speeding it up, the resulting PAL length should be something like 1:26:00. Since it's nowhere near that I can assume either the PAL version has extra scenes in it and the audio will never match up no matter what you do, or it was converted to PAL using a different method, perhaps with less content.

A short sample of the PAL source, one with steady movement, 10 seconds or so, can easily establish how the conversion was done.

[DeathStalker77]

Ok, if I can't adjust the audio to the video, can I match the video to the audio by converting it (maybe using Drop Frame?)

[manono]

It's got nothing to do with drop frame, which isn't used in PAL anyway. Drop frame or not will only account for about a 6 second difference in length for that movie (30fps .vs 29.97fps). You can go ahead and stretch the audio in audacity to make it the same length as the PAL version, but my guess is that at some point it's going to go way off all of a sudden when added to the PAL version. And if for DVD that will be a lot easier than stretching the video.

[DeathStalker77]

The PAL video is 25fps, the audio is from an NTSC source at 29.970. I have tried stretching it with Audacity and it does not work.

[manono]

I already told you it wouldn't work. No PAL DVD is converted from 29.97fps to 25fps by slowing it down, as you did with the audio. It'll make movement way too slow.

More about drop-frame. I don't know how you got the video length but some players (PowerDVD, for example) and apps will give you the time using non-drop frame timing (30fps). If you got a 30fps length, then it's about 6 seconds shorter than it really is.

[AlanHK]

In Audacity, load the audio from the PAL version first.
Don't touch it, use it as a timeline.

Then import a new track from the NTSC one.

Zoom in to the start and use the "Time shift" tool to slide the NTSC track so some obvious sound aligns.
Then go to the end and see if they're in sync. If not, note the exact time of some other sharp sound in both tracks.
Use the "Change tempo" effect to stretch the NTSC track to the required length
-- Select the track from the start to the sharp sound, then put in the exact time of the sound in the PAL track. Copy the "Percent change" shown. Then cancel. Select the entire track and open "Change tempo" again, paste in the percentage, and "OK".

The two endpoints at least will now be aligned. Jump around the track and see if it is in sync all the way through, If not you'll have to cut and move segments to match different edits

When satisfied, select the new track and "Export Selection" and choose your format.