Modding a PAL DVD player to 24fps?

[tenebrenz]

This is purely theoretical at this stage but I have wondered a few times whether it would be possible to mod a dvd player to play PAL discs at 24fps instead of 25 thus allowing me to watch the movie at it's original speed and with the sound at correct pitch.
Would it be possible to underclock the whole system to allow this, and if it were possible would it be likely that many TV would cope with a signal 4% out of spec?

[Doom9]

well.. if it's a software based open source player then the answer is yes, otherwise no. But some commercial players already have a stretching feature that allows you to watch PAL movies at a speed (and thus audio pitch) equivalent to the original.

[bugsy_pal]

Hello Doom9,

I was very interested in your comment re the commercial players that can adjust for the 4% PAL speedup - as an Australian living with the PAL system, I have been bothered by the PAL sppedup issue on DVDs for a while - it's particularly annoying on music discs, where the change in pitch is very noticeable.

I'm aware that WinDVD (and probably some other software players) can correct the 4% speedup (the "PAL Truspeed" feature in WinDVD).

Can you advise any hardware DVD players which can do this correction now? It doesn't matter of they are only available in certain locations - it would just be good to know which brands/models to look out for. I did a bit of a search on the web via Google but couldn't identify any players with PAL speed correction.

Regards,
bugsy

[SeeMoreDigital]

Some years ago I found a cheapo karaoke DVD player that could do this!

I don't know weather this feature was by accident or by design. Never the less it worked.

Maybe other karaoke DVD players can do the same!


Cheers

[bugsy_pal]

SeeMore,

Can you tell me what make of DVD player it was that had this feature? Did the feature have a specific name?

The 4% PAL speedup really irks me - sure, I'll save a few minutes when I watch a movie, but I don't like the thought that everything is at the wrong pitch. I know for sure that hifi freaks would have convulsions at the thought that their expensive turntables or CD players were running 4% faster than they should.

I guess another question is: if there are technical corrections that can be made to get rid of the 4% PAL speedup, why aren't they universally done on all new DVD players? Are there problems or compromises in sound or picture that have to be made in order to correct the speedup?

Not knowing how they could do on-the-fly correction, I don't know what impact it would have on the picture etc. I can say that WinDVD's TruSspeed adjustment seems to have no adverse impact of the presentation of PAL discs on my PC.

[E-Male]

be carefull, you never know which pal dvds have corrected pitch

[avih]

well, that's a tough question, since if you're gonna slow down your pal dvd to 24 fps, it won't be synched to your tv set (which is 25fps or 50fields/sec). the best option would probably be to try and play it in ntsc mode (23.967 iirc), and have your tv-set in ntsc mode (if supported). otherwise, playing 24fps on a pal tv would be horrible...

[E-Male]

are there any (not so old) TVs that can't play NTSC?

[scharfis_brain]

there are PAL DVDs out there that do not have a PAL speedup...

either live with 2 stutters per second OR with lots of fieldblending

(the 2nd is the more common and more weird case)

[bugsy_pal]

All very good points... I don't know which Pal DVDs would have been pitch corrected, but I don't think there are that many. I think there are a plenty of TVs out there (at least in AUstralia) that won't play NTSC (there was a trend some years ago for VHS players to be able to output a picture from an NTSC tape on PAL TVs).

I must confess to not understanding quite what you mean by 2 stutters per second or fieldblending - are these the consequences of PAL speed adjustment? Or are you referring to judder on NTSC DVDs? It would be nice if I could just select which mode I view a disc in - but I doubt it's gonna be that simple.

That's why I was curious about the players that correct for the speedup - if WinDVD can do it, why can't a hardware player do it successfully?

[SeeMoreDigital]

Originally posted by bugsy_pal
SeeMore,

Can you tell me what make of DVD player it was that had this feature? Did the feature have a specific name? Unfortunately I can't. It was brought in for modification so a customer could use it on an exhibition stand.

But like the rest of the guys here have said, many of todays PAL movie DVD's are now telecined to accurately display 25fps content.

With respect to music DVD's I would have thought most of these are shot straight to video. And therefore are most likely to be either 25fps or 30fps interlaced anyway!

That said, there's no denying that some of these DVD's are worse than others.

Cheers

[bugsy_pal]

Thanks again,

Good points - I recently paid through the nose to get the NTSC version of Pink Floyd's "Live in Pompeii", where I could have had the PAL version for half the price. The PAL image is probably better (although there's no guarantee about that), but given the age of the film, I thought that a transfer from film at the correct speed was worth the money.

I will keep searching for a hardware solution to the PAL speedup issue.