Resize calculator PHP

[krosswindz]

Originally Posted by smok3

yes, but one can't really know if the theatrical DAR is really what was transfered to DVD (there could be some cropping in the process, ect) when on the other hand PAR is always known to the end user.

Very true, during the transfer if they cropped the picture then you would be loosing the theatrical DAR. It would be nice if there was some way of determining the DAR that DVD was authored in. Would be really helpful when you re-encode.

[smok3]

uhmm, yes, you crop the blacks, use the correct PAR and there you have your correct source DAR (unless the production company f*** up in conversion somehow, but you can't really be sure about that, unless you know the movie really really well...)

---

anyway, lets go the other way, for example i have done some renderings in my favorite 3d package, this are 2048x866 frames (35mm Full Screen Super 4k cineon - preset) with PAR 1:1, and for some reason i would like to do wide PAL dvd out of the animation;
http://somestuff.org/resizeCalc.php?...css=&doit=true
(i would crop some pixels in the bottom, so i get less error and there goes away my original DAR...)

[krosswindz]

Not only do you loose the original DAR, you also loose some part of the image. Wish things were so much easier with encoding. I think the only way one can really not have problems would be when creating the images based on what the final product would be.

[SeeMoreDigital]

Originally Posted by smok3

hmm, well, imho there is enough confusion allready about this 3 letter beasts, how about not inventing new ones?
(MAR actually stands for Modified aspect ratio)

As of December 2007!!!

I wonder who decided to place that new acronym on Wikipedia

[smok3]

oh, it wasn't me

I think the only way one can really not have problems would be when creating the images based on what the final product would be.

in this days it is quite usual that one must produce video for different aspect ratios/different media systems as well (well known example from tv world is 14:9, where you can shoot in 16:9 with 14:9 picture in mind or with 4:3 with 14:9 picture in mind..., cough), sometimes i do 4:3 version for TV and 16:9 version for web, ect.

(using loose conversation-purpose numbers here)

[krosswindz]

is the math for PAL <-> NTSC right. Because video frame height are different for both.

[smok3]

i think for D1 pal to D1 ntsc this should be simply good enough
http://somestuff.org/resizeCalc.php?...css=&doit=true (sampling matrix width in µs =53.33333 µs)
or maybe
http://somestuff.org/resizeCalc.php?...css=&doit=true (sampling matrix width in µs=52.14815 µs)
(makes sense that there is minimum DAR error, which needs not to be fixed, although as you may figure out the active area wont match perfectly in some cases, for this kind of conversions i would recommend a manual calc method which must start with collecting all the needed data - and you have to do it correctly just once anyway)

[krosswindz]

Quoting http://lipas.uwasa.fi/~f76998/video/conversion

If vertical_conversion_factor is anything other than 0.5, 1 or 2, you are probably trying to do a standards conversion between a 625/50 system and a 525/59.94 system. Standards conversion (when done right) is a highly demanding process and outside the scope of this document.

Here the vertical conversion factor would not be 1. Since the active picture heights vary. Would the resized image be fine?

[smok3]

i'am not sure what he meant with 'demanding' process? (maybe that one shouldn' do it at all...)

[krosswindz]

Originally Posted by smok3

i'am not sure what he meant with 'demanding' process? (maybe that one shouldn' do it at all...)

I am not sure how demanding the process is but I have seen a lot of Indian movie DVDs which are PAL to NTSC transfers and are such pain to deinterlace. Apart from being a bad transfer they all have bad aspect ratio too.

[krosswindz]

Is there any link for the math if the source is BluRay/HD DVD?

[smok3]

the hi-defs are mostly with square PAR i imagine (no i haven't seen the complete standard for either of this yet).

[krosswindz]

^ I assume that they should be square, havent found any mention of them of not being square AFAIK.

[SeeMoreDigital]

There are quite a lot of 1440x1080 sources knocking around, complete with 4:3 (PAR) aspect ratio signalling, creating a displayed shape of 1920x1080 pixels...

[smok3]

some numbers are here;
http://developer.apple.com/documenta...section_2.html
http://www.surrealroad.com/research/...a-resolutions/

DVCPRO HD (as i recall from hvx200) is either, using smaller res:
------------------------------------------------------
960x720 (square should be 1280x720), PAR is around 1.333 (so you can use hdv preset);
http://somestuff.org/resizeCalc.php?...css=&doit=true
or bigger res:
1280x1080 (square should be 1920x1080), PAR is around 1.5
http://somestuff.org/resizeCalc.php?...css=&doit=true
------------------------------------------------------
this needs to be confirmed (or denied).

p.s. hvx200 960x720 scaled to square 960x544 example (seems correct or very close):
http://somestuff.org/flashAVC/flvpla...e-x960y544.mp4

08d
.added some examples and links (no math changes)

[krosswindz]

I am not sure but I am kind of revisiting the problem we had talked earlier. Now this was something that I see personally.

The movie DVD has been marked in the packaging with "aspect ratio 2.40:1"

With the cropping resize calc displays the DAR as 2.49

http://somestuff.org/resizeCalc.php?...css=&doit=true

DVD has been authored by Sony, its probably one of the first sony dvd that I am backing up ever. My question would be why is there this difference?

[smok3]

various reasons:
1. sony is wrong
2. you are wrong by choosing wrong method somehow
3. my calc is wrong
did you try any alternative calc? or manual calc maybe?

[SeeMoreDigital]

Originally Posted by krosswindz

I am not sure but I am kind of revisiting the problem we had talked earlier. Now this was something that I see personally.

The movie DVD has been marked in the packaging with "aspect ratio 2.40:1"

With the cropping resize calc displays the DAR as 2.49

DVD has been authored by Sony, its probably one of the first sony dvd that I am backing up ever. My question would be why is there this difference?

Can you try this please: -

• Play the DVD in a software player
• Find a light scene where the black mattes are clearly visible.
• Take a snapshot
• Upload the snapshot to the forum

From the snapshot I should be able to tell you the movies aspect ratio...

[smok3]

08e
.internal release (last source code stays 08d), just some php fixes, lets see how it behaves before releasing the code.
08f
.added primitive unique visitors counter, some html fixes, sources are out

[krosswindz]

Originally Posted by smok3

various reasons:
1. sony is wrong
2. you are wrong by choosing wrong method somehow
3. my calc is wrong
did you try any alternative calc? or manual calc maybe?

I normally use one of the two calculators, one is yours the other one being http://www.animemusicvideos.org/guid...esizecalc.html both spit out similar values, the difference being how the ar error is calculated.

Originally Posted by SeeMoreDigital

Can you try this please: -

• Play the DVD in a software player
• Find a light scene where the black mattes are clearly visible.
• Take a snapshot
• Upload the snapshot to the forum

From the snapshot I should be able to tell you the movies aspect ratio...

Used vlc to grab these scenes, the movie is really dark so this is the best I could do. As you can see there is this white line on the top and bottom in many frames of this movie, I crop them off also along with the black border on the side before I back up.