A Post of No Redeeming Value: Aspect Ratio

[sisabet]

First things first: I am not computer savvy. I am not even all that program savvy when we talk about programs and such that I have used for years. Trust me - if there is a button to handle a task, I know the 12 step work-around and am totally ignorant of the fact that the button even exists.

Hence, Disclaimer: Any technical terms I get correct is due to luck. Any technical terms that I get incorrect... well do me a favor - assume *everything* is incorrect until proven true.


So, if you are like me you have a certain fondness for a little hobby I call, "Watchin' Stuff." If you are like me, you also give little thought to whether or not there are black bars on top of and below the stuff you watch. You might notice it more when you watch a movie or when you are at a party and want to appear all snooty and smart about movies (filmedjucated, if you will) and say things like it is a travesty to watch "Die Hard" in anything but the widescreen version as the creator intended. Then you flick your nose in the air and brush off some imaginary dust from your smoking jacket and a woman in a severe black bob and bright red lipstick hands you a martini and everyone laughs and it sounds like glass breaking. Outside of this occurrance, the subject probably isn't coming up all that much.

Unless you decide to vid. If you decide to vid then someone at some point will say two words to you and those words should strike fear and dispair into your heart. Those words should chill you to the bone and cause a strong woman to weep. Those words will keep you up at night and they will break you.

The words that I write of here, my friends, those words are Aspect Ratio.

Webster's defines aspect ratio as the specific point of any frame image where a vidder will, happily and with a song in her heart, rather fall upon a sword (and failing that, the sharp edge of a copier will do nicely) than fool with this fucking thing one second longer.

While I tend to agree with this definition, I think Webster's is being overly dramatic (as is his wont). Aspect Ratio is the word we use to describe what is going on here:

note: for dramatic purposes, please pretend the role of Vidder A and Vidder B are being played by puppets

Vidder A: Hey Vidder B, what's up.

Vidder B: Oh, not much vidder A. I'm working on my vid and it just looks funky.

Vidder A: How so B?

Vidder B: Well A, I am glad you asked. See that dude right there?

[Vidder B dramatically points to character in vid, wire controlling Vidder B's arm snaps and the studio audience ignores as they understand intent and all. Wow. I really love this studio audience. You guys are great]

Vidder A: The tall skinny fella?

Vidder B: Yeah.

Vidder A: He's kinda hairy but I don't see the problem.

Vidder B: Well, see that tall skinny fella is Gimli.*

AND SCENE!



*See, he is a DWARF!!! But he looks tall and skinny cause the aspect ratio is off! Geddit? See? No? Do not make me bring out more puppets.



Let us discuss for a moment. Once upon a time, there were movies and there was television. At the movie theater, the rectangle that made up the screen was much longer than it was tall.

The rectangle that made up your television set was not nearly shaped like a movie screen. Way back then, televisions all came in different sizes, but one thing was always consistant and that was the ratio of the height versus the width of the screen on all sets was the same (ratio of course is from the Latin word rat which means "small vermin who will fuck up your pre-algebra grade point average because you will never ever never understand probability, you brain damaged git").

Every show that you watched on your television filled the entire screen (remember this - "filled the entire screen" as it will figure in very prominently when we explain what full screen means). The reason, of course, is because it was against the law to not fill an entire screen of television under the Conservation and Regulation of Broadcast Signal Screen Space Act of 1952.

This was mainly because at that time, unfilled areas on a television screen would emit invisible spectrum light waves that were widely believed to cause people to become Communists. However, in 1971 a young scientist named Emmet Brown was successful in creating the first safely letterboxed image.

What did this technology do? Well - it enabled a television screen to have a black bar put across the very top and across the very bottom. This caused the viewable area of the television to actually shrink - but only if you were thinking in, you know, real numbers. If you abandoned the shackles of reality, you would realize that these bars actually increased the viewable area as now the rectangle that made up the screen was much wider than it was taller. Like a MOVIE THEATER only teeeny tiny.


Now as you all know, Congress in 1989, in a misguided attempt at deregulating the industry passed the Letterbox Act of 1992 which required all genre television shows to be broadcast for at least one season in full screen resolution and then to make a switch to this new widescreen technology after one season thru the series run because that just makes tons of sense.

What does this mean to you - a vidder? Well it means that if you are vidding Farscape then you have season one thru season 3 in full screen resolution. Full screen means that the show fills the screen. Now, just to make this complicated, I only mean that full screen fills the screen if you have a tradional size television.

If you have one of those fancy schmancy new fangled television with the wiiiide sides and the high def and the "oh look at me! I have a great television set and poor Liz is adjusting the brightness on her sanyo on a daily basis! MUAHAHAHAHA!!!" well you are just a Bastard Person!

Cause see there are now 2 different ratios televisions and television shows can come in (and again width v height) 4:3 (traditional TV, full screen) and 16:9 (widescreen).

If you are watching Season 4 of Farscape, you will note that unlike season 1-3, season 4 is widescreen. The black bars on your television is the letterboxing. This means that the television that you have is really a 4:3 screen ratio but the show you are watching is a show made at 16:9 and the bars are compensating for that fact.

If you have a 16:9 television and are watching Farscape Season one, then the black bars along the sides of the screen are called You Need to Shut Up About Your Fancy-Ass TV. Seriously. I am not kidding.

When you vid 16:9 source in a 4:3 frame, what happens is that the image is stretched and suddenly Fred goes from being tall and slender to completely disappearing. It is scary. Also - kind of like forshadowing for Angel Season 5. No? Just me? Fine. The big deal about Aspect Ratio is that all of these TV actress's are skinny enough. If you stretch them out anymore then terrible horrible things could happen to them. Just don't.

Conversely, if you accidentally squeeze fullscreen 4:3 footage into a 16:9 letterboxing, you have finally made the Olsen Twins look healthy. Congratulations.

Comments

[tzikeh.livejournal.com]

But what about anamorphic!?

*runs away*

[sisabet.livejournal.com]

You mean like Power Rangers?

[quinn222.livejournal.com]

Don't forget the dreaded pan and scan, which, thank God has been abandoned. It makes me insane when people complain about widescreen 'because they aren't seeing the whole movie.' Some of them believe me when I tell then if they get a film in full screen they are losing 1/3 of the film. Others don't. I figure they deserve to live life seeing 2/3rds of their films.

[sisabet.livejournal.com]

Oh no - you can totally get full screen movies. I constantly recieve them as gifts.

[quinn222.livejournal.com]

I know you can get them but my store (thank God) doesn't carry them. Several times a day I have to explain the difference to people who would rather have VHS because then they can see the whole fim. *sigh*

[debchan.livejournal.com]

Source clips with different aspect ratios are either A) why God invented Virtual Dub or B) because God hates me. Possibly both.

[sisabet.livejournal.com]

My VDub has a difficult time accepting that there are different aspect ratios. It wants to believe everything is 720x480 all the time regardless of what it sees. My VDub has a lot in common with my uncle the Fundamentalist Preacher.

[killabeez.livejournal.com]

Let's not talk about the Star Trek movie DVDs -- all of which are encoded at different aspect ratios.

All of them.

[sisabet.livejournal.com]

Ain't life fun?

[absolutedestiny.livejournal.com]

Aspect Ratios are like the universe... every time you try to explain, it just gets more and more complicated.

Once upon a time I thought that it was all simple enough. There was full screen and there was widescreen and the widescreen had the black bars and this was good because it mean't that I could see both sides of the chasm luke and leia have to swing across at the same time.

Then DVDs came out and with them came anamorphic images to maximise the bits. So, I had to learn that there were 4:3 images and there were 16:9 images with black bars filling the frame AND that there were 16:9 images streched up to 4:3 images....

but wait... some of the stretchy 16:9 images still have black bars... OH because movies are sometimes 2.35:1 so they need black bars to fit them into 16:9 space and THEN they are squshed to fit them into 4:3 space.. ok ok I'm getting this....

...then I discovered that TV "pixels" and PC pixels are not the same shape! That 720x480 is 4:3 on a TV but not on a PC! Then what happens to the stretchy 16:9 images?! OKOK 720x480 becomes 640x480 and 720x80 stretchy widescreen becomes 360x480. I think I'm getting all this...

But no! I was wrong! In fact 720x480 images are 704x480 images with bars on the sides to make them 720x480 so you've got to crop first and THEN make the 704x480 image to be 640x480. And then the 16:9 stuff gets more complicated again! and you have not only top and bottom bars to deal with but side ones too!

AND THEN some dvds come out with BIG bars on ALL sides because TV actually crop off some of the image and this is called overscan and that some dvds pad the image so that less real image is cut and now OMG the numbers just dont make any sense anymore!!!

and EVEN AT THIS POINT where you think your brain has well and truly melted you realise that melted does not mean vapourised and there is more to go... such as the fact that it's actually an active image of 710.85 x 486 with a pixel aspect ratio of 4320/4739 and then ::vapourise::

The really funny thing is that other than the big stuff like whether an image is squished or not is one thing, but you then have the harsh truth that the people making these DVDs don't really know the truth about aspect ratios either and will run in fear if you mention something like ITU-R BT.601.

I'm telling you, technological knowhow is some hideous cruel black hole that swallows you up but you never reach the centre as things get infinitely worse. People are better off not knowing. Ignorance is bliss. People with knowledge are just spoiling things for the rest of us.

[sisabet.livejournal.com]

People with knowledge are just spoiling things for the rest of us.

This is my new motto. I spent all weekend with Kill Bill and its amazing black bars of DOOM. Cause seriously - even at the correct aspect ratio, Uma Thurman looks incorrect.

:hed asplode:

[absolutedestiny.livejournal.com]

There is one good trick to know. When it comes to DVDs, the whole frame is only EVER one of two aspect ratios. When I say whole frame I mean all the pixels whether they have black bars or not.

Either the whole frame is 4:3 which means it mostly-looks-right when shown on a PC monitor pixel for pixel. This is when 720x480 (tv scale) can be resized to 640x480 (square pixels, PC scale) to look really right.

OR the image is 16:9 stretched into a 4:3 frame which means that it needs to be shrunk down to look right. 720x360 then adding black bars to make it 720x480 will make it the same aspect ratio as 4:3 dvds, and similarly 640x360 will make it look right on a PC monitor.

Any bars on the DVD you can ignore. Deal with the *whole frame* first. It's the whole frame that is either 4:3 or 16:9-stretched-out-into-4:3. There are only these two modes on dvds. Just make the frame not-stretched and then deal with any bars (adding or subtracting to make the frame the full thing) later and it should all work out.

Not the soundest, easiest or most logical advice in the world but knowing there are only two states can make thinking about it easier sometimes.

[sisabet.livejournal.com]

And it was! It was 16:9 but stretched into 4:3 *but* with the added black bars of doom to give the mistaken impression that some kind of attempt to get it to widescreen had occurred amongst the editing software. And yes - I wasn't sure if my software had attempted to letterbox without me. My computer tends to do its own thing regardless of my feelings. But then I did realize that the black bars were actually there from the source because the source is not 16:9 and lo and the heavens opened up and Bill was killed and we all lived to vid another day.

[absolutedestiny.livejournal.com]

Yeah I can get that, I know that editing programs like to interpret things and resize them to fit your project settings.

Try to remember that DVDs are always 720x480 pixels. If the file in your footage bin is 720x480 and it has black bars then you can be pretty sure that your editing program did not add them for you.

[kimera.livejournal.com]

Now I'm having flashbacks to the wonderful lecture we had in Film & Video production about rectangular and square pixels. I never knew it was possible to talk about pixels for three hours.

[sisabet.livejournal.com]

PLEASE TELL ME!!! What are Square Pixels (besides a delightful coming of age series starring an adorably dorky Sarah Jessica Parker)?

[absolutedestiny.livejournal.com]

You don't *really* want to know. It will only make the brain more hurty.

[sisabet.livejournal.com]

You sure? If I am exporting to make something into a DVD (eventually) I should avoid the square pixels? Cause Premiere seems to think so. Everytime I tried to get it to export in square pixels this weekend it would just shut down about halfway through the file. I assume this means Premiere is either a bitch or warning me to stay away. Possibly both.

[absolutedestiny.livejournal.com]

Can. Worms.
Ok here goes.

1) Not-sqaure pixels wtf?

On a dvd, there is an image which is 720x480. This is true of every NTSC dvd you will ever buy. 720x480 is not actually 4:3 in ratio. If you do the math, you find out that it's off. 640x480 is 4:3 720x480 is not.

However, TVs are 4:3 and they display dvds just fine. That's because they have not-square pixels. TV "pixels" are actually taller than they are wide. and so rectangular not square. This means that when 720x480 is shown on a TV it becomes 4:3.

2) OK so what does this mean when editing the stuff?

Editing programs tend to presume that you want the stuff you are editing to look 4:3 when you are editing it. So usually any 720x480 footage is interpreted as not-square pixels, sometimes known as 0.9 PAR (pixel aspect ratio). DV, for example, is always interpreted like this in most editing programs. This means that rather than showing the video as 720x480 it will be resized on your monitor to be 640x480 so that it looks 4:3 to you when you edit.

Graphics and other image you might create on a PC, however, will be square pixels because computer monitors have totally square pixels. In order for a square pixel image to have the same 'rationess' and look the same as a 0.9 ratio image, the image needs to be resized or cropped or whatever. Your editing program may or may not do this, it depends on whether you tell it to interpret the still as square pixels or as 0.9. As I said, many editing programs interpret all 720x480 source as being 0.9 PAR.

3) and what about exporting?

Well, honestly it generally doesnt matter. See, the pixel aspect ratio is about how something is interpreted. If you have a 720x480 source video and you export it 720x480 it's still going to have the same amount of pixels no matter what. When your editing program "resizes" your dvd footage to 0.9 PAR all it only does that on the preview monitor, the pixels are still the same.

The only way I could imagine this ever being an issue is if you have some footage which is being interpreted as square and some other footage which is being interpreted as not. If all your source footage is 720x480, though, it's likely to be interpreted universally the same. So, if everything you edit is in DV then you do not need to worry about pixel aspect ratios as by default everything will be set up correctly.

As I do not edit in DV (I edit in a virual, lossless mode) I tend to tell my editing software (Premiere) that everything is square pixels so that I can predict what is going on. 720x480 looks like 720x480 and exports as 720x480 looking the same as it did. That is fine for me and the way I like to do things but the end result is no different.

So now you know (sorta - I know its a bit mysterious in practice). Square pixels and not-square pixels are almost always about whether something is displayed unchanged or compensated so that the aspect ratio looks correct on a monitor. If you have a sources that are being interpreted differently by your editing software then it is possible that one will be resized to be the other but that really does depend on your program.

In short - keep them all the same, source settings, export settings, everything and you should be fine.

[sisabet.livejournal.com]

I kinda understood that.

::is afraid::

And you use avisynth - right? You pull right from the vob file - right.

[absolutedestiny.livejournal.com]

Yeah I pull right from the vob but by the time avisynth has processed it Premiere sees it as being Uncompressed RGB.

[sisabet.livejournal.com]

Yeah because you have to Cyrano De Bergerac the vob file right? Or Premiere will freak out and be all "I don't like vob files!" and cry and stuff even though it only *thinks* it doesn't like vob files and actually should stop being so damned close minded.

[rydra_wong]

This is true of every NTSC dvd you will ever buy.

But not the PAL ones, right?

*weeps Euro tears in the background*

[sdwolfpup.livejournal.com]

*raises hand* I want to know. I keep clicking and unclicking the 'square pixels' option with indecision.

[absolutedestiny.livejournal.com]

oh alright - see reply above :)

[lierdumoa.livejournal.com]

I had this problem! Source was 640x480 and I changed it to 720x480 cause it was still close enough that the aspect ratio change wasn't actually distracting. We, it was to me, but I don't count, I figure. And figured I'd keep the 640x480 for online distribution, but just stretch it for the m2v con submission version because I really didn't want to stick black bars into the con version or chop off the top and bottom to keep the aspect ratio. Or would it actually end up fullscreen since my m2v was not set to 4:3 display in TMPGenc? I think?

Hmmm.

[absolutedestiny.livejournal.com]

You were mostly correct in resizing up to 720x480 for encoding your m2v. Technically you are supposed to resize to 704x480 and add 8 pixels of black to the left and right but that's provided someone scaled it down correctly in the first place.

However setting 1:1 aspect ratio in TMPG was a bad idea because it wont work on dvd players which only recognise the 4:3 or 16:9 flags. 720x480@4:3 is the correct way to do it for making m2vs.

[lierdumoa.livejournal.com]

4:3 I think was the default? I left it at that.

[lierdumoa.livejournal.com]

Ah. Okay, the 8 pixels. Both my Gia DVD and my Gattaca DVD have this. It still confuses me a little with my OC DVD's because they had no 8 pixels of black on the sides and played fullscreen on PowerDVD when I maximized them on my screen. I can't quite remember but I'm pretty sure they played at 720x480 in VirtualDub, again w/out the 8 pixel border. instead of reverting to the 4:3 aspect ratio like they did in PowerDVD. The only other TV show footage I've worked with from DVD is Firefly, and that was all widescreen anamorphic.

[absolutedestiny.livejournal.com]

I know... that's because... well, who knows if the people making the DVDs know what they are doing?

[valarltd.livejournal.com]

All I know is Aspect Ratios kick my ass.

And turn Luke Skywalker into an El Greco angel.
(not that this is bad thing, but Chewie looks like a pipecleaner)

[lierdumoa.livejournal.com]

::pictures Chewie::

::bursts into giggles::

[gwynnega]

::shudders at mention of aspect ratio::

::shudders to remember the already thin Christopher Eccleston stretched to inhumanly skinny proportions::

[dualbunny.livejournal.com]

suddenly Fred goes from being tall and slender to completely disappearing.

::giggles like mad::

[elistaire.livejournal.com]

*brain hurts*

[sdwolfpup.livejournal.com]

You are a mad, evil, puppet-wielding genius.

And I HATE aspect ratios. *kicks them*

[sisabet.livejournal.com]

Well if puppets can teach kids about the alphabet and Jesus then surely explaining aspect ratio will be a piece of cake!

[renenet.livejournal.com]

Do you remember The Letter People?

[xanphibian.livejournal.com]

*falls over giggling*

[morgandawn.livejournal.com]

I sometimes dream I am running, running down the beach, feet sinking deeply into the sand, yelling: "Assssspecttttt Raaaatiooooooo..." in slow motion.

I am certain it is right behind me but I dare not look.

[killabeez.livejournal.com]

*choke*

Heeeeee!

[kimera.livejournal.com]

I have had this dream, except that instead of Aspect Ratio chasing me it is Title Safe.

[laurashapiro.livejournal.com]

I could not love you more right now.

[heresluck]

Dude. I have missed you and your brain SO MUCH, London notwithstanding.

[renenet.livejournal.com]

Brave little teapot!!! So cute!

Also, I second that emotion about Liz and her brain. (Liz, you would have gotten a kick out of h.l and me swearing up and down to Ian that you and your brain come across the same in person as you do on your LJ.)

[sisabet.livejournal.com]

I even *look* like my LJ. It is eerie.

[joesther.livejournal.com]

OMG. You are a genius and hilarious and this is the best post I've read in a long time.

Can't. Stop. Laughing.

[littleheaven70.livejournal.com]

Ah, aspect ratios. I started vidding completely oblivious to the fact that half my source was 4:3 and the other was 16:9. For Buffy and Angel both change about halfway through.

My solution is to always vid in the smallest aspect ratio of the source available. So if there's both kinds, I use 4:3. Any 16:9 footage gets the sides trimmed off (I created a preset crop in my editing program), and then I move the frame around to make sure my subject matter is still visible. I've hardly ever run across a bit of source where I couldn't lose the edges without compromising the image.

[sweeney32.livejournal.com]

Ah, aspect ratio! My #1 pet topic! Thank you for this. I can't believe I didn't discover this discussion until now!

So far, all the DVDs I've used (save one) have either been 16:9 aspect ratio or 4:3. Sometimes (rarely) they were 2.35:1 with black bars filling out the rest of the frame, so it's 4:3 according to MPEG Streamclip (my encoder of choice). Sometimes it's 16:9 with black letterbox bars filling it out so MPEG Streamclip thinks it's 4:3. Sometimes it's 2.35:1 with bars filling it out so it's 16:9, or it's plain 16:9 with no letterbox bars (these two last are the most common these days). And sometimes it's just 4:3. But recently I had a DVD (a new DVD) which was 16:9, looked 16:9 on TV, but MPEG Streamclip opened it like it was 4:3, so everyone looked all skinny and squished.

Fortunately, I saw that it was squished and I just encoded it as 16:9 so all is well, but I can see that this would be confusing to others who can't immediately tell what is squished and what isn't. So, the moral of the story is—check the encoder settings, check what the DVD sleeve says is the aspect ratio, but also LOOK at your footage and discern what it is. Most of the time (almost all of the time) your encoding program will give you the right aspect ratio. But you also have to use your eyes and really LOOK. Compare the faces of the actors to other videos (which you know are set to the right aspect ratio) and make sure that they look the way they are supposed to look. As a human being, you should be able to recognize other human beings' faces and figure out whether if they've been distorted or not. Unless, of course, you've got that disorder where you can't recognize people's features very well—but I doubt most vidders suffer from that affliction.

I've always had an eye for aspect ratio (to the point where it's like fingers down a blackboard to see a video that's any more than a little bit off-kilter), but I understand that not everyone sees it quite so keenly. But I refuse to believe that most people can't see when a video with their favorite actors is all skinny and elongated, or all fattened and stretched out sideways. They've just got to LOOK. But so many of them won't, I guess, which explains so much aspect ratio abuse on YouTube and elsewhere. It makes me want to cry (and then it makes me get very vocal and obnoxious about aspect ratio! ;-) ).