tl;dr
May 13, 2008 8:01 PM Subscribe
The Chroma Upsampling Error. This incredibly detailed explanation of a common bug in DVD players will likely either bore you to tears or be gripping and utterly fascinating.
Ha, I love incredibly arcane bits of information. Stuff like this isn't even generally relevant enough to bring up in conversations; I can't imagine any of even my closest friends being remotely interested in this.
But for some reason it's fascinating.
posted by spiderskull at 8:26 PM on May 13, 2008
But for some reason it's fascinating.
posted by spiderskull at 8:26 PM on May 13, 2008
Great post, thanks!
Ha, I love incredibly arcane bits of information.
You might also like the 25-year-old BSD bug.
posted by Armitage Shanks at 8:36 PM on May 13, 2008
Ha, I love incredibly arcane bits of information.
You might also like the 25-year-old BSD bug.
posted by Armitage Shanks at 8:36 PM on May 13, 2008
I think that people who are peering at the Toy Story DVD menu and looking for errors in the upscaled chroma are missing the point entirely.
posted by turgid dahlia at 9:15 PM on May 13, 2008
posted by turgid dahlia at 9:15 PM on May 13, 2008
One of my favorite things about humanity is that for essentially any issue, material, object, or behavior you can think of, someone has thought about it really deeply.
posted by Mapes at 9:16 PM on May 13, 2008 [6 favorites]
posted by Mapes at 9:16 PM on May 13, 2008 [6 favorites]
So wait, this article was published in 2001. Is this bug fixed by now? Do I have to get all close to my TV to see if I have this problem? Or is this just an example of how math and color theory can combine to create nerdly discourse?
posted by dammitjim at 9:19 PM on May 13, 2008
posted by dammitjim at 9:19 PM on May 13, 2008
Oh, upsampled, whatever!
posted by turgid dahlia at 9:20 PM on May 13, 2008
posted by turgid dahlia at 9:20 PM on May 13, 2008
turgid dahlia: "I think that people who are peering at the Toy Story DVD menu and looking for errors in the upscaled chroma are missing the point entirely."
Which is?
posted by 31d1 at 9:23 PM on May 13, 2008
Which is?
posted by 31d1 at 9:23 PM on May 13, 2008
It's for navigating to the hilarious bloopers!
(And I'm not having a go - the post was actually quite interesting in an "I've just forgotten how to drive" sort of way, chillax ;-))
posted by turgid dahlia at 9:28 PM on May 13, 2008
(And I'm not having a go - the post was actually quite interesting in an "I've just forgotten how to drive" sort of way, chillax ;-))
posted by turgid dahlia at 9:28 PM on May 13, 2008
Thanks for this post! I now understand the difference between 4:2:0 and 4:2:2 -- which, given that I've been doing a fair few videotape rips of old family content, has been one of those niggling "I should know more about this" feelings.
Pure geekery, for its own sake. Love it :)
posted by 5MeoCMP at 9:29 PM on May 13, 2008
Pure geekery, for its own sake. Love it :)
posted by 5MeoCMP at 9:29 PM on May 13, 2008
AWESOME. Why has IEEE Spectrum not covered this? Catch up, Spectrum!
posted by GuyZero at 9:30 PM on May 13, 2008
posted by GuyZero at 9:30 PM on May 13, 2008
This is truly fascinating, in no small part because I've been projecting a lot of movies lately at home, have noticed this, and had no idea what the hell is going on. Are there any DVD players on the market without this flaw? I didn't see mention of that in the article.
posted by melissa may at 9:44 PM on May 13, 2008
posted by melissa may at 9:44 PM on May 13, 2008
Fascinating...but the article was last updated over 5 years ago. What's happened since then? Have manufacturers been hit with the clue stick hard enough to make this problem disappear completely?
posted by jaimev at 9:54 PM on May 13, 2008
posted by jaimev at 9:54 PM on May 13, 2008
melissa - at the bottom of the article they link to a page that has a list of model numbers.
posted by mrballistic at 9:58 PM on May 13, 2008
posted by mrballistic at 9:58 PM on May 13, 2008
Gah, I didn't notice. Thanks, mrballistic!
posted by melissa may at 10:06 PM on May 13, 2008
posted by melissa may at 10:06 PM on May 13, 2008
This is why you need Blue Ray, but then if it were me, perhaps I would first need a better tv than my late 80's 19" color tv through which to play my shiny discs.
posted by caddis at 10:42 PM on May 13, 2008
posted by caddis at 10:42 PM on May 13, 2008
Thanks for this! I learned a lot, and I'm glad I did. Best of the web, indeed.
posted by chudmonkey at 10:54 PM on May 13, 2008
posted by chudmonkey at 10:54 PM on May 13, 2008
Fascinating. Insider DVD geekery follows.
This explains so much... why serious authoring firms use Panasonic emulators for critical viewing (Matsushita, Panasonic's parent, avoided this bug in their hardware), and why the menus from that one dude always look bad (he gets his frame grabs from a software decoder that includes this bug).
posted by infinitewindow at 11:06 PM on May 13, 2008
This explains so much... why serious authoring firms use Panasonic emulators for critical viewing (Matsushita, Panasonic's parent, avoided this bug in their hardware), and why the menus from that one dude always look bad (he gets his frame grabs from a software decoder that includes this bug).
posted by infinitewindow at 11:06 PM on May 13, 2008
mrballistic, I would find you here.
My favorite line so far: "We'll go into more detail later,"
posted by billder at 11:09 PM on May 13, 2008
My favorite line so far: "We'll go into more detail later,"
posted by billder at 11:09 PM on May 13, 2008
tl;dr;dc (too long; _did_ read; don't care). It was interesting for a little while, then I realised I don't (want to) care about this stuff.
The article is dated to 2003. Is the problem still around in DVD players that were made after 2003? What about Blu Ray players?
posted by neetij at 11:16 PM on May 13, 2008
The article is dated to 2003. Is the problem still around in DVD players that were made after 2003? What about Blu Ray players?
posted by neetij at 11:16 PM on May 13, 2008
Is the problem still around in DVD players that were made after 2003?
yes
What about Blu Ray players?
no
posted by caddis at 11:36 PM on May 13, 2008
yes
What about Blu Ray players?
no
posted by caddis at 11:36 PM on May 13, 2008
What about Blu Ray players?
As Blu-ray uses both MPEG-2 or MPEG-4 then it certainly can be a problem. That is, if it hasn't been addressed since 2003 when this article was last edited.
posted by JakeEXTREME at 11:37 PM on May 13, 2008
As Blu-ray uses both MPEG-2 or MPEG-4 then it certainly can be a problem. That is, if it hasn't been addressed since 2003 when this article was last edited.
posted by JakeEXTREME at 11:37 PM on May 13, 2008
I expected to be riveted. Instead, surprisingly, I was bored to tears. But I take this as a personal failing rather than a fault with the FPP.
posted by davejay at 11:56 PM on May 13, 2008
posted by davejay at 11:56 PM on May 13, 2008
Ok, kick me in the head because for some reason I completely missed out on the word upscaling. Blu-ray movies are 1080p so there is no upscaling required. I don't think it would affect downscaling to 720p/768p, so I stand corrected.
Now it might have an effect on DVDs that you play on the Blu-ray players since they upscale DVDs. Again, that is if the problem hasn't been addressed.
posted by JakeEXTREME at 12:01 AM on May 14, 2008
Now it might have an effect on DVDs that you play on the Blu-ray players since they upscale DVDs. Again, that is if the problem hasn't been addressed.
posted by JakeEXTREME at 12:01 AM on May 14, 2008
JakeEXTREME: The upscaling here is not in the sense of going from 480p to 720p or whatever, but in the sense of upscaling the compressed lower-resolution chroma to the full picture resolution. So, as they explain, on a 480p image at 4:2:0, you have 240 scanlines of color information, which you have to upscale to 480 lines in order to display your 480 lines of luma information.
posted by aubilenon at 1:08 AM on May 14, 2008
posted by aubilenon at 1:08 AM on May 14, 2008
It's quite amazing how much you can downscale chroma resolution before it really affects the overall look of the image.
In this case it is a combination of two factors, an inherent design limitation in 4:2:0 colour sampling (it's not especially well suited to interlaced footage) and a poor implementation of that system (in handling all frames as if they were progressive).
It's pretty weird when you realise how shit video really is, generally. The MPEG-compressed TV many of us watch all the time runs at incredibly low bitrates. Many TVs offer woefully inadequate pixel resolution.
posted by sycophant at 1:47 AM on May 14, 2008
In this case it is a combination of two factors, an inherent design limitation in 4:2:0 colour sampling (it's not especially well suited to interlaced footage) and a poor implementation of that system (in handling all frames as if they were progressive).
It's pretty weird when you realise how shit video really is, generally. The MPEG-compressed TV many of us watch all the time runs at incredibly low bitrates. Many TVs offer woefully inadequate pixel resolution.
posted by sycophant at 1:47 AM on May 14, 2008
This reminds me of this FPP about the JPEG algorithm from several months back.
posted by Green With You at 6:26 AM on May 14, 2008
posted by Green With You at 6:26 AM on May 14, 2008
I'm sad to say I found this just as riveting now as I did the first time I read it a year ago.
I'd really like them/someone to specifically address computer DVD drives and software decoders (VLC, mplayer, xine, etc). But then, as demonstrated, I'm a huge geek.
posted by Skorgu at 7:48 AM on May 14, 2008
I'd really like them/someone to specifically address computer DVD drives and software decoders (VLC, mplayer, xine, etc). But then, as demonstrated, I'm a huge geek.
posted by Skorgu at 7:48 AM on May 14, 2008
It is an upscaling issue in both X and Y dimensions. The chroma information is scaled 2X and the scaling looks [even more] bletcherous if the interpolation method is not matched and optimized for either field-based (interlaced) or full-frame based (progressive) material. Two different scaling algorithms and the ability to reliably identify field or frame sources and switch to the correct method are needed.
posted by bz at 9:32 AM on May 14, 2008
posted by bz at 9:32 AM on May 14, 2008
Plate of Beans, the Criterion Edition.
posted by schoolgirl report at 9:44 AM on May 14, 2008 [1 favorite]
posted by schoolgirl report at 9:44 AM on May 14, 2008 [1 favorite]
So this explains why every movie for the past 15 years has SUCKED.
posted by LordSludge at 10:19 AM on May 14, 2008 [2 favorites]
posted by LordSludge at 10:19 AM on May 14, 2008 [2 favorites]
And here I was wondering for the past year and a half why I kept getting pixelated edges on deep reds in DVDs I was authoring. OS X's own DVD Player app (and DVD Studio Pro) both suffer this issue, but I had not the tech know-how to figure out what to google for in fixing it. Also, that it happened to every DVD I own (not just ones I produced) made me feel like it was a non-issue.
And to think my friends thought I was crazy when I pointed it out and they couldn't see it. I'll show them! Oh yes, I will!
posted by revmitcz at 11:28 AM on May 14, 2008
And to think my friends thought I was crazy when I pointed it out and they couldn't see it. I'll show them! Oh yes, I will!
posted by revmitcz at 11:28 AM on May 14, 2008
Except for Fight Club. Fight Club was good.
posted by LordSludge at 12:19 PM on May 14, 2008
posted by LordSludge at 12:19 PM on May 14, 2008
Since I get this error everyday working in Final Cut Pro, yes it definitely still is an issue... at least now I know what name of it is.
posted by davros42 at 4:35 PM on May 14, 2008
posted by davros42 at 4:35 PM on May 14, 2008
I've certainly heard of blu-ray (and HD-DVD) players having this problem when playing back DVDs. I'm assuming actual blu-ray disks have finally ditched interlacing though so hopefully it isn't a problem there. Now that interlacing is finally dying off it's time to work on killing overscan, it's not the 50s anymore people.
posted by markr at 6:57 PM on May 14, 2008
posted by markr at 6:57 PM on May 14, 2008
Since reading this I've changed; I know the truth now.
So cold...
posted by oxford blue at 7:11 PM on May 14, 2008
So cold...
posted by oxford blue at 7:11 PM on May 14, 2008
Wait until you hear about the OpenGL texture sampling / gamma 1.0 bug. Well, not a bug, more like laziness, or computational feasibility, or mildly defensible corner-cutting.
If you come across an OpenGL rendering that shows texture aliasing or moire patterns, try viewing the image on a display calibrated to gamma 1.0. The patterns will often disappear. It's not a very subtle effect. And it's not just OpenGL—most image resamplers are broken in this way.
Reason: linear interpolation only looks good on linear output devices.
Note: you don't need the OpenGL app, just its output. A screenshot is sufficient.
posted by ryanrs at 3:11 AM on May 15, 2008
If you come across an OpenGL rendering that shows texture aliasing or moire patterns, try viewing the image on a display calibrated to gamma 1.0. The patterns will often disappear. It's not a very subtle effect. And it's not just OpenGL—most image resamplers are broken in this way.
Reason: linear interpolation only looks good on linear output devices.
Note: you don't need the OpenGL app, just its output. A screenshot is sufficient.
posted by ryanrs at 3:11 AM on May 15, 2008
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(This is good.)
posted by Nabubrush at 8:20 PM on May 13, 2008