How To: Find your DVD's correct AR frame size.

[Bassphine]

This guide is to help convert DVD's back to their original aspect ratio for full resolution encoding.

For this guide I will be using 2.35:1 as the example aspect ratio. However there are over 30 other aspect ratios as well. Here I name a few of the most common ones used by the movie industry in DVD's that I have come across so far.

1.33:1 4:3 for standard television
1.77:1 16:9 for standard widescreen televisions
1.85:1 Very common
2.20:1 I have seen a few of these DVD's around
2.35:1 Very common

Information that I use to get the correct aspect ratio.

DAR - DVD's have 2 flags otherwise known as DAR's (Display Aspect Ratios). These are 1.33 for fullscreen [4:3] and 1.77 for widescreen [16:9], these flags tell a player how to correctly display the image on your screen.

AR - Movies are produced in many types of frame formats, otherwise known as AR's (Aspect Ratios)

DVD - They are created the way they are in order to maintain maximum compatabilty with existing 4:3 televisions, by squeezing the image and letterboxing it to 720x480 (720x756 for PAL) they are able to cator to existing users with older t.v.'s and new users buying newer widescreen t.v.'s as well.

Widescreen - True widescreen is 16:9 or 1.77 all the others are anamorphic widescreen.

Anamorphic Widescreens - These are movies squeezed horizontally to fit 720x480 (720x756 for PAL) in order to maintain compatabilty for both 4:3 and 16:9 screens.


Figuring out your movies true frame size.

To find the true frame size for a DVD video we have to use the DAR, and AR information known to us. If you don't know your movies AR then look it up on IMDB it's usually listed in the DVD info section. We also need to know the mpeg resolution, of course it helps that it never changes from 720x480 (720x756 for PAL) as it is the standard for DVD video.

O.k. now for the math, this is actually really easy.

Lets take an NTSC Widescreen DVD, with a 2.35:1 AR.

Multiply the height, by the DAR flag. This is widescreen, so we use 1.77 (16:9), instead of 1.33 (4:3)

480 x 1.77 = 848 (rounded to the nearest divisible 16)

This is our movies true frame width. Then divide this width by the movies AR of 2.35

848 / 2.35 = 368 (rounded to the nearest divisible 16)


So this movies actual frame size would be 848 x 368.


Heres a couple of tables to help you. Please remember that all numbers are rounded to the nearest number divisible by 16.

480 x 1.77 = 848 divided by

2.40 = 352
2.35 = 368
2.20 = 384
1.85 = 464
1.77 = 480

Now for those of you that use PAL

576 x 1.77 = 1024 divided by

2.40 = 432 (416 may work however 432 is the closest divisible 16 number)
2.35 = 432
2.20 = 464
1.85 = 560
1.77 = 576


Will be adding more information as needed.

edited on 12/20/05 to reflect new information regarding proper multiplyer ratio in relation to widescreen width. It seems DVD authoring companies use both 1.77:1 and 1.78:1 when they use their formula to produce anamorphic DVD's. When in doubt use both and check them to the original source to see which one displays more correctly. Though they should be virtually identical. Added PAL AR resolutions. Ditched the 'accidental' 4:3 flag for widescreen since it is supposedly very rare and I've never heard of it accept from a couple of people and they probably couldn't figure the formula to begin with. Edited and tidied up the explanations to be more user friendly.

[Episodio1]

"height 480 x 1.78 = 852
"852" is our movies true frame width."

I dont get it. You are expanding the frame of a 16:9-DVD, when you should squeeze it.

edited: maybe you should start from the dvd WIDTH and divide it. Instead of starting from the height and multiply it. ;)

[Bassphine]

A DVD is already squeezed, you need to unsqueez it.

The movie is captured into a widescreen format then squeezed on the horizontal to fit into a 4:3 AR area. If you squeeze a DVD back into a proper AR using vertical resizing you decrease the resolution cause you've just squeezed it a second time.

While it can be said that doing both a horizontal and vertical resize can produce a more compressable movie because it reduces the number of pixels in each frame it also produces detail and quality loss as well.

95% of the people do not understand the complete timeline for a DVD to be produced from film to DVD, and I'm not going to say that I do either. However I've watched some of the people that work at a DVD production studio here locally, and I've been privy to watch the process.

For the most part it is rather boring yet interesting indeed, the film transfer process is rather simplistic if not complicated. The reel is fed into a frame scanning machine and each frame is automaticly scanned advanced and scanned and so on. Each frame is captured in what was told to me as a very high resolution and uncompressed image, which can be reduced to fit what ever medium a studio wants.

I'm getting off track here, I loved that place, back to the subject at hand. When I was introduced to the people that take the by then already downsized video and transfer it to mpeg2 for DVD they had a project open. While I was looking at the project I witnessed them squeezing the image on the horizontal to fit the 4:3 AR, asking them about the process this is what they had to say.

The DVD format in it's entirety is a hack job to begin with, the standards were Ill thought out and not implemented very well when the format started. Well you could imagine my reaction to that, I was surprised, stunned even to hear that from the man that is responsible for creating DVD movies that you have probably watched.

It seems that not only do our good people here online improperly resize frames but the whole DVD standard does as well, infact it works because it does it wrong. Hows that for karma?

The only feature implemented properly is display on a widescreen t.v. where the DAR flag says 16:9 and the video is stretched horizonally as it should be to fit the screen. Everything else uses a second squeeze which reduces the overall resolution of your movie, including software based decoders. Although there are now supposedly some software decoders that stretch rather then squeeze the image, don't personally know of any though.

Anyways this is the method that he told me to return a DVD frame back to it's original AR. Since he's the guy doing the squeezing I'ma have to trust him on it since it is reproducible and predictable.

The only unpredictable part is adjusting the width to compensate for any loss of height when cropping out the black bars, all the while trying to stay in the mpeg4 standard of 16x16.

"height 480 x 1.78 = 852
"852" is our movies true frame width."

I dont get it. You are expanding the frame of a 16:9-DVD, when you should squeeze it.

edited: maybe you should start from the dvd WIDTH and divide it. Instead of starting from the height and multiply it.

The DVD itself is not 16:9 it is 4:3 by increasing the width on the horizontal you are then creating a 16:9 DVD, and as explained for a second time if you squeeze it on the vertical you decrease the resolution.

BTW by increasing it in this manner it is no longer NTSC compliant for television so if you plan on doing a DVD to DVD transfer then you are going to have to live with the reduced resolution.

Then again if you plan on putting it back to DVD later on down the road you could do the process in reverse and set the DAR flag to 16:9 in which case you sacrifice resolution again.

[Teegedeck]

This has been done before. Please see the guide by SeeMoreDigital:

http://seemoredigital.net/03_Video_Only_Info/What_is_an_anamorphic_encode.html

[Bassphine]

This has been done before. Please see the guide by SeeMoreDigital:

Not true, it looks like he covers the concept of stretching horizontally, however he uses the xvid stretching pixel method which is very buggy and is usually ignored entirely by decoders. Also I give a complete formula for finding the height and width of the original frame resolution size.

In order to keep my explanation as simple as possible I have only talked about PAR here. However, as with most things in life, there are other methods of changing the shape of the video images you will see on your PC or TV display screen.
One such method is by changing the DAR (Display Aspect Ratio). However, true DAR is a far more powerful tool than PAR and will be discussed later on another web page.

LOL looks like he is in agreement with me.
Like I have already admited though the resolution is not NTSC DVD compliant so if later on down the road you wanted to return the video to DVD you can just by doing all the steps in reverse.
Note you will not have downsampled the resolution using this method, so when squeezing back to 720x480 you will lose less quality then if say you were to downsample to 640x272 (2.35:1) or even 528x224, (2.35:1) both of which downsample resolution in favor of fewer pixels to encode, increasing overall compressability.

Bassphine

[Bassphine]

After rooting around some more, I came up with this table from SeeMoreDigitals site provided to me be Teegedeck

NTSC 16:9 TV/PC Monitors and 480 (i and p)
Frame Aspect Ratio = 1.77:1 = 'True 16:9 Frame'

Picture To Nearest To Nearest
AR 16th Pixel Full Pixel

1.77:1 848x480 853x480
1.85:1 848x464 853x462
2.35:1 848x368 853x363
2.40:1 848x352 853x356

He seems to use a 16:9 = 1.77:1 AR in his formula, The guy down at the DVD production company said they use 1.78:1 AR in their formula.

It's possible that different DVD masterers use slightly different formulas, so long as the output on screen after the DAR flags are used is correct it really doesnt matter if there is a slight variance because visually they will look the same to a user who is not counting the lines of reolution.

With my formula 2.35:1 is 852x360, his it is 848x368 both of which seem to work just fine.

I will ask about his 1.77:1 AR for correcting framesize down at the DVD company. If in fact it is right I will correct my original post and we will have a correct guide here.

Though now that I'm thinking about it he may be right because I had to correct my width to compensate for a few pixels of height loss when I cropped out the black bars my resulting res. was 848x360 it is entirely possible that I cropped out 8 pixels total from the height which would have made it 848x368.

Hmm now I am going to have to check this out ;-/ I hate being wrong. lol. In my own defense though I have been using my formula for awhile now and it has worked flawlessly in my favor.

Bassphine

[Bassphine]

O.k. after talking with my friend at the company this is what he explained to me.

1.77:1 is the correct AR that should be used in the formula when mastering DVD's, however this is not always the case. Some companys perfer to round to 1.78:1 AR because the results are the same and un-noticable.

This is why he explained to me to use 1.78:1 to stretch the frame back out to its normal size because this is the AR his company uses to master DVD's.

So to cap it off 1.77:1 is the correct AR to stretch with, however 1.78:1 is also used by some DVD masteres as well. The only way to really tell is to use both methods on a frame from your movie and compare them to an original frame captured from your movie while at full res. (maybe power dvd?)

I'm going to change my guide to reflect this new information.

Bassphine

[Backflip]

What are your numbers for PAL? Thanks :)

[Bassphine]

PAL would be;

576 multiplied by 1.77 = width, width divided by AR = height. (width x height)

or

576 x 1.77 = 1024, 1024 / 2.35:1 = 432 (1024 x 432)

I guess it's time I made a PAL table on my guide

Bassphine

[fight2win]

thanks bassphine for this useful post

[chilledoutuk]

I am not sure in the point of resizing to square pixel instead of using a container format that supports anamorphic video such as .mp4 and setting the same PAR as the source material.
Its so easy to just open the video in dgIndex crop it and then set the par in the encoder to that of the source and thus there is no resizing of the video which itself looses information.

In my opinion there are too ways to go about it:
1. Reduce the resolution for lower bitrate encodes
2. Encode the video without any resizing and set the par in the stream either in the
encoder or using mpeg4modifier then mux into a .mp4 container along with your main audio and any other tracks such as directors comentry.

by the way this topic discussed to death about neally 2 years ago.

[IvS]

chilledoutuk: this thread doesn't discuss the cons and pros of resizing video, it discusses methods to find DVDs' aspect ratios. This wasn't "discussed to death". Anyway, I don't see how you "lose" any detail if you round a video to square pixels while keeping full width and height. Plus when doing that, you can use a high quality resizer like lanczos4 and you don't have to let anything work unnecessarily to "fix" the aspect during decoding.

[Bassphine]

thanks bassphine for this useful post
Your welcome, I hope you find good use for it.

I am not sure in the point of resizing to square pixel instead of using a container format that supports anamorphic video such as .mp4 and setting the same PAR as the source material.
Its so easy to just open the video in dgIndex crop it and then set the par in the encoder to that of the source and thus there is no resizing of the video which itself looses information.

In my opinion there are too ways to go about it:
1. Reduce the resolution for lower bitrate encodes
2. Encode the video without any resizing and set the par in the stream either in the
encoder or using mpeg4modifier then mux into a .mp4 container along with your main audio and any other tracks such as directors comentry.

by the way this topic discussed to death about neally 2 years ago.
By setting the PAR instead of resizing back to the original size poses a very serious problem for people who do not have the correct decoders or even if the 'mp4 compliant' player they use doesn't support every feature of mp4, or any other problem that may arise for any other reason. Like I always say if you're going to do something right do it yourself, to depend on a container to decode and do the dirty work is well in my opinion as being lazy. No offence to you if it works for you then it works for you it's a personal decision, I for one have to be able to play back the disc on a number of computers in my house and work and occasionally abroad if I'm on business, I like to know that it's going to play everywhere I'm going to play it.

Resizing the video back to it's original size does not lose information at all, it merely stretches the video back to it's original size just as it would if you played it in a widescreen t.v.

As for reducing the resolution for low bitrate encodes, you could do that, but that is not what this guide was intended for. This guide is intended keep the original movie size for full frame resolution video encoding, hence the title of this guide.

As for being talked to death I wouldn't know, I've been mucking around in this for a little while now and learned about this technique awhile ago and it has worked great for me. I'm just giving back to the community in what little way I can, I'm not asking for praise, apprecitation or anything like that. Like all guides it's meant as a guide nothing more use it or pass it it's up to you.

Bassphine

[chilledoutuk]

@ IvS This thread is about resizing anamorphic video on the x axis so that it has square pixels do i need to explain the relevance of my post to you?

1. Resizing using lanzos uses considerable cpu time especially when upscalling

2. Unless you encode at quant 2 at a specified bitrate 720x576 anamorphic encodes will always look better than a 1024*576 encode.

3. 720*576 anamorphic encodes are more compatible with standalone players in my experiance than 1024*576 encodes.

4. codecs will take more time to encode as video at 1024*576 time that could be spent on more powerful RDO.

5.What makes you think that 1024*576 was the orginal resolution of 720x576 16:9 dvds just because thats what the square pixel resolution is when you keep the verticle resolution.
whats to say they didnt encode from a hdtv 16:9 source and resize to 720*576.

6. It is a simpler process to encode videos with a PAR and crop without having to worry about calculating the aspect ratio for square pixel output.

Anamorphic Widescreens - These are movies squeezed horizontally to fit 720x480 (720x756 for PAL) in order to maintain compatabilty for both 4:3 and 16:9 screens.
So are you saying that 4:3 widescreen letterboxed dvds are not compatible with 16:9 screens?

The fact is that the reason anamorphic widescreen dvds exist is that they wanted to utilise the full resolution available in the specified dvd frame resolution.
For people with 4:3 telivisions of regular size they would not notice the quality difference between 16:9 video in a letter boxed 4:3 frame or a anamorphic dvd (thats why they get away with releasing letterboxed 16:9).

The problem with this method is that when zoomed in on a large widscreen or high resolution telivsion the resolution is insuffcient and basically looks shit. this is why they created anamorphic 16:9 widescreen video dvd's.

One extra point even 4:3 dvds are anamorphic in fact they all are as:
4/3 =1.33:1
720/576=1.25:1


Oh by the way heres a proper guide i wrote about 2 years ago

http://www.aoul98.dsl.pipex.com/tutorials/aspectratio/aspect.htm

[Bassphine]

1. Resizing using lanzos uses considerable cpu time especially when upscalling

IMO not really, I haven't noticed any unusual cpu buildups as of yet.

2. Unless you encode at quant 2 at a specified bitrate 720x576 anamorphic encodes will always look better than a 1024*576 encode.

That's an objective comment as everyone has a different view on what they think is best.

3. 720*576 anamorphic encodes are more compatible with standalone players in my experiance than 1024*576 encodes.

I've already mentioned this at least 3 times now. Yes the full scale resolution is incompatible with all standalone non-computer powered displays. However the process can be reveresed later and put back to DVD for compatibility.

4. codecs will take more time to encode as video at 1024*576 time that could be spent on more powerful RDO.

It just takes more time overall to encode as far as I can tell. Personally speaking the quality is better much better then downsized video.

5.What makes you think that 1024*576 was the orginal resolution of 720x576 16:9 dvds just because thats what the square pixel resolution is when you keep the verticle resolution.
whats to say they didnt encode from a hdtv 16:9 source and resize to 720*576.

LOL if you have been following this entire thread you would know that I have been visiting and making friends at the local DVD mastering studio. Why would a DVD mastering studio use such a low resolution of an HDTV source for the final production DVD? Wait they can't because the HDTV source is created from the original film transfer that is used to also create the DVD source.

6. It is a simpler process to encode videos with a PAR and crop without having to worry about calculating the aspect ratio for square pixel output.
{QUOTE]
Anamorphic Widescreens - These are movies squeezed horizontally to fit 720x480 (720x756 for PAL) in order to maintain compatabilty for both 4:3 and 16:9 screens.[/QUOTE]

Again as mentioned before PAR is at this point and always will be IMO an unreliable method as the mp4 container is the only one I believe that can decode that information and that's assuming the decoder on someone elses end supports that function.

So are you saying that 4:3 widescreen letterboxed dvds are not compatible with 16:9 screens?

Read the above quote for previous answer and read it reaaallly slowly note the word in bold, what does it say?

The fact is that the reason anamorphic widescreen dvds exist is that they wanted to utilise the full resolution available in the specified dvd frame resolution.
For people with 4:3 telivisions of regular size they would not notice the quality difference between 16:9 video in a letter boxed 4:3 frame or a anamorphic dvd (thats why they get away with releasing letterboxed 16:9).

Of course they wouldn't notice too much of a difference, the dot matrix of a TV, pales in comparison to that of a PC monitor. For example when I used to transfer my media to DVD, the artifacting that appeared when watched on a PC monitor where virtually blended and looked quite normal when watched on a TV. Not sure if that's what you are talking about but it seemed relevent.

The problem with this method is that when zoomed in on a large widscreen or high resolution telivsion the resolution is insuffcient and basically looks shit. this is why they created anamorphic 16:9 widescreen video dvd's.

Um again this is subjective, but as an owner of a high quality DProjector of 102'' the resulting video file using my method in comparison of downsized video and PAR enabled video, is that Original AR frame size wins out. However this is my opinion only others may have other opinions, I at least seem to be respecting that.

One extra point even 4:3 dvds are anamorphic in fact they all are as:
4/3 =1.33:1
720/576=1.25:1

What? do you know what the 1.33:1 really represents? 4:3 is 4 units by 3 units expressed as 1.33:1, or for every 4 units wide it is 3 units high. This is not anamorphic as the image is never 'squeezed' out of shape to fit this standard image size of 4:3. The same for PAL as well except PAL is 5:4.
The aspect ratio of an image is its displayed width divided by its height (usually expressed as "x:y")
So the correct table should be

For NTSC
Digital Standard = 720x480
Actual Screen size = 700x525 (525 with only 480 visible, other lines are used for information. 700 is displayed as 720.)
AR = 1.33:1
AR Simple = 4:3

Digital Standard= 720x576
Actual Screen Size = 781x625 (625 with only 576 visible, other lines are used for information. 781 with overscan results in 720)
AR = 1.25:1
AR Simple = 5:4

Note that NTSC has a smaller width then the digital standard, when playing back content originally created for 4:3 broadcast the 4:3 image has spaces to the left and right. These spaces are either boxed or hard encoded from the original material. Players can sometimes scale this image to remove this effect causing the top and bottom to be clipped from view, the amount is so little as to be unnoticable.
Also note that the width is subjective to the height, depeding on the media involved it can go up and down and is automaticly scaled to fit the t.v. used. Here are some examples:

VHS/VHS-C
220 - 240 lines
BETA
250 lines
8mm
250 - 280 lines
SuperBETA
270 - 280 lines
Analog TV Broadcast
330 lines
Analog Cable TV
330 lines
Standard Digital Cable
330 - 500 lines (Depends on original source of the signal and compression used in downloading to the cable box)
S-VHS/S-VHSC
400 lines
DVD-R/-RW/+R/+RW
250 - 400+ lines (Depends on recording mode and compression used)
Laserdisc
400 - 425 lines
Hi8
380 - 440 lines
Digital 8
400 - 500 lines
miniDV
400 - 520 lines
microMV
500 lines
ED BETA
500 lines
Commercial DVD
Up to 540 lines

Oh by the way heres a proper guide i wrote about 2 years ago

http://www.aoul98.dsl.pipex.com/tut...atio/aspect.htm

Again this is yet another guide that uses PAR or downsizing the frame size to achieve similir results, how many times do I have to say that my method is for achieving the max original frame size? My method creates a universal playing file for PC's in any video format without sacrificing the horizontal resolution.

Bassphine

P.S. any more posts that involve subjective comparisons to PAR, downsizing etc. will be ignored by me. Unless a post has relevent information and or questions relating to the quide they will be ignored by me. Have a good day. :D

[chilledoutuk]

Bassphine for someone that types a lot you don’t SAY VERY MUCH!!!

Look mate you have mentioned dvd mastering studios or whatever but that means nothing to me after seeing some of the things these studios try to pass off as decently produced DVDs.

Everyone that knows anything about PAR and DAR knows that even 720x576 4:3 content is anamorphic. Maybe not by much but it still is slightly anamorphic and thus resized to maintain the original 4:3 aspect.

Last time i checked mate 720/480 does not equal 1.33:1 but 1.5:1 rather.

What i am saying is that the aspect ratio of a 720x480 square pixel is much wider than 1.33:1 and thus either DAR or PAR is used to resize the video to the correct aspect.

What? do you know what the 1.33:1 really represents? 4:3 is 4 units by 3 units expressed as 1.33:1, or for every 4 units wide it is 3 units high. This is not anamorphic as the image is never 'squeezed' out of shape to fit this standard image size of 4:3. The same for PAL as well except PAL is 5:4.

WHAT!!! [edited by Teegedeck]

Could you please explain this to the XVID devs without getting [edited by Teegedeck] flamed to the moon and back as according to them it’s very much needed to resize 4:3 pal and NTSC content.

Have you actually looked at the guide I wrote 2 years ago it does exactly what your guide does and more. In short I mention that if you want square pixel but don’t want to reduce the resolution that it is an option to keep the vertical resolution as is and only stretch the picture horizontally.

Ok you have a projector what’s the resolution of that if its 1024 that explains why 1024 encodes seem better. Perhaps if you got a decent scalar for your projector you would not need to encode to 1024.

by the way my opinion must be correct as I have a iyama monitor

Can a mod sort out my link so that people can use it please

[Teegedeck]

Mind your language, chilledoutuk. I know you have been provoked but if the two of you don't manage to keep this discussion civil you're both like to earn a strike. Yes, aspect ratio is a confusing topic where even slightly different usage of terms can create the impression of disagreement, so please...!

BTW, your link works. And thanks for that guide.

[Bassphine]

O.k. while I don't really want to keep this irellevent conversation going i have to put in that you obviously don't know much about PAL and NTSC aspect ratios. PAL and NTSC do not have the same aspect ratios PAL is 5:4 and NTSC is 4:3. So why you keep thinking that 720x576 is 4:3 when it is 5:4 is beyond me.
720x480 does equal a 1.5 aspect ratio you are correct, however it does this for maximum compatibilty for various video sizes that can be played back. To use your example of 1.33 playback yes the DAR flag for 4:3 is raised but only to tell the player that it does not need to squish down or stretch out, it pretty much tells it to do nothing with the video.
If you have ever watched a fullscreen NTSC t.v. show or movie that was put to DVD without cropping the top and bottom to 'fill' the whole screen then you would undoubtedly have noticed that there are bars on either sides of the video. These bars are there because the 1.5 is larger then the 1.33, most dvd players and software automaticaly or have an option for you to 'zoom' the image to remove these bars.

Bassphine

P.S. grow up. The word 'turd' hasn't been used since I was in 4th grade. LOL btw my lil cousin is in 4th grade now and he wouldn't even say that, he's got a colorful imagination.
Teegedeck - I am sorry for this poor display of manners from others in this thread that just don't understand or are misunderstanding what is being stated here. There are many ways of going about or even completely alternative methods to what I have described to achieve a certain result and people seem to like to 'showboat' there methods as being better. I however believe that I have been merely backing my own method as an alternative for people that would like to try something new. I have stated that I perfer this method myself and why I perfer it, however I have not outright stated it as being king like a couple of people have stated with their own methods.
You may delete this thread if you wish as I will no longer be adding updates to it as I had planned, I do not feel as if I need to constantly defend a method that was shown to me by the same people that mastered T3, MIB, Frailty and others. BTW I may be working there as a liason for my company which provides them with their equipment.

[Teegedeck]

OK, Bassphine, as you don't seem inclined, yet, to follow my little hint to get the discussion back to a professional level please show some Christmas spirit in your next post here immediately or you can consider yourself striked! Rule 4 applies, I warned you. I hope chilledoutuk shows more sense - and you, too, from now on .

[chilledoutuk]

everybody hears a little experiment for you to try.

this experiment shows the aspect that software media players resize 4:3 dvd content to which funnily enough should be 4:3 acording to me and the XVID devs.

Playback a 4:3 video dvd pal or ntsc with a dvd player i used both mpc and vlc.

take a screen grab of this screen.

open photoshop or whatever and use the magic wand tool to select the black empty space in the middle of the image.

crop the rest of the image away you are now left with the window that the video was payed back in correct aspect in with the overlay.

take the resolution of the resulting image and divide the width by the height like the image attached.
645/485=1.329896907216494845360824742268

hmm that seems remarkably like the ntsc 4:3 video is actually being resized to 4:3.

I rest my case

Merry christmass :D

[darkavatar1470]

its never been actually 4:3 or 16:9 or whatever anyway...
I always try to find some large round objects in different parts of the clip, crop, resize, draw circles in Photoshop, and try to get something with the width of 1024. reason for upsizing explained very nicely here by Didée
http://forum.doom9.org/showthread.php?p=568512#post568512

this is just yet another matter of personal taste, so calm down pepole.