OT: How does on the fly NTSC conversion compare to software conversion?

Laurence wrote on 1/19/2005, 7:09 PM
I've been thinking, but have no way to test it:

How does the built-in on-the-fly NTSC conversion on most PAL DVD players compare to the quality of NTSC footage converted to PAL with Vegas or some other conversion software? If you're starting with NTSC footage, is there enough difference to even bother converting formats? I know that on the two NTSC DVD players I've seen that can convert the other way (PAL discs on an NTSC TV), the results looked kind of jerky on pans, zooms and titles. Also, how consistant are these on-the-fly DVD player conversions? I know I put quite a bit of effort into converting and re-authoring DVDs for my tiny PAL audience. Is there enough difference in quality to warrent the effort?

Comments

jaegersing wrote on 1/19/2005, 10:00 PM
Hi Laurence. Playing NTSC discs on a PAL system may not be a full conversion. The link below has some info about PAL60 which is commonly used for this. Because there is no change of frame rate, converting in the DVD player should give smoother results than what you will probably get with most full conversions.

Richard Hunter

(EDIT - just trying to make this link clickable!)

All For MP3
Laurence wrote on 1/19/2005, 10:07 PM
Great link. Thanks. Has anyone seen this "PAL60" playback firsthand? How does it look? How does it compare to converted footage?
farss wrote on 1/19/2005, 10:29 PM
We play a lot of NTSC DVDs on our 'PAL' gear but it goes through the chain as NTSC, it's hardly a conversion!
I have one DVD that'll do a conversion if needed but the manual does point out that the results will be nowhere near as good as watching in native format.
Mostly all that's done is to shift the color burst so the TV will lock onto that, the frame rate doesn't bother most TVs these days and given that most gear in PAL land will play NTSC as NTSC and the TVs cope just fine I'd be inclined to just give your PAL viewers NTSC DVDs.
If they really need PAL then you can either do it in Vegas which does a pretty good job or have a pro dub house do it with broadcast grade equipment such as the Leitch box. If you've got a DSR-11 you can capture the PAL tape back no problemo.

Bob.
singapuree wrote on 1/20/2005, 1:35 AM
Most PAL DVD players play NTSC DVDs as PAL 60. This is where the framerate is kept as it is, as most UK TVs can auto sync on 60Hz, and the NTSC colour signal is changed to PAL. There are some DVD players notably the far east cheap brands that'll do real conversion but in those cases you see jerky motion on panning shots as one in six frames is dropped. A better way to convert NTSC to PAL, short of an expensive resampler, is as follows:

If the material is interlaced then split the frames into it's component fields. i.e. go from 30 fps to 60fps where each frame was originally a field. Then drop one in six of these fields and then recombine the fields to the new frames. This is different to dropping a complete frame because the time granularity is 1/60th of a second as opposed to 1/30th of a second. This method is described on the excellent http://forum.doom9.org where there is a wealth of information on DV editing, noise reduction and framerate conversion, etc, etc.
Laurence wrote on 1/20/2005, 5:18 AM
I'll check inot that method of conversion. From what I'm hearing so far, it sounds like I should just stick with NTSC DVD's. Most people in PAL countries will see the image comperable to what you do with an NTSC setup and possibly superior to a software conversion. Is that correct?
mbryant wrote on 1/20/2005, 6:56 AM
Yes. I'm in PAL-land, and have played numerous NTSC DVDs. My DVD player and plasma screen can do it both ways. Generally I have my DVD player setup for PAL, and when I play an NTSC disc it is PAL60. But if I think of it, I can change the player to output true NTSC. When I do this, I find the true NTSC picture to be a little bit better, but the difference is not significant.

Lots of people here buy NTSC discs e.g. of films, often they are released earlier, and sometimes cheaper...

I've also done conversions with Vegas (from PAL to NTSC), and you lose some quality here...

So in short, I agree, most of your PAL customers will find playing the NTSC disc as good or better than one converted to PAL. The only danger is if you get a customer in PAL-land who has a player that outputs true NTSC with an NTSC disc.. in this case if they have a PAL-only TV, they will get a black and white picture.

Mark