DGPulldown and DVD Spec compliancy?

[Matthew]

This isn't really a question about DGPulldown per se, but rather what is does (i.e. I'm not suggesting DGPulldown is broken).

Some background information:
-I live in PAL land and have a Sony DVD player that supports NTSC (it says)
-When in the past I tried to play NTSC (film) material, the audio seemed to go off-pitch at times, perhaps like slo-mo. So I thought bugger that and stuck with converting to PAL (presto, problem solved).
-The DVD player also distorts the audio (pitch goes funny is part of it) with 48khz SVCDs (serves me right for not sticking to the spec).

Anyway, I decided to try DGPulldown for 23.976->25 to see if the jerkiness was a problem (on panning scenes). As it happens, it didn't irritate me much. But the audio stuttered here and there, which I think is due to the use of DGPulldown, especially given info above. No problems with the other 2 'normally' converted videos on the disc, which were part of the same set.

All this long-winded babble comes down to one question...is using flags to repeat field compliant with the dvd spec for anything other than 23.976->29.97?

[mpucoder]

Yes, fully compliant. If your player has a problem with it, it is the player's software that is at fault.

[scharfis_brain]

Yes, fully compliant.

Even for PAL?

[mpucoder]

Yes, even for PAL. The ability to pulldown is part of the mpeg video standard, not something specific to DVD. Mpeg-2 is very independant of television standards, in fact there is only one field (mostly ignored) that refers to a standard (sequence_display_extension).
To quote DVD Demystified 2nd edition P292
The actual coded picture rate in the MPEG-2 stream does not have to be exactly 24 or 30. Other coded picture rates or even varying rates will work, as long as the MPEG-2 repeat_first_field and top_field_first flags are set properly to produce either 25 or 29.97 fps display rates.

[scharfis_brain]

Thanks.
So I am on the right side, when doing my weird NTSC-Film -> PAL conversions with DGPulldown :)
(It is also useful to telecine 18 fps Super-8 Film to PAL :) )

[Kika]

If you choose the correct picture size - yes.
But you will get interlaced output, even on progressive source.

[scharfis_brain]

But you will get interlaced output, even on progressive source.

That's the reason, why I like it.

[Kika]

Strange world... :D

[Matthew]

Yes, fully compliant. If your player has a problem with it, it is the player's software that is at fault.

Thanks a lot, that's precisely what I wanted to know :)

It's a bit wobbly for Sony to have botched this up though. I wonder if many other PAL players exhibit issues.

[mic]

"It's a bit wobbly for Sony to have botched this up though. I wonder if many other PAL players exhibit issues."

FWIW, check out the hardware reports at videohelp.com -- seems the cheaper players (all those with the innards made by apex and such), do much better then the name brands.

[Kika]

My Denon DVD2910 does not have any problems with files like that... so i can't agree.
I only know two brands with problems: Sony and Phillips, maybe Panasonic (not checked)

[Matthew]

FWIW, check out the hardware reports at videohelp.com -- seems the cheaper players (all those with the innards made by apex and such), do much better then the name brands.

My understanding is that, as a general rule, this applies to breaches of the dvd spec, e.g. an Apex will be more likely to handle a 480 res DVD than a Sony. But I'm not going to blame a name brand player for not playing that - it's non spec, and there is a spec for a reason. The case at hand is of course a different kettle of fish.

[Kika]

Sorry, that's not the correct way to handle this, and this discussion is not about how to handle 480-Sporce, it's about the correct use of Pulldown-Flags. Using Pulldown-Flags is Part of the MPEG2-Specs - and DVD is using the MPEG-Specs!

[Matthew]

huh?

The point I was making is that the comments at VCD help about the cheap brands being "better" probably relate to non-spec DVDs, and hence cannot be applied to cases where the DVDs do meet the spec (such as this one).

[mic]

"FWIW, check out the hardware reports at videohelp.com -- seems the cheaper players (all those with the innards made by apex and such), do much better then the name brands."

:( Sorry -- just making a comment that compatibility is a problem, in response to Matthew's wondering about Sony -- It might be of use to some readers out there. Didn't mean to start any disagreements. And again FWIW, no offense intended to anyone, Matthew's original question IMHO was about playback problems, and how pulldown could/might apply.

That said, the DVD spec is rather large and all encompassing (& largely unpublished). Check out back issues, posts etc. for DV mag & one fellow in particular, a pro, has documented in some detail how compatibility issues cause problems as the one Matthew was talking about with his Sony and the audio on some discs. There are problems with different media, including CDs for SVCDs, and there are problems with players not complying with every detail of the spec. The latter is a problem with some commercial DVDs here in the US that fully comply with specs, yet are either unplayable or have features that don't work for many buyers. So it's really not just a matter of out of spec DVDs.

That said, & I do apologize for being off topic in this paragraph, as a consumer I really don't care about much more then value for my money. If one brand does something, and another is more expensive & doesn't, guess which one I'll buy? The company charging more has to convince me that extra change is doing more then helping add a room to some exec's chalet.

SVCDs using 48/16 ac3 should not really be a problem, and aren't on either of my standalone players, both with Apex ancestry. At any rate, as suggested earlier, please don't take my word for it, but see what folks have written about their experiences in the real world with hardware they purchased.

:thanks:

[Matthew]

mic you have nothing to apologise for, and there's no disagreements in this thread - I think :)

My remarks came from the belief that's it's not fair to judge name brand players compatibility with the spec with reference to their treatment of discs outside of the spec.

And as I've heard the comment "My Apex plays everything I throw at it", or a variant, quite a lot, from the sort of people who place SVCDs on DVDR, I assumed the comments to which you referred related largely to non-spec discs. To the extent that assumption was wrong, I deserve a slap :p

As an aside, compatibility isn't everything. Length of life and video quality are important too ;-)

[mic]

As an aside, compatibility isn't everything. Length of life and video quality are important too ;-)
Good Point

Only thing I'd add, & I can't quite figure out the wording, would be to slip in a plug for mpucoder's site, something about what to do with the money saved if they did go the Apex route. :D
:thanks: