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Horrible PAL playback on HTPC/D-ILA  

post #1 of 6
Thread Starter 
After many years of reading about video formats, I think I fully understand how NTSC video works. I understand interlacing, 3:2 pulldown, etc. However, PAL eludes me.

Case in point, Buffy Season One DVDs are only available in region 2 PAL. It seems that "on paper" PAL is easier to work with, but I am getting terrible playback of PAL (region 2) discs on my HTPC. I have tried PowerDVD, WinDVD, and even the Apple DVD player on my G4. None of them play these discs correctly.

I'm assuming Buffy is shot on film at 24fps, editing and FX are done at 30fps (60 fields). Then this mixed up video is then converted to PAL at 25 fps (50 fields?). The discs were NOTencoded with any pulldown tags (ie they were encoded as pure video source).

WinDVD and PowerDVD both drop frames constantly, giving me an inconsistant framerate of much less than 20fps. Much worse in high motion scenes.

Apple DVD Player actually plays it back at an acceptable framerate but doesn't even attempt to eliminate interlacing, so I get interlace stripes all over the place.

So I decided to get down and dirty with this video, using an unnamed program on the Mac I ripped part of it to my HD, what I got was a mess. Normal interlacing mixed with strange multicolored interlacing. Sometimes the background frames would be perfectly non-interlaced but titles on top would be heavily interlaced, sometimes the opposite happened. No matter what I did, I was unable to extract anything close to progressive data. I've tried ripping at 24, 25 and 30fps, all to no avail.

I understand that PAL is sped up slightly. Could somebody please explain how footage survives the trip from 24 to 30 then back to 25? Ideally I would like to convert this back to it's original 24fps. How much do I need to slow it down, and how on earth do I de-interlace it? Neither Cleaner 5 or Adobe After Effects seem to understand a 2:2 pulldown.

Or even better, how I can get such a disc to playback well on my HTPC.

Thanks,

Jeremy

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D-ILA, HTPC, HDTV, Panamorph(?)
post #2 of 6
Jeremy -

Hi. Another Buffy fan!

I too have the R2 Season One Buffy set. I can't explain all the nuances but I think your major problem is that Buffy season 1 was video sourced, not film, and not that high quality transfer. I read that in a review somewhere.

If that's the case then a few things happen.

First, it is only 50 FPS for PAL not the 60 for NTSC.

Next, there is more work trying to deinterlace DVD video source than there is doing 2:2 pulldown for film sourced stuff. You are more apt to experience dropped frames.

Third, the players don't handle video source as well. I found I could play it more or less ok on P-DVD 3.0 but WinDVD gave a lot of weave artifacts.

Finally, there is a funny timing judder of some sort on my system which is probably again due to the 50 / 60 Hz difference.

Given all that I still sat down and watched the entire 12 episode set in only a few days, and immensely enjoyed them. http://www.avsforum.com/ubb/wink.gif

I was not a Buffy fan back in season 1 and had never seen some of the episodes before.

BTW, I also pre-ordered Season 2 R2 from Amazon-UK. IIRC season 2 was shot on film and was supposed to be much better quality and I think has 20 episodes. I think it's due out this month.

- Tom

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(This sentience has tree errors.)
post #3 of 6
Thread Starter 
Indeed... Buffy Rocks! (The show, not just the person - Joss Whedon is the MAN!).

Read this quote from SCIFI.com:

Noxon [buffy Executive Producer] also dropped that they're planning a fully musical episode. She explains, "It is an all-singing, all-dancing Buffy, with music written completely for the show by Joss. Because he doesn't have enough to do [laughs], what with seven or eight television shows on the air, or whatever he's got, and the comic books he writes and the movies, ... he decided he wanted to learn how to play the guitar and piano, and now he's composing incredible music."

But I digress...

From what I've heard, Buffy season 1 WAS shot on film, but only 16mm. And yes the transfer isn't all that great. But whoa, the packaging... Best DVD packaging I've ever seen.

So you had the best luck with P-DVD 3.0? What refresh rate was your video card set to? Theoretically shouldn't 50 be ideal? Or 75 (25 X 3)?

Jeremy

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D-ILA, HTPC, HDTV, Panamorph(?)
post #4 of 6
Jeremy,

Film doesn't have to make the trip to 30fps then 25 for PAL, or it shouldn't. If the studios decide to use the film tranfer when creating the PAL version, that conversion never takes place. If our transfer comes from NTSC's, them it'll be a mess for sure, with artifacts and softness easily noticed on any display larger than 32".

Here's what we European folks do when converting from film: we want 25 fps, but the source only gives us 24 fps. So, in any given 1 second time frame, we accelerate those 24 frames, so now they take less than 1 second to display. In the remaining interval, within this second, we add another frame, from the 24 that are in your NEXT second. This acceleration translates into something like a 4% shortening of the feature's length.


To your problem:

PAL has higher resolution at 720x576. This, and the fact that, as Tom said, video requires more processing power than 2:2, could be the cause;

if indeed Buffy was transferred to NTSC then PAL, it'll probably look bad (but this should have no effect on framerate);

have you tried forcing BOB (since there are no pulldown tags)?;

Finally, yes, theoretically it should be 50/75/100 Hz refresh.

Regards, RC
post #5 of 6
Jeremy -

Quote:
<font face="Verdana, Arial" size="2">Noxon [buffy Executive Producer] also dropped that they're planning a fully musical episode. She explains, "It is an all-singing, all-dancing Buffy, with music written completely for the show by Joss. Because he doesn't have enough to do [laughs], what with seven or eight television shows on the air, or whatever he's got, and the comic books he writes and the movies, ... he decided he wanted to learn how to play the guitar and piano, and now he's composing incredible music."</font>
I have mixed feelings about an all musical Buffy. http://www.avsforum.com/ubb/wink.gif

Quote:
<font face="Verdana, Arial" size="2">From what I've heard, Buffy season 1 WAS shot on film, but only 16mm. And yes the transfer isn't all that great. But whoa, the packaging... Best DVD packaging I've ever seen</font>
You are right on both counts. I misrembered what I'd read. Just went back and found the review at the very interesting Bullets&Babes site.

Which said:
Quote:
<font face="Verdana, Arial" size="2">
DVD Video Quality
Buffy The Vampire Slayer Season One was shot 4:3 for American Television. As a result the picture quality is not as high as one would expect and certainly not on a par with the latest Hollywood Blockbusters.

With a softer, muted picture Buffy doesn't really shine with detail. That said this is down to the original US source rather than the encoding of the Discs themselves. The first two series were filmed on 16mm stock and as such more grain and smearing is visible than expected.</font>
I'd confused "4:3 for TV" with being video. Funny though because playing it on WinDVD I could swear I was looking at video weave artifacts. ??

Quote:
<font face="Verdana, Arial" size="2">So you had the best luck with P-DVD 3.0? What refresh rate was your video card set to? Theoretically shouldn't 50 be ideal? Or 75 (25 X 3)?</font>
At 60 Hz. I use an Toshiba TN55x81 RPTV so I don't really have a choice.

- Tom




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(This sentience has tree errors.)
post #6 of 6
On this sort of material (24fps original/3:2 pulldown to 60Hz/video transfer to 50Hz) I have seen dTV's greedy deinterlace method work wonders. You can't get rid of motion artifacts but most of the weaving goes and a lot of detail is recovered.

Aside: when I started work on dTV most US shows shown in the UK appeared to transfered in this way, when I came back from my trip they seemed to have switched equipment and are now doing the "right" thing and speeding the programs up, this means even more space for ads though http://www.avsforum.com/ubb/frown.gif

John
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