Aspect Ratio Signalling (ARS) Calculation Tool

[kotrtim]

I use vdub because vdub can tell me the frame number,

Can MPC capture the exact frame?

[SeeMoreDigital]

Sadly no... But you can navigate to close to where you want to and then use the step forward button... this is what I do!

But for my purposes I'm just trying to establish the actual aspect ratio of the movie.


Cheers

[kotrtim]

http://img161.imageshack.us/img161/6871/ori4kw.jpg

http://img163.imageshack.us/img163/5685/7203688md.jpg

http://img391.imageshack.us/img391/1714/7202945kp.jpg

the image should self explain

[SeeMoreDigital]

Hi Kotrtim,

May I as how you captured the 720x480 (top) still from your source?

It's quite unusual as it posseses a two pixel wide grey border running along the entire left side and a one pixel high grey border running along the top... Plus the top and bottom mattes are nowhere near equal in size!

Please PM me if you need to?


Cheers

[jv_guano]

Please Note
At the time of writing both applications require Micro$oft's .NET Framework (version 2) in order to run.

I downloaded your ARS calculator, (and also the mpeg4 modifier) but yours doesn't work..it says that I shoulda have one of those versions of net framevork 2.0.50727

so i went here (http://msdn.microsoft.com/netframework/downloads/updates/default.aspx#.NET%20Compact%20Framework%202.0%20Downloads) and downloaded the vers 2.0 ..but still don't work.. :( i also reboot PC after installing framework, and still don't work...
instead MPEG4 modifier works...

any hints?
(hope not to be too much OT...:confused: )

[Doom9]

your link goes to the compact framework downloads.. they are useful for PDAs but not regular PCs. You need this redistributable: http://www.microsoft.com/downloads/details.aspx?FamilyID=0856eacb-4362-4b0d-8edd-aab15c5e04f5&DisplayLang=en

[jv_guano]

your link goes to the compact framework downloads.. they are useful for PDAs but not regular PCs. You need this redistributable: http://www.microsoft.com/downloads/details.aspx?FamilyID=0856eacb-4362-4b0d-8edd-aab15c5e04f5&DisplayLang=en

thanx a lot, it works!

lots of questions are coming soon! :D

-------

so, How do I use the ARS Calculator?
First: You need to determine the "Pixel Frame Size (PFS) of your MPEG-4 encode.
Second: You need to determine the actual aspect ratio of the movie. Known as the, "Movie Aspect Ratio" (MAR). This can often be found on the back of the DVD cover, or on Amazon.
Third: You enter both these values into the "ARS Calculator" and then press the "Calculate" button to obtain the required "Aspect Ratio Signalling (ARS) value.

1)the pixel frame size is the size of a snapshot of the movie? with or without the black mattes?
I really have to say that I have some doubts..also beacause I read somewhere that pixel of movies for tv and pixel of PC images are not the same (the first, rectangular, the second, square)
(what i mean is what you can see in this post (http://forum.doom9.org/showthread.php?p=784256#post784256). the res of the image is not the res of the video...)
Infact, if I snapshot the movie I'm analyzing, I've an image (without black mattes) of 1365*576, instead, loading it in DVDPAtcher, it says 720*576 .. :confused:

and that's all by now... :)

[SeeMoreDigital]

1)the pixel frame size is the size of a snapshot of the movie? with or without the black mattes?It's easier to correct the aspect ratio of an MPEG-4 source if it has no mattes. But it depends on how you've encoded it.

After reading some of the e-mails and PM's I've received it's become quite clear, some of you have generated some very peculiar shaped encodes....

Indeed, when generating "cropped and resized" encodes, some of you have elected to keep tiny bits of the black mattes in..... very strange!


I really have to say that I have some doubts..also beacause I read somewhere that pixel of movies for tv and pixel of PC images are not the same (the first, rectangular, the second, square)I think you may be confusing the pixel frame size of say, a typical DVD source "before image correction is applied" and the pixel frame size of that same DVD source "after image correction is applied".

In-fact, if I snapshot the movie I'm analyzing, I've an image (without black mattes) of 1365*576, instead, loading it in DVDPAtcher, it says 720*576 .. :confused:Do you by any chance have a 16:9 shaped PC monitor set to a resolution of 1365x768 (or there-abouts)?


Cheers

[jv_guano]

Do you by any chance have a 16:9 shaped PC monitor set to a resolution of 1365x768 (or there-abouts)?


Cheers
No, I have a 17" LCD monitor, 1280*1024 res...

by the way, I really appreciated your help, many thanks!

But I've just found a page in my own language (italian, here (http://www.benis.it/dvd/aspect/aspect.htm) if someone's interested) and really hope to solve all of my doubts!

Many thanks again!;)

[SeeMoreDigital]

No, I have a 17" LCD monitor, 1280*1024 res...Now I'm confussed...

I don't know how you were able to snapshot an image of 1365x576 pixels, when your monitor is set to a resolution of 1280x1024 :eek:


Cheers

[jv_guano]

i send ya a screenshots, wait a bit! :)

http://img431.imageshack.us/img431/5636/vlcsnap760759yt.th.png (http://img431.imageshack.us/my.php?image=vlcsnap760759yt.png)

[SeeMoreDigital]

Out of interest....

Can you explain, what player you used, exactly how you captured that image and what the source file is?


Cheers

[jv_guano]

really, maybe I'm wasting your time!

I thought this video would come out too wide on my tv. But, yersterday night, after reauthoring it and burnin' it, I must say (and I really cannot explain to myself "why?" ) this video looks nice and proportionated! ;)

however, I use Vlc , and used the function snapshots in vlc. the source file is a remuxed vob file (I added subtitles)

instead, now I'm going to (try) cutting some video in 4:3 format, to displat and fit well on my 16:9 TV...Those vids have black mattes on top&bottom, so, let's give a try! ;)

(still dvd, and I'm not really so convinced on what sw to use.. :confused: I see mpeg4modifier can only handle *avi files... )

[SeeMoreDigital]

The aspect ratio of your encode does not look right to me....

I'm just guessing but I'm sure it should look more like this: -

http://img374.imageshack.us/img374/3884/1024x5766cd.th.jpg (http://img374.imageshack.us/my.php?image=1024x5766cd.jpg)


Cheers

[jv_guano]

I know that is really not right, but, as I say, burning it on a dvd, it'll display correct on my TV .. :confused:

(don't know why, but those aspect ratios are really hurting myself, and sometimes I stop myself to try to understand... :) )

[mod]

We have entered the 4th page.. so after all this posting I have a question.
My backup method is this, I just want to know if in your opinion the result is a correct aspect ratio of the picture when it's displayed on a 4:3 tv:

1 - make d2v file with DgIndex
2 - open it with Aspect
3 - crop the black I don't want (all cropped selections multiple of 2): Aspect returns the real AR of the image, and the nearest ratios with x16 dimensions.
4 - set in my script with all the other stuff the same cropping of Aspect and the dimensions I want choosen between the suggested ones.
5 - encode with square pixel.

Sorry for all this "pointing" but I've been using this method for a lot of time and I've always seen correct pictures imho, so I'm really not able to get the point..
If I'm wrong in something, just teach me. :)

[SeeMoreDigital]

5 - encode with square pixel.

Sorry for all this "pointing" but I've been using this method for a lot of time and I've always seen correct pictures imho, so I'm really not able to get the point..
If I'm wrong in something, just teach me. :)If you're generating encodes with square pixels and not adding aspect ratio signalling to distort the shape (ratio) of those pixels, then no you will "not able to get the point..."


Cheers

[SeeMoreDigital]

I know that is really not right, but, as I say, burning it on a dvd, it'll display correct on my TV .. :confused: What make and model of stand-alone player are you using to connect to your 16:9 TV?

[berrinam]

The figure I read for errors in AR is around 4%, meaning that most people won't notice an aspect error of less than 4% during playback.

Obviously, it is more obvious if you are going to look at screenshots, but what is the point of doing those tests if you can't notice it in playback? Furthermore, seeing whether the AR looks 'right' should be done as an absolute thing, because most people will only watch one copy of a film at a time. IMO, finding the 'right' solution even if you can only tell it by examining screenshots is the super-purist option and doesn't make sense to me from a practical viewpoint.

It actually turns out that a 4% error is quite large, so there is a lot of tolerance in these calculations.

For example:
1. Giving PAR of 2.35:1. On playback I get 1016x432 (using MPlayer)
2. Giving PAL (16:9). On playback I get 1048x432.
3. Calculating 720 x 432 by MAR (2.35:1) using ARS (141:100). On playback I get 1016x432.
Let's find the difference between the two extremes: 1016x432 and 1084x432:

1048 1016 1048
---- / ---- = ---- = 1.031
432 432 1016

So, even in this seemingly large range, there is only a variation of 3%. I'm not convinced that anyone could tell a difference during playback, so why does it matter?

Should I not just be using the DAR GKnot gives? So 720 x 432 by 2.37:1 (155:109) or something?Why not just test it out with what GKnot suggests, and if it looks wrong to you, look for a better solution, but if you don't notice anything, leave it alone.

[mod]

If you're generating encodes with square pixels and not adding aspect ratio signalling to distort the shape (ratio) of those pixels, then no you will "not able to get the point..."
Thanks for the reply :)
Ok, so the only difference between my method and the "correct" one is that:

- the pixel aspect ratio mustn't be square (according to tv)
or
- i have to add ars (to correct shaping)

In both cases, I have to introduce the correct AR settings in the XviD control panel, and here comes in the "point"?

PS: Then why I see correct images? [ Waitec HTX standalone ]. How can I check with PC if the final TV image will be correct? Is for the really little error committed? Because if I resize to x16 multiples, there's a range of ARs that will fall in the same final dimensions.

[SeeMoreDigital]

Hi Mod,

These are all questions that have been asked and answered before in other forum threads.

If you are not sure of the basics of anamorphic signalling and what it does and what it's used for, I would respecfully ask you search the forum.


Cheers

[mod]

Roger, and thanks for reply :)

[Audionut]

The are some movies, that when you crop away the black matte, in order to keep a mod 16 resolution, the resulting aspect ratio will be incorrect.

This tool will help alot.

Thanks very much SMD.
Sh*t hot.

[jv_guano]

What make and model of stand-alone player are you using to connect to your 16:9 TV?

I use both a Ndvx 2501 by Nortek (http://www.nortekonline.com/ENG/Product/product.asp?name=NDVX+2501&c=DVD&f=DVD%20PLAYER&po=False) and a DVD 612 by Philips (http://www.p4c.philips.com/cgi-bin/dcbint/cpindex.pl?sct=DVD_PLAYERS_SU&cat=DVD_PLAYERS_RECORDERS_CA&grp=HOME_AUDIO_VIDEO_GR&session=20060307072309_151.38.74.176&ctn=DVD612/021&slg=AEN&scy=IT) connected to a Panasonic TX-w28d3f 16:9 tv

but really, the important thing is that I see my movie correctly! You've been just too much kind so far! :)

[SeeMoreDigital]

Sadly I don't seem to be able to find out what type of chip-set is fitted into your Nortek NDVX 2501 MPEG-4 capable player.... :(

[jv_guano]

Sadly I don't seem to be able to find out what type of chip-set is fitted into your Nortek NDVX 2501 MPEG-4 capable player.... :(

can I do it in some way, like watching on my manual?

[SeeMoreDigital]

What happens when you play these MPEG-4_AR_Signalling_Test_Files (http://www.one.seemoredigital.net/MPEG-4_Player_Test_Files/MPEG-4_AR_Signalling_Test_Files.7z)?


Cheers

[mod]

@SeeMoreDigital: can you report please the algorithm used to calculate the PAR in your tool? I use:

|MAR-AR|*100 // num
--------------
MAR*|eAR| // den

where: MAR:movie aspect ratio (calculated after cropping)
AR:aspect ratio with current mod(16/8/4/2) setting
eAR:%error between AR and MAR

When I round it to integers I get different values (the % difference is really little btw).
To find the final integers I multiplicate num and den for their 1/decimal part (ie: 0.2012 -> 2012), find the MCD and divide num and den for that.

[SeeMoreDigital]

@SeeMoreDigital: can you report please the algorithm used to calculate the PAR in your tool?Hi Mod,

It's the same code as used with MPEG4 Modifier. So I guess you'll have to ask Moitah ;)


Cheers

[mod]

I took a look at the source, works perfectly now.
Useful as always, thanks :)

[delacroixp]

It's easier to correct the aspect ratio of an MPEG-4 source if it has no mattes. But it depends on how you've encoded it.

After reading some of the e-mails and PM's I've received it's become quite clear, some of you have generated some very peculiar shaped encodes....

Indeed, when generating "cropped and resized" encodes, some of you have elected to keep tiny bits of the black mattes in..... very strange!

The practice of encoding anamorphic movies has a certain beguiling sense of economic profitabillity... 415k pixels encoded IN and 590k pixels played-back OUT (PAL 16:9)... It would certainly seam like a 30% bonus...

I recently encoded The Deer Hunter (http://en.wikipedia.org/wiki/The_Deer_Hunter) (720 x 576 - PAL / 16:9). http://souls-online.net/delacroixp/AutoMKV/vlcsnap_TheDeerHunter_Thumb.jpg (http://souls-online.net/delacroixp/AutoMKV/vlcsnap_TheDeerHunter.jpg)

I ran it through Dr DivX which reported blackspace => L = 9 R = 8, T = 70 B = 71. To comply with mod 16, I...
under-cropped L = 8 [-1] & R = 8 [0] and
over-cropped T = 72 [+2] & B = 72 [+1] ...

Which left 704 x 432... a rather pretty number... which, when fed into the ARS calculator... set on custom 2.29:1 since (997/435 = 2.29)(original non-matte frame, before crop)... gave a result of 215:153... which seams to equate to a width of 989.28... a far cry from my original calc of 1004x432...


:):D:eek:
Pascal

[SealTooGreat]

Is there any tool for PAR->DAR calculation?
I need it cause "Nero Digital AVC export" in Adobe Premiere Pro 2.0, have only DAR option box, and I want to encode anamorphically, (input file is PAR=64:45).
Someone will say "Why don't you use Nero Recode?" -> simple GUI doesn't have ability for PAR/DAR signaling.(and funny DirectShow Nero AVC encoder has , viewing from GraphEdit http://www.invision.smileyville.net/smilies/conf (2).gif)

[bond]

there is no DAR in avc, therefore i think the tool is automatically recalculating your DAR to a proper PAR!?

[SealTooGreat]

^Yes, you are right^
but my input in premiere pro is 704x432(PAR=64:45) and I don't know what DAR's values to set in Nero AVC exporter?
Does someone know any tool for PAR->DAR?

[SeeMoreDigital]

DAR, PAR, SAR... At the end of the day they're all different terminologies that end up providing an Aspect Ratio Signalling (ARS) value.

EDIT: These days, it's possible to enter any ARS value you like into a decent MPEG-4 (Part-2/Part-10) encoding application. And have the resulting encodes displayed at any pixel shape you desire upon playback.

[SealTooGreat]

These days, you can enter just about any ARS value you like into most decent MPEG-4 Part-2 and Part-10 encoding applications. To alter the shape of the displayed pixels (and image) upon playback.
Do you know any tool only for PAR->DAR calculation - similar to ARS Calculator but with inverse function ?

[SeeMoreDigital]

Do you know any tool only for PAR->DAR calculation - similar to ARS Calculator but with inverse function ?What is it you are trying to do?

Can you provide more information about your source image. Such as a still frame?


Cheers

[SealTooGreat]

I need it cause "Nero Digital AVC export" in Adobe Premiere Pro 2.0, have only DAR option box, and I want to encode anamorphically, (input file is PAR=64:45).


but my input in premiere pro is 704x432(PAR=64:45) and I don't know what DAR's values to set in Nero AVC exporter?

I've already said. And I'm using AVS script for importing.
ARS Calculator gives DAR->PAR, I need opposite calculation (PAR->DAR).

[SeeMoreDigital]

I've already said. And I'm using AVS script for importing.
ARS Calculator gives DAR->PAR, I need opposite calculation (PAR->DAR).And as I've said: -

"DAR, PAR, SAR... At the end of the day they're all different terminologies that end up providing an Aspect Ratio Signalling (ARS) value"

[SealTooGreat]

Sorry SMD, this doesn't help me at all. I've said simple question, why I couldn't get simple answer.
edit:
Source: PAL DVD 720x576 (PAR=64:45) anamorphic
Crop: 704x432 (via AVS script and this is still PAR=64:45, regardless of cropping )
Resize: NONE
wishes: want to encode anamorphically.
problem: encoder accept only DAR numbers(x:y). How to determinate?... if possible can someone suggest PAR->DAR calculator app?
I would easily do that if I didn't crop 16px from width => DAR=1024:432=64:27

http://img530.imageshack.us/img530/1097/5thgg1.th.jpg (http://img530.imageshack.us/my.php?image=5thgg1.jpg)

[SeeMoreDigital]

I could not give you a simple answer because you did not provided enough information...

Looking at the image you provided, it seems as though the movies aspect ratio (MAR) is around 2.35:1.

So after feeding all the required information into the ARS calculator. Like this: -

http://img510.imageshack.us/img510/3007/arscalcgu4.png

You need to add an ARS (PAR, DAR, SAR) value of 199:138 to your 704x432 MPEG-4 video stream.


Cheers

[SealTooGreat]

I've encoded small sample, putting values 199:138 in DAR boxes of Nero AVC exporter (in premiere pro 2.0).
Snapshot by MPC
http://img201.imageshack.us/img201/677/5thdarik4.th.jpg (http://img201.imageshack.us/my.php?image=5thdarik4.jpg)
MPC's Properties:
http://img92.imageshack.us/img92/2750/propertiesqx8.th.jpg (http://img92.imageshack.us/my.php?image=propertiesqx8.jpg)
And this is how DAR boxes, in Nero AVC exporter, look:
http://img295.imageshack.us/img295/2388/neroavcparargi7.th.jpg (http://img295.imageshack.us/my.php?image=neroavcparargi7.jpg)
Testing several encodes I've concluded that Aspect ratio option is in fact DAR.

SDM, in ARS Calculation Tool, ARS=PAR and MAR=DAR (You can call it whatever you like.). So I've used PAR(ARS) values for DAR(MAR) as you suggested and output AR is wrong.
This is PAL DVD with cropped picture, so PAR is already 64:45(or ASR if you prefer ). So workflow, in this tool, should be like this: type resolution: 704x432, put 64:45 in ASR box and than calculate MAR(or DAR) - but this tool can't do that.

One request, if you are the author of this tool, could you add ability to calculate MAR(DAR) upon ARS(PAR) and resolution input. MPEG4modifier has this inverse function, but is limitted on ASP and AVI.

[delacroixp]

I'm trying to compare snapshots from HD and 720_anamorphic material...

If I use MKV signalling set to 1280x576... VLC plays correctly and makes a 1280x576 snapshot...
However, if I signal 1280x720 DAResolution it reverts to 1024x576 and I don't get get an HD-upscaled frame-snapshot...
I could simply upscale with Photoshop but it's less than ideal...

Ideally, I would be able to export an upscaled VOB or MKV frame, based on a frame number...

Any ideas...


:):D:eek:
Pascal

[SeeMoreDigital]

Hmmm.....

Provided you've cropped away all black mattes and are left with an image having a Pixel Frame Size (PFS) of 704x432. I can assure you that when you add 199:138 ARS to your MPEG-4 stream, the video image will be displayed at an MAR of 2.35:1

Indeed, here's what MP4Box reports: -

http://img241.imageshack.us/img241/5183/infose4.png

As you can see the "Indicated Track Size" is 1015x432 pixels. And 1015 divided by 432 equals 2.35:1


EDIT: And here's are some MPEG-4 samples using your original 704x432 image as the source: -

[pdanpdan]

I use this simple xls calculator. This value is used in mkv as aspect ratio, with square pixels encoded mp4

[SealTooGreat]

SMD, you are giving me PAR=199:138, but I need DAR values. I already have PAR which is defined by PAL source and it's 64:45, regardless of cropping.
Nero AVC exporter only accept integer DAR's values between 1-255, not decimal number, so I can not achieve accurate output playback resizing. So I encoded using res. 704x432 with Aspect ratio=44:27 ( I couldn't set Aspect ratio=704:432 cause of mentioned limitation, but dividing both values by 16 I've gotten same DAR(=44:27) proportion ). And than , using mp4box's cmd
MP4Box.exe -par 1=64:45 "5th_test.mp4"
.. resulting frame look:
http://img293.imageshack.us/img293/5329/5thcorrectparlg4.th.jpg (http://img293.imageshack.us/my.php?image=5thcorrectparlg4.jpg)

Main difference between your and mine steps is that your define new PAR (199:138) values when one already is known (PAR=64:45 is defined by PAL source). And there's a step when you are guessing:

Looking at the image you provided, it seems as though the movies aspect ratio (MAR) is around 2.35:1.
Loosing accurate DAR(MAR) is more visible if I do (on purpose ) strong overcrop on source image...so seeming/guessing DAR/MAR in (ARS) Calculation Tool is wrong step in process because:

strong overcrop on source(720x576) image, result(564x432) looks:
http://img166.imageshack.us/img166/4268/5th564x432overcropqy9.th.jpg (http://img166.imageshack.us/my.php?image=5th564x432overcropqy9.jpg)
ARS calculator gives ARS=9:5 using guessed MAR=2.35:1 and res.564x432:
http://img209.imageshack.us/img209/6083/arscalcjt7.th.jpg (http://img209.imageshack.us/my.php?image=arscalcjt7.jpg)
Applying ARS=9:5 on overcropped res.546x432 gives:
http://img181.imageshack.us/img181/9307/5th564x432overcroppar95mc5.th.jpg (http://img181.imageshack.us/my.php?image=5th564x432overcroppar95mc5.jpg)
Applying known PAR=64:45 on overcropped res.546x432 gives:
http://img167.imageshack.us/img167/1143/5th564x432overcroppar64tu6.th.jpg (http://img167.imageshack.us/my.php?image=5th564x432overcroppar64tu6.jpg)
And here's accurate DAR=1.857:1 using input res.564x432 and input PAR=64:45
http://img209.imageshack.us/img209/6991/arscalcrightdarpx2.th.jpg (http://img209.imageshack.us/my.php?image=arscalcrightdarpx2.jpg)
And that's what I have needed in the first place - to calculate accurate DAR. And tool which can do that - ARS Calculation Tool
isn't capable for PAR->DAR calculation(or ASR->MAR if you prefer using those names).

With PAR->DAR calculator , knowing input PAR and input resolution, I can achieve more accurate DAR (or MAR by your dictionary) - but only tool I can find is MPEG4modifier (limitted on ASP and AVI) which doesn't allow you calculating unless you load the file. I've re-encoded smal 264/mp4 sample to xvid/avi in order to use MPEG4modifier and to calculate more accurate DAR by known values(res=704x432 and PAR=64:45).
http://img81.imageshack.us/img81/4249/mpegmodifierii7.th.jpg (http://img81.imageshack.us/my.php?image=mpegmodifierii7.jpg)
So MAR=2.35:1 is wrong at very beginning, right value is MAR=2.318:1, and why the heck do you call it MAR when it already has the name - DAR? And ASR=SAR=PAR... Can we talk, using usual names for those signalings???!!!
It's a pity that those decimate DAR numbers(2.318:1) can't be used by Nero AVC exporter in premiere pro 2.0

[shon3i]

Just divide 1024 with 432 wich is 2.37 wich is correct DAR for you cropped resolution.

[SealTooGreat]

Just divide 1024 with 432 wich is 2.37 wich is correct DAR for you cropped resolution.

This would be correct if my cropped input is 720x432, but this is not the case cause I'm having 704x432. It's a PAL source so PAR is already 64:45.
MPEG4modifier (with res.704x432 input and PAR=64:45 set) gives DAR=2.318:1 which is in fact the most accurate value. Only problem is that Nero AVC exporter doesn't support decimate numbers. Anyway, I've found workaround using mp4box after finished encode.

[pdanpdan]

The most accurate would be 2,317695473 :)
The formula is simple:
InitialAspectRation(16/9 or 4/3)*Orig_Y/Orig_X*Cropped(final)_X/Cropped(final)_Y

It's allways working if the original source is well done.

[smok3]

why not just

DAR * height = PAR * width

so

DAR = PAR * width / height

= 2.3176954732510291

?

my python procedure;
>>> par=64.0/45.0
>>> par
1.4222222222222223
>>> x=704.0
>>> y=432.0
>>> par*x
1001.2444444444445
>>> _/y
2.3176954732510291