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Old 6th June 2004, 19:46   #21  |  Link
bond
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Quote:
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Don't mean to add stones to burden, but would it be possible to add custom resolutions?
as moitah wrote, its already possible when using
par:<par_width>:<par_height> (Pixel Aspect Ratio)
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Old 6th June 2004, 19:51   #22  |  Link
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Quote:
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Don't mean to add stones to burden, but would it be possible to add custom resolutions?
(I'm currently wrangling '2001: A Space Odyssey', which has an AR of 2.21:1)
2.21:1 eh!

On an PAL DVD this gives you 464 vertical image pixels and 112 (2 x 56) matte pixels.

On an NTSC DVD this gives you 384 vertical image pixels and 96 (2 x 48) matte pixels.

Did you crop away the mattes or keep them in?

If you kept them in just use just use either setting 4(PAL) or 5(NTSC). But without knowing more details about how Moitah's tool works I can't help you any further!


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Old 6th June 2004, 20:11   #23  |  Link
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hell ya! brought new life to my old 352x480 divx encodes:

rp divx.avi divx2.avi dar:352:480:4:3

i use xvid now, but i think this tool is even more important for the divx folks. thanks.
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Old 6th June 2004, 20:18   #24  |  Link
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@bond ... Note to self: Pay more attention to posts with commands.


@SeeMoreDigital ... I just ripped it from the (PAL) DVD last night. My Vdubmod has died and refuses to be resuscitated. So to get the image size, I played it in windvd:

It's anamorphic 720x576,

1.78:1 with cutoff panels

And a quick glance in photoshop gave ~2.21:1 with the panels removed.

I.e. the image ~720x326

So encoding it with panels intact with a 16:9 flag should get the desired aspect ratio. But if I want to remove the panels?
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Old 6th June 2004, 21:01   #25  |  Link
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If its an anamorphic DVD just use Setting 4 - 16:9 PAL.
It should not matter if you crop away the black bars as it sets the Pixel Aspect Ratio.
At least it works for me this way.
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Old 6th June 2004, 21:15   #26  |  Link
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Of course!
Thanks!
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Old 6th June 2004, 21:18   #27  |  Link
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When you say panels, do you mean the black bars (ie: the mattes).

For a list of the most commonly used ratio's and how the image and matte pixels compare, check out my list.

For more info about what an 'anamorphic' image actually looks like on an PAL DVD look here.

Keep in mind you can't just capture DVD images and expect them to appear at the correct ratio via any photo imaging software. Although the height of the image will contain the correct quantity of pixels the width will not.... that's why they are called 'anamorphic'.


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Old 6th June 2004, 22:19   #28  |  Link
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Yes, I mean the mattes. I have a bad habit of calling the matte sheets you put on preview monitors 'panels'.

I have backed up anamorph DVD's with 16:9 flagged xvid before, but the films were always shot in 16:9. For some reason, it didn't cross my mind that the matte fields would be anamorphically warped too; I just looked at 2.21:1 and went "DUH".


The screencap in WinDVD produces correctly stretched (and in this case, upscaled to 1024x576 too) images.


Thanks all!
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Old 6th June 2004, 22:47   #29  |  Link
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Hi bot,

An anamorphic image can be a difficult concept to grasp at first. There are two different methods of putting an anamorphic image on a DVD. The first is 4:3 anamorphic and the second is 16:9 anamorphic.

This is what a 2.35:1 AR image looks like when it's stored on a PAL (720x576) 16:9 'wide-screed' DVD: -



As you can see it's all squashed up and it will remain this way until the appropriate player receives the 'anamorphic flagging signal' (buried in the video stream) to ping it out.


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Old 6th June 2004, 22:48   #30  |  Link
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Quote:
Moitah wrote
I noticed VLC pays attention to the aspect ratio even when in an AVI container.
Yes, non-directshow players such as VLC and mplayer are able to read the AR information from the MPEG-4 bitstream.
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Old 7th June 2004, 14:47   #31  |  Link
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[OT]
SeeMoreDigital... Yes, here's some more numbers (for the trivia inclined gits like me): 2001 was shot in both 70mm Super Panavision (and 70mm Todd AO for special effects sequences), giving it an original aspect ratio of approximately 2.20:1. Most theatres didn't have the curved super panavision screen (or designated projector) to show it that way, so they used a 35mm anamorph super panavision print, giving an aspect ratio of approximately 2.34:1. The DVD is scanned and transcoded from the restored Super Panavision 65mm (!) print (2.28:1), retaining the 2.20:1 aspect ratio of the original print with matte. Now, can anyone blame me for being confused about the 2.21:1 display of a 1.78:1 anamorph representation of a 2.20:1 or 2.34:1 or 2.28:1 film
[/OT]

Anyway, good news about the progress of the AR flag changing utility!!
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Last edited by bot; 7th June 2004 at 15:11.
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Old 7th June 2004, 15:50   #32  |  Link
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The way an anamorphic image is shot/placed on film has nothing to do with how it's telecined onto an DVD.

With regards to PAL (but the same goes for NTSC), there are many technical reasons why an 'anamorphic 16:9 frame' 720x576 was used and a 'true 16:9 frame' 1024x576 was not.

Sufficed to say in 1998/99 the Mpeg2 chip-sets may not have been up to the task, of crunching the additional 175,104 pixels required and the costs would certainly have been more. And don't forget DVB-T and S signals are anamorphic too!

Some time ago I talked about the quality benefits of re-encoding Mpeg2 720x576 'anamorphicly framed' images to Mpeg4 1024x576 'true 16:9 framed' images... many people on the forum could not see the point and thought it was a waste of time but some have changed their views.... It's one of those 'the hand is quicker than the eye' scenarios... but with pixels

Anyways, a movie at a cinema can in theory be presented using any aspect ratio, as a piece of film can be cropped and have mattes applied to form any AR size.

When you mentioned earlier that you had calculated the movies 2.21 AR to be 720x326 pixels, this intimated to me that you had not yet grasped the theory behind DVD anamorphics.

I hope you now understand that the 'horizontal' pixel axis is the anamorphic one. And the 'vertical' pixel axis is not - Regardless of weather mattes are used.


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Last edited by SeeMoreDigital; 7th June 2004 at 16:26.
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Old 7th June 2004, 15:59   #33  |  Link
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Quote:
Originally posted by SeeMoreDigital
When you mentioned earlier that you had calculated the movies 2.21 AR to be 720x326 pixels, this intimated to me that you had not yet grasped the theory behind DVD anamorphic. [/B]
Well, yes, I was referring to the (decoded and) 'decrunched' image. I knew the DVD was anamorphic. The original question came from my believing that just the 2.21:1 area of information (and not the excess matte area) had been squeezed into the anamorph frame: I thought I needed a 2.21:1 aspect ratio flag .

-And I agree with you on the benefits of transcoding anamorphically.
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Old 8th June 2004, 01:33   #34  |  Link
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I can't get this to work, well, let me rephrase that. I can change the flag, but no media players will display it correctly. I tried. windows media player 10, media player classic, realplayer 10, zoomplayer pro, nero showtime and winamp 5.

I have only tired using the xvid decoder, do I need to use a different decoder?
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Old 8th June 2004, 01:47   #35  |  Link
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SiXXGuNNZ,
the tool changes the information in the MPEG-4 bitstream, not in the AVI headers. No directshow-based decoder/player combination can read that information from an AVI container (anyone correct me if I'm wrong).

You could either try remuxing the video to MP4 as bond did, or use VLC, or mplayer (see my previous post for link).
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Old 8th June 2004, 02:26   #36  |  Link
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makes more sense then if it is a mp4 then, I read above that it changed the flag in the mp4 stream and not the avi, I did not realize it had to be an mp4 tho, I wish mp4's were a bit easier to make, I will try out mplayer, thanks
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Old 8th June 2004, 09:19   #37  |  Link
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Quote:
Originally posted by SiXXGuNNZ
I read above that it changed the flag in the mp4 stream and not the avi
this tool does not change the AR in MP4 nor in AVI
it changes the AR in the video bitstream itself
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Old 8th June 2004, 10:31   #38  |  Link
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SiXXGuNNZ,

Nero's ShowTime player can display anamorphic AVI's and MP4's correctly as long as you swap it's DSdec filter over to this version!


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Old 8th June 2004, 15:39   #39  |  Link
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OK, seeing as though I'm a total thicky when it comes to no GUI based tools. Can somebody here change the AR of this DivX 720x576 2.35:1 clip for me and post it please.


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Old 15th June 2004, 04:18   #40  |  Link
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Quote:
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SiXXGuNNZ,

Nero's ShowTime player can display anamorphic AVI's and MP4's correctly as long as you swap it's DSdec filter over to this version!


Cheers
I was wondering if you could get me that older filter again, I dunno where the copy I downloaded went

also, a gui is out for this app now

http://forum.doom9.org/showthread.php?s=&threadid=78050
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