Question about PAL & NTSC ripping and re-authoring

[Jack_Dante]

OK, I understand that PAL format DVDs generally have a shorter run time to their NTSC counterparts owing to the fact it runs at 25fps, whereas NTSC runs at 24.

Now this may seem like an odd question, but if I were to rip an NTSC format disc into MPEG format then re-encode and burn it to disc in PAL format, would the run time be the same or shorter?

[jman98]

Shorter. And note that you'll also have to convert the audio and consider possibly changing the pitch as a 4% speedup in audio can be a noticeable change if you are familiar with the normal sound of the speakers and any music therein. I've got a UK DVD release of the 1st season of Futurama where they did not do pitch correction and it's very noticeable how the audio is faster. Everyone's voice is somewhat higher than normal.

I understand that this question may be more to satisfy curiosity and increase knowledge than to actually learn how to do this, but I will point out that such conversions are almost never necessary in PAL land. The vast majority of DVD players and TVs sold in PAL countries are capable of doing something sensible with NTSC video input.

[Jack_Dante]

I understand that this question may be more to satisfy curiosity and increase knowledge than to actually learn how to do this, but I will point out that such conversions are almost never necessary in PAL land. The vast majority of DVD players and TVs sold in PAL countries are capable of doing something sensible with NTSC video input.

Thanks for that, the reason for my question was that I purchased a DVD from Europe, which is in the PAL format, however its run time matches the US NTSC release.

I rather get the impression they just ported over the US disc (with this being a rather obscure film) and changed it to PAL format, so was wondering how they managed to preserve the running time considering it should now be shorter?

[lordsmurf]

Then it was made with frame duping, not speed-up.

[Jack_Dante]

Then it was made with frame duping, not speed-up.

Could you explain frame duping to a novice like myself?

[manono]

If the PAL time is the same, it's more likely to be done using field-blending than frame (or field) duplicating. I've seen both, but field-blending is way more common.

The preferred way is the PAL speedup since you get clear and smooth playing video.

When he says frame-duping, a literal explanation is that one frame every second is duplicated to go from 24fps to 25fps. More common is to duplicate a field every half second (less obviously jerky playing). Both are fairly rare, though, but both keep the original length and the original audio can be used so no pitch problems.

[Jack_Dante]

Thanks to all who replied, that has cleared up a few questions I had.