NTSC -> PAL conversion
in [UK Linux]
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From: Martin Gregorie on 20 Nov 2009 14:30 Is there any Linux application that can convert a US NTSC DVD to PAL or MPEG4? Apologies if this is a dumb question: I really don't understand video DVD formats. -- martin@ | Martin Gregorie gregorie. | Essex, UK org |
From: Tony Houghton on 20 Nov 2009 15:56 In <he6qop$rk4$1(a)localhost.localdomain>, Martin Gregorie <martin(a)address-in-sig.invalid> wrote: > Is there any Linux application that can convert a US NTSC DVD to PAL or > MPEG4? > > Apologies if this is a dumb question: I really don't understand video DVD > formats. The usual conversion tools such as mencoder can do it, but as Paul Martin implied, are you sure you need to? DVD players and TVs that can't do both NTSC and PAL are quite rare. I think you'll need to increase your understanding of the formats before you can manage it, because I'm not aware of a simple "NTSC to PAL wizard", you need to build up your own filter chain. The fundamental difference between NTSC and PAL DVD is that the former is 720x480 @ 30fps and the latter is 720x576 @ 50fps. Both are interlaced, but are usually mastered from 24fps progressive sources (film). A process called telecine or pull-down is used to convert film to NTSC (it's a bit too complicated to explain here, Wikipedia it). A player can detect this and reverse the process for a computer monitor or "24p" TV. For PAL the film is simply sped up slightly to play at 25fps instead of 24fps and both fields of each interlaced frame come from the same source frame. Clever audio processing can prevent the pitch from being altered when the sound is sped up. So to convert it you'd need to get mencoder or whatever to do inverse telecine (I think that's more or less automatic), scale up to 576 lines (not really necessary if you use MPEG4 as your output) without changing the aspect ratio and speed up to 25fps, resampling the sound. -- TH * http://www.realh.co.uk
From: Ivor Jones on 20 Nov 2009 16:03 On 20/11/09 20:56, Tony Houghton wrote: > In<he6qop$rk4$1(a)localhost.localdomain>, > Martin Gregorie<martin(a)address-in-sig.invalid> wrote: > >> Is there any Linux application that can convert a US NTSC DVD to PAL or >> MPEG4? >> >> Apologies if this is a dumb question: I really don't understand video DVD >> formats. > > The usual conversion tools such as mencoder can do it, but as Paul > Martin implied, are you sure you need to? DVD players and TVs that can't > do both NTSC and PAL are quite rare. I think you'll need to increase > your understanding of the formats before you can manage it, because I'm > not aware of a simple "NTSC to PAL wizard", you need to build up your > own filter chain. [snip] There's hardware to do it I think, ISTR Maplins sold a device to do it, or was it PAL to NTSC, I don't remember, worth asking. Ivor
From: Frank Peelo on 20 Nov 2009 17:08 Tony Houghton wrote: > In <he6qop$rk4$1(a)localhost.localdomain>, > Martin Gregorie <martin(a)address-in-sig.invalid> wrote: > >> Is there any Linux application that can convert a US NTSC DVD to PAL or >> MPEG4? >> >> Apologies if this is a dumb question: I really don't understand video DVD >> formats. > > The usual conversion tools such as mencoder can do it, but as Paul > Martin implied, are you sure you need to? DVD players and TVs that can't > do both NTSC and PAL are quite rare. I've got one. I got given a DVD from my brother in America for my birthday. It almost sort of played, but was in black & white. > I think you'll need to increase > your understanding of the formats before you can manage it, because I'm > not aware of a simple "NTSC to PAL wizard", you need to build up your > own filter chain. I tried to find a way to do this. I /think/ the closest I got was by copying it to the hard drive as an mpeg or avi or one of those things, then making a DVD with DeVeDe. But the result jerky... as you would sort of expect from what Tony Houghton said. Eventually came to the conclusion that it's not possible to convert the disc. So I just watched it on the computer. The seats are not as comfortable, but at least the film worked OK. Frank
From: Tony Houghton on 20 Nov 2009 17:34 In <7moibdF3gq51lU1(a)mid.individual.net>, Frank Peelo <f32pnospam(a)eircom.net> wrote: > Tony Houghton wrote: > >> I think you'll need to increase >> your understanding of the formats before you can manage it, because I'm >> not aware of a simple "NTSC to PAL wizard", you need to build up your >> own filter chain. > > I tried to find a way to do this. I /think/ the closest I got was by > copying it to the hard drive as an mpeg or avi or one of those things, > then making a DVD with DeVeDe. But the result jerky... as you would sort > of expect from what Tony Houghton said. It's probably trying to match find the nearest frame in the input to each frame in the output. If the source was progressive and DeVeDe applies inverse telecine it's not too bad, you just get a frame repeated once a second. If the source was interlaced or DeVeDe hasn't applied inverse telecine you'll get a much more horrible juddering. > Eventually came to the conclusion that it's not possible to convert the > disc. It isn't altogether impossible, but getting a really good (smooth and unblurred) conversion if the source was interlaced isn't really possible. -- TH * http://www.realh.co.uk
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