how to tell aspect ratio such as 1.78:1 without looking at the DVD cover?

[nukesgoboom]

i cropped a 720x480 NTSC into a 720x360 (removed letterboxing) NTSC 29.97 fps dvd into an xvid file and it came out looking good except the aspect ratio was slightly off even though i had done no resizing.

then i learned by looking up the dvd on amazon.com that the movie was filmed in 1.78:1 apsect ratio, and to keep aspect ratio i should have resized from 720x360 post-crop to 720x404. sure enough, it looks better.

is there any way to tell the real aspect ratio without looking up the dvd on amazon? media player classic claims the aspect ratio is 4:3 which is of course WRONG. also media info tool claims AR is 4:3... but its really 1.78:1 (16:9).

in the end, i had to resize to 720x404 to get it looking perfect. but, how else could i have figured out the REAL aspect ratio without looking up the dvd information on amazon? should i just assume that all letterboxed ntsc dvd's are really 16:9? what about 1.85:1 (720x390) and 2.35:1 (720x306)?? ive read those are other 'common' aspect ratios.

please enlighten me!

[CWR03]

Try opening it with AutoGK, then use the Preview function. It's nearly always correct.

The Amazon.com info isn't always accurate anyway. I've seen aspect reported as 16:9 when in fact it was 1.85:1 including the letterboxing.

The only way to be certain is to find a spherical object in the video and resize it so it's round.

[BigDid]

Try opening it with AutoGK, then use the Preview function. It's nearly always correct...
Yes, if AGK is doing the autocrop correctly (active even for preview).

Did

Edit:Rephrasing

[setarip_old]

how to tell aspect ratio such as 1.78:1 without looking at the DVD cover?Despite your specifically limited question, I'd ask you why you don't simply look at your DVD? The AR is also noted on the DVD label (Not just the packaging)...

[soulstace]

http://img446.imageshack.us/img446/6318/devillz6.png

lol

[LocalH]

media player classic claims the aspect ratio is 4:3 which is of course WRONG. also media info tool claims AR is 4:3... but its really 1.78:1 (16:9).
If you had to upsize it to correct the aspect ratio, then it's not "enhanced widescreen" - in other words, it's hard-letterboxed inside a 4:3 frame. Thus, the Pixel Aspect Ratio (PAR) of the source is 4:3 (meaning that each pixel is 4/3 times as wide as it is tall), but with square-pixels, the video frame is 16/9 times as wide as it is tall. Also note that, to be pedantic, your 720x404 video is not exactly 16:9 - 720/404 is 1.7821782 repeating while 16/9 is 1.7777 repeating. This error is negligible, however, and you won't generally notice a difference.

Had the disc been "enhanced widescreen", the video would have most likely taken the entire 720x480 frame.

You only have two PARs to worry about with DVD - 4:3 (such as the disc you reference) and 16:9 (any enhanced widescreen disc). You can tell just by looking at a raw 720x480 frame as if it is square-pixel (load the video into VDub, for instance). If objects are slightly too wide, then it's a 4:3 disc. If objects are way too thin, then it's 16:9.

[nukesgoboom]

i just loaded a .vob into auto gk. i hit alt+f9 for hidden options, checked auto crop, and put 60 crop in top and bottom and clicked preview. after it loaded DGI index it gave me a preview in windows media player 6.4 .

i went to file, properties, details tab, and looked at the video size.

it was 720x400. thats very close to 720x406 (closest you can get to 16:9 with even integers). is that what auto gk meant to say, 720x406? that is the closest even integerXinteger to 16:9 which is considered a 'common' aspect ratio.

does that sound normal? i had fixed width activated: 720. would that affect the preview?

when i crop the letterbox out, and then resize, ill be doing this:

starting 720x480, crop letterbox=720x360, and then resize to 720x406. or should i resize to 720x405, which is exactly 1.77:1 ? the vertical resolution is an odd number, but is that bad? its more accurate than 720x406. xvid can handle any resolution correct?

is this a correct and acceptable way to determine actual aspect ratio, using auto gk this way? final resolution=720x405 after cropping out the letterbox, for 720x480 ntsc 29.97 fps letterbox dvd, identified as 720x400 with auto gk with 60Top 60Bottom crop on?

[BigDid]

i just loaded a .vob into auto gk. i hit alt+f9 for hidden options, checked auto crop, and put 60 crop in top and bottom and clicked preview. after it loaded DGI index it gave me a preview in windows media player 6.4 .

i went to file, properties, details tab, and looked at the video size.

it was 720x400. thats very close to 720x406 (closest you can get to 16:9 with even integers). is that what auto gk meant to say, 720x406? that is the closest even integerXinteger to 16:9 which is considered a 'common' aspect ratio.
and my previous post:
Yes, if AGK is doing the autocrop correctly (active even for preview)
So for someone having read the tutorial or the FAQ, it is evident that AGK does the autocrop without user intervention. Now my sentence was meaned to explain that IF the autocrop is NOT done correctly (still having black bars) the AR will not be accurate. In this case either you crop manually or you raise the threshold (65 to 69 usually works).

...does that sound normal? i had fixed width activated: 720. would that affect the preview?Back to the tutorial again, fixed width will affect the preview.

is this a correct and acceptable way to determine actual aspect ratio, using auto gk this way?..

I just have re-done some tests on a LOTR3 Vob Chunk.
Here are the results:
LOTR3 with auto width:
704*288 = 2.44:1
LOTR3 with 720 fixed width
720*304 = 2.36:1
LOTR3 with manual crop 78+78 and 720width
720*304 = 2.36:1
Using 76+76 or 80+80 leads to the same 304 height.
Using override input AR+ check original+ manual crop 78+78 and 720 width gives
720*416 = 1.73:1 (anamorphic?)

Constant remark: whatever the crop mod, it seems AGK will make it mod16 compliant so AGK may not be a good tool to get the exact AR. Now regarding AR and PAR/DAR or anamorphic, I pass; maybe experienced users will pass by and give some light :)

Did

[CWR03]

The only problem with using an odd resize (or for that matter, a resize that's not an increment of 16) is that you limit what devices can play back the file. If you expect to never have it on anything but a PC, it shouldn't be a problem, but very few standalone players will accept a file that's not MOD16.

Whether or not it's an "acceptable" way depends purely on how the video looks. If things don't look squished or stretched, then it should be fine.

Keep in mind too that 720 x 400 is barely 1% off from the exact proper aspect of 720 x 405, and it should be barely perceptible. 704 x 400 would be closer still, and would also maintain MOD-16.

[nukesgoboom]

im now working on 2001: a space odyssey by stanley kubrick. the ratio appears to be 2.35:1 but whats odd is that there is also some black bars that appear on the sides of the video as well. i had to crop 2 on the left and 6 on the right to get them off. very strange. i had to crop 93 on top and 95 on the bottom to get the letterboxing away.

now i have a 712x292 video. since the ratio is 2:35:1, i could resize to 720x306 but why not just use 712x302, so i dont have to resize horizontally?

this movie was filmed back in 1968, so any softness i see in the video i just attribute it to the age of the camera technology.

however i am using a de-interlacing filter, because its always interlaced after using DGIindex and VFAPIConvEN. nature of the beast, or am i doing something wrong?

should i use a sharpen filter to counter-act the effects of the de-interlacing? (im using area based blending). or is this frowned upon? i usually go with srength: 24.

also i have to say, converting dvd's to xvid takes a long time!! not even considering the vob ripping, my first pass on this movie was almost 5 hours long! any reason its taking so long? however it is a long movie, almost 2.5 hours long.

[BigDid]

... also i have to say, converting dvd's to xvid takes a long time!! not even considering the vob ripping, my first pass on this movie was almost 5 hours long! any reason its taking so long? however it is a long movie, almost 2.5 hours long.
Usually avisynth time-consuming filters :D

Post your script to have confirmation and/or identify the culprit(s).

Did

[CWR03]

2001: A Space Odyssey is 2.20:1.

[manono]

however i am using a de-interlacing filter, because its always interlaced after using DGIindex and VFAPIConvEN. nature of the beast, or am i doing something wrong?

You're doing just about everything possible wrong. You're using the old widescreen 4:3 version as your source, rather than the newer 16:9 version. You're cropping by odd numbers. You're using non-Mod16 resolutions. You're deinterlacing. You're using a VFAPI.

Why not let AutoGK do the job right?

[nukesgoboom]

im using the old widescreen version? are you saying im using an old dvd release of this movie? im not sure what you mean here.

im cropping by odd numbers because i need to get rid of all the blackness. there is more blackness on the left than there is on the right. so i need to crop by only even numbers to keep the aspect ratio right? i can either leave 1 line of blackness or delete 1 line of the movie to get an even number.

i have to de-interlace. when i watched a small clip from one of the .vob files, the footage was interlaced. is this because im using a VFAPI? whats wrong with that?

your saying if i just load the .ifo for the .vobs into auto gk, it will do all of this automtically for me, and output a nice looking, proper aspect ratio xvid file at the end? its really that simple? autogk can actually detect the aspect ratio and auto crop/auto resize the vobs? and it wont have any interlacing? jesus christ! should i use fixed width: 720, or let auto gk decide with the auto-width option?

thanks for all the help.

[LocalH]

i have to de-interlace. when i watched a small clip from one of the .vob files, the footage was interlaced. is this because im using a VFAPI? whats wrong with that?
That sounds like hard telecining (i.e., the telecine was done prior to MPEG-2 encoding and thus the MPEG-2 stream is pure interlaced NTSC, without pulldown flags). You'll need to IVTC that in order to attempt to reconstruct the original 24fps video. As far as I know, AutoGK will do this for you, although you may have to manually enable it (since it doesn't see pulldown flags, it will treat the video as interlaced). Standard deinterlacing is incorrect because it only works within a single frame (although some deinterlacers do use motion vectors to aid in the quality of the deinterlacing), and telecined video has a defined pattern of combed and non-combed frames, and fields must be combined that come from different frames.

[CWR03]

i can either leave 1 line of blackness or delete 1 line of the movie to get an even number.
That's exactly what you do. Are you really going to miss one line of pixels?
i have to de-interlace.
Not if it's film. It may look interlaced, but it's more than likely progressive.
your saying if i just load the .ifo for the .vobs into auto gk, it will do all of this automtically for me, and output a nice looking, proper aspect ratio xvid file at the end?
Yes, AutoGK nearly always gets the aspect correct, and does a good job of deciding on the encoding properties, but you can (if you do it right) get a better output with the full Gordian Knot or VirtualDub.
should i use fixed width: 720, or let auto gk decide with the auto-width option?
You ask a lot of "should I's" when they can't be answered with limited information. Whether or not you should use fixed width depends hugely on the file's run length, vertical resolution and your selected file output size. For example, if you select a fixed width of 720 and encode 2-pass, you need to estimate backwards to determine the filesize output that will yield an acceptable bitrate. In that example you'd need a large output file size to maintain quality. If you lock in 720 width and shoot for 1 CD with 2001: A Space Odyssey, it's gonna look like hell.

Edit: Before you ask, the only way to estimate backwards to determine filesize is by trial and error, and finding settings for your output that suits your perception.

[nukesgoboom]

ah, so telecining is the reason. thanks for informing me. ill try to search for the IVTC option in the alt+f9 menu. i wont use normal de-interlacing.

i will use auto-gk with 'auto-width' mode, and also the IVTC option if i can find it. i would never shoot for 1 cd because 2001: a space odyssey is almost 3 hours long. ill ask auto gk for a 1400 mb file.

auto gk was the answer after all. doing it by hand has proven a formidable task.

[ricardo.santos]

how to tell aspect ratio such as 1.78:1 without looking at the DVD cover?

theres a tool called "Aspect" that will tell you the aspect ratio
http://forum.doom9.org/showthread.php?p=784550#post784550

[mod]

I'm writing a little tool that could help you. Make a .d2v file, open it, autocrop (or get values from .d2v file) and calc: you'll get the real MAR of the video and all the suggested resolutions (works like Aspect but the error is minimal). The main reason I started writing it was to encode with the right AR, so I hope it helps :)

here (http://forum.doom9.org/showthread.php?t=112808)

[manono]

ah, so telecining is the reason. thanks for informing me. ill try to search for the IVTC option in the alt+f9 menu.

AutoGK will analyze it and do what has to be done. Don't gum up the works by trying to "guide" it.

im using the old widescreen version? are you saying im using an old dvd release of this movie? im not sure what you mean here.

Yes, there are 2 R1 versions of the film. Well, there are 3 actually, but 2 use the same widescreen 4:3 master. The original is widescreen, non-anamorphic 4:3, (no longer available at retail), and is soft looking because of that. The resolution is lacking. It also has other problems, including dark, dingy colors and edge enhancement. The newer 16:9 version is much better.

4:3: http://www.imdb.com/title/tt0062622/dvd#630504743X
4:3: http://www.imdb.com/title/tt0062622/dvd#B00000J2KP
16:9: http://www.imdb.com/title/tt0062622/dvd#B00005ASUM

Here's a comparison of the differences between the 1998 4:3 MGM version, and the 2001 Remastered 16:9 Warner version (with a PAL R2 version thrown in as well):

http://www.dvdbeaver.com/film/DVDCompare6/2001.htm

I deduced you had the older widescreen 4:3 version because you said you had to crop down to 712x292 to get rid of all the black.

[CWR03]

ah, so telecining is the reason. thanks for informing me. ill try to search for the IVTC option in the alt+f9 menu.
To reiterate, 2001: A Space Odyssey, in addition to nearly all films on DVD, is not telecined.
i would never shoot for 1 cd because 2001: a space odyssey is almost 3 hours long.
It was merely an example, albeit an extreme one. You actually could encode that movie to 700MB, but if you do and let it select its own width it'll output at a very small resolution.

[bkman]

theres a tool called "Aspect" that will tell you the aspect ratio
http://forum.doom9.org/showthread.php?p=784550#post784550

You can also use my little tool which no-one seems to have noticed: http://forum.doom9.org/showthread.php?t=113643

[laserfan]

Here's a comparison of the differences between the 1998 4:3 MGM version, and the 2001 Remastered 16:9 Warner version...Having seen 2001 over 100 times in the theater (!) and having acquired all home video versions that I could find, from the scan/pan VHS tape thru Japanese LD to the 4:3 MGM DVD in 1998, I finally burned-out on the thing.

But your link has inspired me again--I guess I have to get the Warner remaster for my collection. Hopefully an HD version will not be too much longer in coming... Thanks (I think!) for your post!

[CWR03]

laserfan, I don't know which DVD version of 2001 it was that I recently rented from Netflix, but it was a very good DVD transfer - no "loose sprocket" film shaking, scratches or anything. They even had the proper 2.20:1 aspect. The 2010 transfer wasn't the same at all.