Sample Aspect Ratio calcutions

[kotrtim]

Source/Encoded Resolution ( X:Y )
Desired Display Resolution/Aspect Ratio ( H:V )

The formula to calculate PAR/SAR

Y ÷ X ÷ V x H = SAR fraction

for example a NTSC 16:9 with resolution 720:480

480 ÷ 720 ÷ 9 x 16 = 1.185185185... (32/27)
therefore the Sample Aspect Ratio that should be keyed in in MeGUI is 32x27

for NTSC 4:3 with resolution 704:480
480 ÷ 704 ÷ 3 x 4 = 0.88888...(10/11)
SAR = 10x11

CROPPING without resizing
won't affect the SAR

Any comments on the way I calculate SAR?
I took quite some time to understand that
SAR is actually the ratio of every single pixel..not
the ratio displayed by the video frame

[yaz]

@kotrtim
the way u derive (s)ar is ok but why do u use different vertical resolutions for the 4/3 and for the 16/9 streams. maybe it's ok (i'm living in the pal world :) ) just ask.

however, the values calculated
- for ntsc 720 x
4:3 64:72 (8:9)
16:9 64:54 (32:27)
- for ntsc 704 x
4:3 10:11
16:9 16:11

the bests
y

[Raithmir]

Cropping will change the SAR, at least thats what I was told in the similar thread I posted. This comment might be of use, I saved it and use this calculation...

"The actual way meGUI calculates the SAR is as follows:
1) Apply the cropping and then determine the aspect ratio of the input video image (inputPixelCountRatio).
2) Scale the vertical resolution according to the horizontal resolution that's been specified (resizedVerticalResolution = horizontalResolution / inputPixelCountRatio)
3) Adjust the vertical resolution so that it matches the closest multiple of 16.
4) Set SARX to the horizontal resolution.
5) Set SARY to Round(HorizontalResolution^2 / (VerticalResolution * DAR)), this is then truncated to an integer."

So if you're not resizing you can ignore 1-3 and use the horizontal and vertical resolution after you've cropped.

[Raithmir]

http://forum.doom9.org/showthread.php?t=104485

Some confusing information at first but read the whole thread.

No doubt someone else will come along and tell me it's all wrong and I'm doing it incorrectly again.

[kotrtim]

My opinion is SAR won't change after cropping as you crop off pixels, and SAR is the ratio of every pixel, so the value of SAR should not change whereas the DAR will change as DAR is the measurement of the whole frame, when you croped, the frame size definitely changes.

If we want to resize, why not just resize so that it is 1:1, of course this is just my opinion

[bkman]

My opinion is SAR won't change after cropping as you crop off pixels, and SAR is the ratio of every pixel, so the value of SAR should not change whereas the DAR will change as DAR is the measurement of the whole frame, when you croped, the frame size definitely changes.

For me this brings up the question of what is the true DAR of a DVD source. Ie. If you have what used to be a T.V. program, which as we know is 4:3 (right?), but it has black bars on the side and the resulting AR after cropping them off is not 4:3, what do you do then? Use the bar-less DAR when calculating the SAR, or use the DAR with bars included, or just use the 4:3 DAR that you know it must be as a T.V. source? Quite confusing. For that matter, how is 720x480 4:3??

[yaz]

cropping does not change the way of derivation (resizing). if u crop the stream (sar) u 'crop' also what u get on the display (dar). u'd better think of it as 'how to distort each pixel so as to get the right aspect ratio on the display'.

say, u got a pal 4:3 dvd. its stream size is 720x576 (by def) which is 5/4 ratio. it must be displayed 4/3 so as to get the correct ratio on the display, so, it must be resized to 768x576. it is the same as displaying each pixel in a 16x15 rectangle instead of a 15x15 square (measured in whatever unit).
if u crop it to 704x576 (for any reason) it must be resized the same way, so the display size must be ~751x576. otherwise the picture on the display will be distorted.

it's simple as that ;)

the bests
y

[bkman]

But why is it that the "true" DAR includes black bars? Surely they are not part of the actual image, and it should be resized to 4:3 without them. Like if you cropped to 704x576 to give the full image, shouldn't that then be resized to 768x576 (instead of 751x as with counting the black bars) to give proper AR since the original T.V. show was 4:3 (and had no black bars originally)?

[SeeMoreDigital]

If you can guys, try and calculate "everything" as a fraction, because converting fractions to decimals and back to fractions again "can" produce conflicting Aspect Ratio Signalling (ARS) values.

If your NTSC movie has an aspect ratio of 1.33:1, then this can be represented as a fraction of 4/3. Meaning: -

4 480 1920 8
- x --- = ---- lowest dominator - Giving an ARS value of 8:9
3 720 2160 9

If your NTSC movie has an aspect ratio of 1.77:1, then this can be represented as a fraction of 16/9. Meaning: -

16 480 7680 32
-- x --- = ---- lowest dominator -- Giving an ARS value of 32:27
9 720 6480 27

If your NTSC movie has an aspect ratio of 1.85:1, then this can be represented as a fraction of 37/20. Meaning: -

37 480 17760 37
-- x --- = ----- lowest dominator -- Giving an ARS value of 37:30
20 720 14400 30

If your NTSC movie has an aspect ratio of 2.35:1, then this can be represented as a fraction of 47/20. Meaning: -

47 480 22560 47
-- x --- = ----- lowest dominator -- Giving an ARS value of 47:30
20 720 14400 30

If your NTSC movie has an aspect ratio of 2.40:1, then this can be represented as a fraction of 12/5. Meaning: -

12 480 5760 8
-- x --- = ---- lowest dominator - Giving an ARS value of 8:5
5 720 3600 5


For working out the "Aspect Ratio Signalling" values of PAL sources, simply substitute 480/720 to 576/720 and recalculate.

The same formula can be used to work out the "Aspect Ratio Signalling" values of cropped and re-sized encodes too by entering the relevant resolutions.


Cheers

[bkman]

The same formula can be used to work out the "Aspect Ratio Signalling" values of cropped and re-sized encodes too by entering the relevant resolutions.

See, that is what I have been doing, but what yaz says seems to contradict this.

So that is the question that I haven't seen everyone agree upon: If you have a movie/show that you "know" the aspect ratio of (16:9, 4:3, etc) but it has black bars which need to be cropped, do you a.) Use the cropped size in your SAR calculation, or b.) Use the original size before cropping?

[SeeMoreDigital]

So that is the question that I haven't seen everyone agree upon: If you have a movie/show that you "know" the aspect ratio of (16:9, 4:3, etc) but it has black bars which need to be cropped, do you a.) Use the cropped size in your SAR calculation, or b.) Use the original size before cropping?What I do is establish the aspect ratio of the source movie. The popular "Movie Aspect Ratio's" (MAR's) are, 1.85:1, 2.35:1, 2.40:1

All MAR's can be converted to a fraction. For example: -
1.85:1 works out at 37/20
2.35:1 works out at 47/20
2.40:1 works out at 12/5

The MAR value can then be placed into the equation like this: -

MAR FAR ARS
47 368 17296 1081
-- x --- = ----- lowest dominator ---- Giving an ARS value of 1081:900
20 720 14400 900

Which can be further simplyfied by converting: -

1081 1080 6
---- to ---- lowest dominator - Giving an ARS value of 6:5
900 900 5


Cheers

[bkman]

Well, yes I understand that, but it doesn't really answer my question about how to deal with DVD's that require cropping off the black bars.

Another related question is: Why are the padding bars even there on the DVD? Are they part of the original image as it was meant to be displayed or just artifacts of DVD conversion? Answering this will answer the first question also.

[yaz]

But why is it that the "true" DAR includes black bars? Surely they are not part of the actual image, and it should be resized to 4:3 without them.definitely not. really, black bars are not part of the movie but they are part of the image/stream. they are used to maintain the stream dimensions which must(!) be always 720x576 for pal dvd and 720x480 for ntsc dvd. whithin this fixed-size box u can place any stream having quite arbitrary dimensions. (say, 654x321 is ok, if its 'bordered' to 720x576/480)
this box is resized during the playback according to the 'par' value (which simply defines how much it should be streched horizontally) calculated as showed above.

don't ask me why is it figured out like this but that's what we have ;)

Like if you cropped to 704x576 to give the full image, shouldn't that then be resized to 768x576 (instead of 751x as with counting the black bars) to give proper AR since the original T.V. show was 4:3 (and had no black bars originally)?hmm ... can't get u here, but ... the stream must be shown 4/3 on your screen/display/tv but how it's stored in a file/dvd/whatever depends on the intention of the creator. there are possibilities (see above).
about the borders ... maybe they just cut away some dirty/bleeding/shifted/ringing/... pixels round the pictures for getting better compression. dunno

the bests
y

[SeeMoreDigital]

Well, yes I understand that, but it doesn't really answer my question about how to deal with DVD's that require cropping off the black bars.When you crop away the black mattes from a DVD source, the important thing is too make sure you end up with horizontal and vertical resolutions that are in multiples of 16 pixels (aka: "mod16").

However, because this is not always possible with cropping alone, you may end up having to re-size the image slightly until you obtain a "mod16" frame size.

In theory, it is possible to display an encode at any shape you want, once the required AR signalling value has been applied.

Another related question is: Why are the padding bars even there on the DVD? Are they part of the original image as it was meant to be displayed or just artifacts of DVD conversion?The black mattes are there because that is what was agreed upon and later defined within the MPEG-2 DVD standard.

It was decided that the most effective way of displaying images with different aspect ratios was to overlay the "image portion" onto a "black background portion" (aka: matte) with a fixed Frame Aspect Ratio (FAR). So this is why all commercial PAL DVD's have an fixed FAR of 720x576 or 5/4. All commercial NTSC DVD's have a fixed FAR of 720x480 or 3/2.

Hope that helps.... a bit ;)

[bkman]

Hmm, I'm still not quite satisfied with an answer, so let me phrase the question in another way with an example case:

You have T.V. show on an NTSC DVD. The video has 8 pixels of black padding on either size, so you crop them off and are left with a resolution of 704x480. What SAR would you set in this case? 10:11? 8:9? Something else?

[SeeMoreDigital]

Hmm, I'm still not quite satisfied with an answer, so let me phrase the question in another way with an example case:

You have T.V. show on an NTSC DVD. The video has 8 pixels of black padding on either size, so you crop them off and are left with a resolution of 704x480. What SAR would you set in this case? 10:11? 8:9? Something else?If you followed the formula I provided you would be able to work it out....


MAR FAR ARS
4 480 1920 10
- x --- = ---- lowest dominator -- Giving an ARS value of 10:11
3 704 2112 11


I'm presuming the source is intended to be displayed at 4:3?

[kotrtim]

Well, yes I understand that, but it doesn't really answer my question about how to deal with DVD's that require cropping off the black bars.

I would say use the original size for calculations, because SAR is the heightXwidth of every little pixel, cropping off the black bars won't affect

lets say you have a pice of paper, 100 cm long, 10 cm width, you divide eqaully into 10 cells (similar to pixels), of course 100/10 = 10cm, therefore each box is 10cm x10cm, the sample ratio is 1x1, now cut off one cell, the piece of paper is now 90cm long, 10cm width, but the ratio of each cell is still 1x1, it never change, you can still use the previous equation 100/10 = 10cm , not 90/10.....

but for DAR, it is changed, before you cut, DAR is 100x10, after you cut it is 90x10

This is what I understand about cropping without resizing, hope you can imagine what i'm trying to tell

[SeeMoreDigital]

kotrtim,

I think you are thinking about "square" pixels and not "anamorphic" (aka: non square) pixels.

Do you understand the differences?


Cheers

[nm]

I agree with kotrtim here. Your formula doesn't apply directly because 4:3 is _not_ the movie aspect ratio of the cropped image. However, the SAR doesn't change when cropping.

[bkman]

I'm presuming the source is intended to be displayed at 4:3?

Good question. How would you know definitively? Are all NTSC Television sources 4:3? If so, why the padding bars?

[kotrtim]

Good question. How would you know definitively? Are all NTSC Television sources 4:3? If so, why the padding bars?

A DVD can either have 4:3 or 16:9 , but sometimes movies are made with aspect different from the two above, something like 235:100, it does not fit 4:3 or 16:9 , therefore black bars are added to make it 4:3/16:9, besides that the original ratio of the film can be preserved

[bkman]

A DVD can either have 4:3 or 16:9 , but sometimes movies are made with aspect different from the two above, something like 235:100, it does not fit 4:3 or 16:9 , therefore black bars are added to make it 4:3/16:9, besides that the original ratio of the film can be preserved

But 720x480 is not 4:3 or 16:9. Do you mean that DVD can only support 4:3 or 16:9 AR signalling?

[SeeMoreDigital]

A DVD can either have 4:3 or 16:9 , but sometimes movies are made with aspect different from the two above, something like 235:100, it does not fit 4:3 or 16:9 Ofcourse they do. This is what the subject of anamorphic images is all about.

As I mentioned before, a movie with an aspect ratio of 2.35:1 can be represented as a fraction of 47/20 (ie: 47 divided by 20 equals 2.35). Which can be worked into the formula I provided.


Cheers

[SeeMoreDigital]

I get the impression that you guys are trying to "run" before you can "walk".

You really must do some reading up on what "uncorrected" anamorphic images look like...

What I mean be "Uncorrected" is, what the image looks like before any form of aspect ratio signalling has been applied, whether it be SAR, PAR or DAR!


Cheers

[kotrtim]

I've never seen any DVD with 47/20, I've film with 2.35:1 which has added black bars to make it 4:3

Do you mean that that DVD-video standard can have any fraction of aspect ratio besides 4:3 and 16:9?

Does anamorphic means the pixels are displayed rectangularly instead of squares?

[bkman]

I get the impression that you guys are trying to "run" before you can "walk".

You really must do some reading up on what "uncorrected" anamorphic images look like...

What I mean be "Uncorrected" is, what the image looks like before any form of aspect ratio signalling has been applied, whether it be SAR, PAR or DAR!


Cheers

Well, I've just read http://www.doom9.org/index.html?/aspectratios.htm and its has plugged some of the gaps in my knowledge.

"Uncorrected" anamorphic images are 720x480 (for NTSC) with the aspect ratio of 1.5:1, right?

And the DAR can be set to signal stretching to either 4:3 or 16:9 (and two others). But, going back to my example case earlier, if the source was in fact 4:3 then the DAR would be set to that, and there should be no padding borders. So why are there borders? My only conclusion is that the original source is NOT 4:3 but rather 176:135, and the borders are there to correct the aspect ration from 4:3! So it seems to me that kotrtim has the right of it, and that I should use the uncropped size for SAR calculation.

Do you agree with my reasoning, SeeMore? Or ir there yet more that I don't correctly understand.

Edit: Correction.

[SeeMoreDigital]

"Uncorrected" anamorphic images are 720x480 (for NTSC) with the aspect ratio of 1.5:1, right?Yep that's correct!

And the DAR can be set to signal stretching to either 4:3 or 16:9 (and two others). But, going back to my example case earlier, if the source was in fact 4:3 then the DAR would be set to that, and there should be no padding borders. So why are there borders? My only conclusion is that the original source is NOT 4:3 but rather 176:135, and the borders are there to correct the aspect ration from 4:3! So it seems to me that kotrtim has the right of it, and that I should use the uncropped size for SAR calculation.Yes the are two DAR levels for commercial 4:3 and 16:9 NTSC DVD's. There are also two DAR levels for commercial 4:3 and 16:9 PAL DVD's.

The padding (borders) which can often be seen to the left and right of DVD images is (arguably) there to help reduce "over-scan". Normally when playing DVD's via a stand-alone player and viewing them via a TV, you would not see this padding but on a PC you do.

But even if you crop away the left and right padding boarders, the "target" aspect ratio shape is still indended to be either 4:3 or 16:9.


Cheers

[bkman]

The padding (borders) which can often be seen to the left and right of DVD images is (arguably) there to help reduce "over-scan". Normally when playing DVD's via a stand-alone player and viewing them via a TV, you would not see this padding but on a PC you do.

That would explain a lot, but as you say it is arguable and may not always be the case. So there is a choice when calculating the SAR in that respect, I think, where some might think it is more correct to do it one way, and others the other.

Thanks for your help with my questions, btw.

[SeeMoreDigital]

That would explain a lot, but as you say it is arguable and may not always be the case. So there is a choice when calculating the SAR in that respect, I think, where some might think it is more correct to do it one way, and others the other.

Thanks for your help with my questions, btw.When you read my posts you will see I tend not to mention terms such as SAR, PAR and DAR. This is because people tend to pre-assume their values are always "fixed".... Which they are not!

The level of "Aspect Ratio Signalling" (ARS) you will require will change in relation to your source "Movie's Aspect Ratio" (MAR) and your "mod16" pixel frame size (after cropping and resizing).

Here's an "extreme" example of what I mean. If you had an MPEG-4 file with say, a resolution of 496x464 but you knew it should be displayed at 2.35:1 shape, you could use the following calculation: -

MAR FAR ARS
47 464 21808 1363
-- x --- = ----- lowest dominator ---- Giving an ARS value of 1363:620
20 496 9920 620

EDIT: I forgot to include the "Extreme Example" (http://81.98.148.105/Uploaded_Files/Doom9_Forum_files/Extreme_ARS_Example.7z) sample.


Cheers

[DigitalDivide]

Not being the best at math, is there any easy way to work out the lowest common denominator? Is it possible to enter in 1920:2112 as the SAR in MeGUI or must I absolutely break it down further?

[DigitalDivide]

If you can guys, try and calculate "everything" as a fraction, because converting fractions to decimals and back to fractions again "can" produce conflicting Aspect Ratio Signalling (ARS) values.

If your NTSC movie has an aspect ratio of 1.33:1, then this can be represented as a fraction of 4/3. Meaning: -

4 480 1920 8
- x --- = ---- lowest dominator - Giving an ARS value of 8:9
3 720 2160 9

If your NTSC movie has an aspect ratio of 1.77:1, then this can be represented as a fraction of 16/9. Meaning: -

16 480 7680 32
-- x --- = ---- lowest dominator -- Giving an ARS value of 32:27
9 720 6480 27

If your NTSC movie has an aspect ratio of 1.85:1, then this can be represented as a fraction of 37/20. Meaning: -

37 480 17760 37
-- x --- = ----- lowest dominator -- Giving an ARS value of 37:30
20 720 14400 30

If your NTSC movie has an aspect ratio of 2.35:1, then this can be represented as a fraction of 47/20. Meaning: -

47 480 22560 47
-- x --- = ----- lowest dominator -- Giving an ARS value of 47:30
20 720 14400 30

If your NTSC movie has an aspect ratio of 2.40:1, then this can be represented as a fraction of 12/5. Meaning: -

12 480 5760 8
-- x --- = ---- lowest dominator - Giving an ARS value of 8:5
5 720 3600 5


For working out the "Aspect Ratio Signalling" values of PAL sources, simply substitute 480/720 to 576/720 and recalculate.

The same formula can be used to work out the "Aspect Ratio Signalling" values of cropped and re-sized encodes too by entering the relevant resolutions.


Cheers

Just to be clear so I would enter in the ARS values indicated above as the SAR in MeGUI?

[DigitalDivide]

So for my 2.35 NTSC DVD
after cropping
47 368 17296
-- x --- = ----- which breaks down to ? This us entered as SAR in MeGUI
20 704 14080

Is this correct?

[SeeMoreDigital]

So for my 2.35 NTSC DVD
after cropping
47 368 17296
-- x --- = ----- which breaks down to? This us entered as SAR in MeGUI
20 704 14080

Is this correct?Yes... Initially this would provide an ARS of 1081:880.

However, this could be further converted to say: -

1080 27
---- which, in turn decimates to --
880 22


That said, 199:162 would be more exact :)


Cheers

[DigitalDivide]

Yes... Initially this would provide an ARS of 1081:880.

However, this could be further converted to say: -

1080 27
---- which, in turn decimates to --
880 22


That said, 199:162 would be more exact :)


Cheers

SMD,

Is there a formula as to how to work out the lowest common den? Is it just guess work with a calculator? Give me something to go on..lol :confused:

[SeeMoreDigital]

SMD,

Is there a formula as to how to work out the lowest common den? Is it just guess work with a calculator? Give me something to go on..lol :confused:I use a Sharp EL-530V calculator to work out and simplify all these fractions.... But I'm thinking about developing a little "ARS Calculator" tool... Something like this: -

http://img482.imageshack.us/img482/8163/arscalculatorc8zd.png


EDIT: Here's a 2.35:1 video sample (http://81.98.148.105/Uploaded_Files/Doom9_Forum_files/704x368_at_2.35.1.zip), with a pixel frame size of 704x368 and aspect ratio sigalling at 199:162.


Cheers

[DigitalDivide]

You should definitely create that ARS calculator. It would definitely help a lot and I'm sure everyone would appreciate it.

[iceborne]

i second that

[berrinam]

Just to be clear so I would enter in the ARS values indicated above as the SAR in MeGUI?
Nu-uh! MeGUI now uses what what SMD refers to as Movie Aspect Ratio everywhere. So the only values you will ever really need to know are 4:3, 1:1, 16:9, 47:20 (2.35) and 37:20 (1.85). MeGUI just does all the calculations that SMD described, but behind your back so that you don't have to see them.

You should definitely create that ARS calculator. It would definitely help a lot and I'm sure everyone would appreciate it.
Maybe you could try MeGUI's new system first? It should do all the calculations that SMD's does.

[Wilbert]

SMD likes to stick to non-standard terminology. I think his MAR is the playback AR (after cropping away the black borders). If that's the case, than in many cases you don't know the MAR in advance, unless it is specified on the box of the dvd.

[yaz]

You should definitely create that ARS calculator. It would definitely help a lot and I'm sure everyone would appreciate it.
yep ... such kinda 'calculators' are still released. one of the most known is called Gordian Knot. just give it a try ! well fitted to your dvd resizing problems.

the bests
y

[SeeMoreDigital]

yep ... such kinda 'calculators' are still released. one of the most known is called Gordian Knot. just give it a try ! well fitted to your dvd resizing problems.

the bests
yCan anyone confirm....

Are you able to use the GK and MeGUI "calculators" outside of their applications?

[berrinam]

Not MeGUI.

[yaz]

@seemoredigital
don't feel offended either off-handed, pls ! i just meant by the quotation marks that cropping/resizing are integral part(s) of some well developed applications.
if u (or someone) find such culculator usuful, pls, go on !

the bests
y

[SeeMoreDigital]

@seemoredigital
don't feel offended either off-handed, pls ! i just meant by the quotation marks that cropping/resizing are integral part(s) of some well developed applications.
if u (or someone) find such culculator usuful, pls, go on !

the bests
yNo I'm not offended at all... far from it ;)

As I don't use GK, I don't know what features it offers its users. Embedded or external.


Cheers

[SeeMoreDigital]

SMD likes to stick to non-standard terminology. I think his MAR is the playback AR (after cropping away the black borders). If that's the case, than in many cases you don't know the MAR in advance, unless it is specified on the box of the dvd.Yes.... MAR (Movie Aspect Ratio) is the term I'm proposing we adopt to refer to the aspect ratio of the original source.

After looking at the back of a few DVD cases I've found several other expressions, such as: Original Theatrical Presentation, Original Theatrical Exhibition, Presented in x.xx:x, TV Aspect Ratio.


Cheers

[DigitalDivide]

Nu-uh! MeGUI now uses what what SMD refers to as Movie Aspect Ratio everywhere. So the only values you will ever really need to know are 4:3, 1:1, 16:9, 47:20 (2.35) and 37:20 (1.85). MeGUI just does all the calculations that SMD described, but behind your back so that you don't have to see them.


Maybe you could try MeGUI's new system first? It should do all the calculations that SMD's does.


What version of MeGUI does this? I am currently using version 2.3.1024. Can I simply enter in these values for SAR in the version of MeGUI I am using?

Also I'm unsure when I would use 16:9 rather than 47:20 or 37:20? Is 16:9 for letterbox or nonanamorphic movies?

[berrinam]

What version of MeGUI does this?0.2.3.2059.Your version is very old, and you are missing many good new features. Unfortunately, no new builds are being put on SourceForge for the moment, so you'll have to head over to ChronoCross's builds. There's a link to them at the top of the MeGUI Guide, which is a sticky in the Mpeg-4 Encoder GUIs forum.

Also I'm unsure when I would use 16:9 rather than 47:20 or 37:20? Is 16:9 for letterbox or nonanamorphic movies?They all mean something different. It depends on the AR of your source. If you use the new MeGUI AviSynth Script creator, it should also tell you the correct value (updated also in 0.2.3.2059).

[SeeMoreDigital]

Also I'm unsure when I would use 16:9 rather than 47:20 or 37:20? Is 16:9 for letterbox or nonanamorphic movies?16:9 as a fraction, equates to 1.777:1 as a decimal
47:20 as a fraction, equates to 2.35:1 as a decimal
37:20 as a fraction, equates to 2.40:1 as a decimal

All the above (fractions and decimals), represent the original movies aspect ratio. Which can be found on the back of the original DVD case ;)


Cheers

[jmk]

what i have encountered now a couple of times is, that the ratio on the back of the dvd cover had nothing to do with the actual ratio of the picture without the black borders.

@berrinam: somehow, the values megui reports and writes into the avs file have little to do with the values that i would put in (and which i believe to be correct) into the fields of, what megui calls "sample aspect ratio _ x _" (i tried with te most recent version .2065)

i believe my little tool gives the correct values: http://forum.doom9.org/showthread.php?t=106929

so long,
jmk

[SeeMoreDigital]

what i have encountered now a couple of times is, that the ratio on the back of the dvd cover had nothing to do with the actual ratio of the picture without the black borders.Very rarely though!

With Blade Runner for example. When you play this DVD in a software media player (such as Media Player Classic) and take a "full screen" capture you will see this: -

http://img211.imageshack.us/img211/4774/bladerunnersource8mu.th.jpg (http://img211.imageshack.us/my.php?image=bladerunnersource8mu.jpg)

As you can see both the horizontal and vertical mattes are very poor indeed :scared:

However, when you hard crop the mattes away from the above image you will see this -

http://img223.imageshack.us/img223/3518/bladerunneraftercropping6sr.th.jpg (http://img223.imageshack.us/my.php?image=bladerunneraftercropping6sr.jpg)

And when you divide 968 pixels by 414 pixels you get aspect ratio of 2.338 to 1 (2.338:1).

Which is only 5 "horizontal" pixels away from 2.35:1. Or just 2 "vertical" pixels away from 2.35:1


Cheers