Comments on: tl;dr

tl;dr

31d1 — Tue, 13 May 2008 20:01:15 -0800

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.

By: Nabubrush

Nabubrush — Tue, 13 May 2008 20:20:38 -0800

Isn't there a YouTube link you could have posted to explain this? (This is good.)

By: spiderskull

spiderskull — Tue, 13 May 2008 20:26:14 -0800

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.

By: Armitage Shanks

Armitage Shanks — Tue, 13 May 2008 20:36:52 -0800

Great post, thanks! Ha, I love incredibly arcane bits of information. You might also like the 25-year-old BSD bug.

By: bigskyguy

bigskyguy — Tue, 13 May 2008 21:12:09 -0800

The former.

By: turgid dahlia

turgid dahlia — Tue, 13 May 2008 21:15:38 -0800

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.

By: Mapes

Mapes — Tue, 13 May 2008 21:16:50 -0800

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.

By: dammitjim

dammitjim — Tue, 13 May 2008 21:19:55 -0800

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?

By: turgid dahlia

turgid dahlia — Tue, 13 May 2008 21:20:00 -0800

Oh, upsampled, whatever!

By: 31d1

31d1 — Tue, 13 May 2008 21:23:12 -0800

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?

By: turgid dahlia

turgid dahlia — Tue, 13 May 2008 21:28:28 -0800

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 ;-))

By: 5MeoCMP

5MeoCMP — Tue, 13 May 2008 21:29:33 -0800

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 :)

By: GuyZero

GuyZero — Tue, 13 May 2008 21:30:17 -0800

AWESOME. Why has IEEE Spectrum not covered this? Catch up, Spectrum!

By: ZakDaddy

ZakDaddy — Tue, 13 May 2008 21:42:22 -0800

Wife: Bored to tears. Me: Riveted.

By: melissa may

melissa may — Tue, 13 May 2008 21:44:26 -0800

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.

By: jaimev

jaimev — Tue, 13 May 2008 21:54:08 -0800

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?

By: mrballistic

mrballistic — Tue, 13 May 2008 21:58:05 -0800

melissa - at the bottom of the article they link to a page that has a list of model numbers.

By: melissa may

melissa may — Tue, 13 May 2008 22:06:43 -0800

Gah, I didn't notice. Thanks, mrballistic!

By: caddis

caddis — Tue, 13 May 2008 22:42:38 -0800

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.

By: chudmonkey

chudmonkey — Tue, 13 May 2008 22:54:17 -0800

Thanks for this! I learned a lot, and I'm glad I did. Best of the web, indeed.

By: infinitewindow

infinitewindow — Tue, 13 May 2008 23:06:20 -0800

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).

By: billder

billder — Tue, 13 May 2008 23:09:50 -0800

mrballistic, I would find you here. My favorite line so far: "We'll go into more detail later,"

By: neetij

neetij — Tue, 13 May 2008 23:16:10 -0800

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?

By: caddis

caddis — Tue, 13 May 2008 23:36:29 -0800

Is the problem still around in DVD players that were made after 2003? yes What about Blu Ray players? no

By: JakeEXTREME

JakeEXTREME — Tue, 13 May 2008 23:37:46 -0800

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.

By: davejay

davejay — Tue, 13 May 2008 23:56:42 -0800

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.

By: JakeEXTREME

JakeEXTREME — Wed, 14 May 2008 00:01:12 -0800

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.

By: aubilenon

aubilenon — Wed, 14 May 2008 01:08:18 -0800

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.

By: sycophant

sycophant — Wed, 14 May 2008 01:47:56 -0800

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.

By: unSane

unSane — Wed, 14 May 2008 05:25:16 -0800

This is a really dumb bug, by the way. REALLY dumb.

By: unSane

unSane — Wed, 14 May 2008 05:26:28 -0800

Upsampling not upscaling.

By: Green With You

Green With You — Wed, 14 May 2008 06:26:29 -0800

This reminds me of this FPP about the JPEG algorithm from several months back.

By: Skorgu

Skorgu — Wed, 14 May 2008 07:48:20 -0800

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.

By: tadellin

tadellin — Wed, 14 May 2008 08:17:51 -0800

Bored to tears.

By: bz

bz — Wed, 14 May 2008 09:32:55 -0800

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.

By: schoolgirl report

schoolgirl report — Wed, 14 May 2008 09:44:42 -0800

Plate of Beans, the Criterion Edition.

By: LordSludge

LordSludge — Wed, 14 May 2008 10:19:13 -0800

So this explains why every movie for the past 15 years has SUCKED.

By: revmitcz

revmitcz — Wed, 14 May 2008 11:28:46 -0800

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!

By: LordSludge

LordSludge — Wed, 14 May 2008 12:19:50 -0800

Except for Fight Club. Fight Club was good.

By: GuyZero

GuyZero — Wed, 14 May 2008 12:54:15 -0800

I am Jack's Chroma Upsampling Error.

By: davros42

davros42 — Wed, 14 May 2008 16:35:32 -0800

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.

By: markr

markr — Wed, 14 May 2008 18:57:23 -0800

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.

By: oxford blue

oxford blue — Wed, 14 May 2008 19:11:33 -0800

Since reading this I've changed; I know the truth now. So cold...

By: ryanrs

ryanrs — Thu, 15 May 2008 03:11:25 -0800

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.