1:66.1 Letterbox --> Anamorphic

[simple_simon]

I want to use DVDRebuilder to convert a 1:66.1 ratio letterboxed in a 4:3 container. The convert feature in DVDRebuilder cuts too much off for this aspect ratio (60 pixels from the top and bottom). I need to cut 44 off the bottom and 46 off the top but then I can't figure out how much padding to add to the sides. I've googled myself silly and found so many conflicting things that now I'm as clueless as when I started.

To make things worse I've tested several anamorphic commercial releases and they all use various different pillar sizes. It seems that even Criterion (who I trust knows what they are doing) can't seem to be consistent regarding this, using different pillar sizes with different releases. The three most common I've found are 22, 24 & 30 pixels on each side. If all these movies have the same aspect ratio it seems that the space on the sides would be the same, otherwise I don't see how the aspect ratio could be the same. All the movies I included in this comparison have no space on the top or bottom so different sized borders on the sides would have to indicate a different aspect ratio although they all claim to be 1:66.1.

I did run across one tool that seemed promising, FitCD, until I began to play around with it. It seemed to want me to either use 24 pixels on each side or 32 depending on whether or not I had the ITU option clicked or not. I'm not sure how to tell what the ITU box should be set to but 32 pixels isn't even an example that I've found on commercial DVDS so that looks suspicious for example one.

Then I used a DVD that I knew had an aspect of 2:40.1 and FitCD came back and told me that the aspect was 2.4309. So either FitCD is untrustworthy or maybe the aspect ratio for movies are just rough estimates. So if they are estimates I don't know what the formula is to get the best rough estimate rather than trying to get an exact aspect which the major studios don't even try to do apparently. But that's all depending on the idea that FitCD is right which I'm not too sure about.

Also if FitCD is accurate it seems to shatter my illusions that I can cut the same number of pixels all the way around my picture and maintain my aspect ratio. I've always figured that if you stretch a picture a certain amount on the x axis then all you have to do you stretch it by the same amount on the y axis to maintain aspect but according to FitCD that's not true which doesn't make sense to me.

Anyway there has got to be an easier way to figure this out. Some formula or something that will tell me if I cut X off of the top and X off of the bottom then I need to add Y to each side to maintain an aspect ratio of 1:66.1.

Does anybody know what I'm talking about or know how to do this?

[Inspector.Gadget]

Post an unprocessed source sample, cut from the title you wish to remake. You can cut a VOB with DGSplit or cut and demux video only (preferable) with preview with DGIndex. Given that the encoded dimensions never change, a very short sample will suffice unless the actual matting of the movie in the encoded frame changes.

[simple_simon]

Okay, I can't do that now but I'll try to at some point. The movie is Inherit The Wind, if that helps at all. Although I have at least 5 others with the same aspect ratio that I want to do as soon I figure out what the formula & process.

[jdobbs]

What is the resolution (width x height) of the original? Is it anamorphic or 1:1 (I would guess the latter)? I'd also need to know whether you are NTSC or PAL (the conversion is different) because they each have different output aspect ratios.

You can't just say you need to "cut x off the top and y off the bottom" -- because that ignores the size of the output.

Is the source a DVD? If so, is it 4:3 or 16:9?

[MilesAhead]

The easiest way I've found to get a 16x9 video from a letterboxed 4x3 that's not very close to 1.85:1(iow, the DVDRB automatic mode won't work with it) is to put it through AutoGK at very high quality. In most cases AutoGK will autocrop it and you'll get a nice 16x9 .avi file. Especially if you don't have subtitles to worry about this is a nice option. You can either play it as is on your stand-alone .divx player, or if you must have DVD format, use it as input to a DVD converter.

I have some old Hong Kong DVDs that are letterbox 4x3 and the output from AutoGK actually looks better than the original on my Philips .divx player because I can put the TV in 16x9 mode. I just do one pass at about 92% quality. But if you're a stickler for quality use 2 pass mode.

[Inspector.Gadget]

Miles Ahead, that's suboptimal for DVD output. No sense in re-encoding twice; all you're doing in AutoGK is cropping and resizing and adding borders in Avisynth.

[MilesAhead]

Miles Ahead, that's suboptimal for DVD output. No sense in re-encoding twice; all you're doing in AutoGK is cropping and resizing and adding borders in Avisynth.

I don't reencode twice. I play the .avi file.
Sub optimal is better than no optimal.

Also I suspect more than that is going on since the .avi plays in 16x9 mode with correct aspect ratio.

[Inspector.Gadget]

I don't reencode twice. I play the .avi file.

That's fine, I was pointing out that "us[ing] it as input to a DVD converter" will result in suboptimal visual quality (and cost additional time to boot).

[Video Dude]

I want to use DVDRebuilder to convert a 1:66.1 ratio letterboxed in a 4:3 container. The convert feature in DVDRebuilder cuts too much off for this aspect ratio (60 pixels from the top and bottom). I need to cut 44 off the bottom and 46 off the top but then I can't figure out how much padding to add to the sides. I've googled myself silly and found so many conflicting things that now I'm as clueless as when I started.


There was a thread on VideoHelp that gave both the manual calculation and the FitCD way. I can't remember what it was or where the link is, but I still have the script:


Crop(0,48,-2,-48)
Spline36Resize(656,480)
AddBorders(32,0,32,0)


This will overcrop your example by 6 pixels, but it should be insignificant.

[MilesAhead]

This one?

http://forum.videohelp.com/threads/237369-xvid-to-DVD-resolution-and-aspect-ratio-woes

[MilesAhead]

Another quick and dirty way is use AviDemux 2.4 to autocrop. If you use v. 2.5 then I suggest 2 pass mode since the last good 1 pass for xvid on AviDemux is 2.4.

The AutoGK method won't work on everything, but I have quite a few 4x3 letterboxed DVD that it correctly converted to 16x9 .avi. It says some stuff about multi-mode or multi-phase or picking up more than one type of video, in the log during analysis. Then it spits out a nice 16x9 .avi.

[Inspector.Gadget]

Another quick and dirty way is use AviDemux 2.4 to autocrop. If you use v. 2.5 then I suggest 2 pass mode since the last good 1 pass for xvid on AviDemux is 2.4.

Have you filed a bug report or other documentation of this vague problem? Given the frequency of updates to Win32 Avidemux builds linked from these forums, I'm skeptical of any statement that broad being accurate.

Edit: OP, if using Avidemux, make sure to pay attention to setting the correct pixel aspect ratio in the Xvid config window and take PAR into account when resizing. Also, do any IVTC or deinterlacing BEFORE resizing.

[simple_simon]

Post an unprocessed source sample, cut from the title you wish to remake. You can cut a VOB with DGSplit or cut and demux video only (preferable) with preview with DGIndex. Given that the encoded dimensions never change, a very short sample will suffice unless the actual matting of the movie in the encoded frame changes.

ok here is the upload http://www.2shared.com/file/jdf6-jHF/INHERITdemuxed.html

What is the resolution (width x height) of the original? Is it anamorphic or 1:1 (I would guess the latter)? I'd also need to know whether you are NTSC or PAL (the conversion is different) because they each have different output aspect ratios.

Is the source a DVD? If so, is it 4:3 or 16:9?

I'm not sure what you mean by resolution of the original. It is, of course, standard dvd resolution untouched, 720x480. If I crop all the black bars off around all four sides then the actual picture resolution is 640x390.

DVD Source
Non-Anamorphic
NTSC
4:3
1:66.1 Intended Aspect Ratio

You can't just say you need to "cut x off the top and y off the bottom" -- because that ignores the size of the output.

I'm not sure what you mean by this. I want the output to be regulation dvd resolution, 720x480, but with an aspect ratio of 1:66.1.

I basically want to do what DVDRebuilder does when you use the convert to 16:9 option but alter the avisynth script afterwards with the correct crop and addborders values to give me a 1:66.1 aspect ratio.

There was a thread on VideoHelp that gave both the manual calculation and the FitCD way. I can't remember what it was or where the link is, but I still have the script:


Crop(0,48,-2,-48)
Spline36Resize(656,480)
AddBorders(32,0,32,0)


This will overcrop your example by 6 pixels, but it should be insignificant.

I shouldn't have to overcrop the height at all. Why couldn't i just crop by 6 pixels less than your example and just adjust the addborders values accordingly.

Also like I said before, out of the 10+ movies I've looked at so far that were already in anamorphic 1:66.1, none of them used 32 pixel borders so I just don't see how FitCD is coming up with that value.

[Inspector.Gadget]

Try this:

crop(0,46,0,-44)
Spline64Resize(672,480)
AddBorders(24,0,24,0)
# Spline64Resize(854,480) take this line out of your encoding script altogether, but you can uncomment it to preview the actual dimensions

I went non-ITU, but adaptation to ITU isn't difficult. Content AR is 1.66.....:1. Feed it to an encoder with the PAR @ the NTSC 16:9 value and it should look good.

[manono]

Those are pretty much the figures I get as well, but with ITU resizing turned on in FitCD (as it should be, I believe).

simple_simon, FitCD is accurate, if you set it up correctly. You can use Inspector Gadget's script in DVD-RB's filter editor to make the 16:9 DVD at the correct 1.66:1 ratio.

[simple_simon]

Well the problem with that is I don't know when to us ITU. But I went under the assumption that FitCD knows whether or not to tick that box when the source video is loaded hopefully. Anyway this is what I ended up using.

LanczosResize(656,480,1,44,718,394)
AddBorders(32,0,32,0)

Now the 32 pixels value for the borders was bothering me because like I said no other commercial 1:66.1 movie that I've found has that size borders. But from what I've been reading I think it might make sense now. It seems like when a widescreen film is converted to 4:3 dvd format, 8 pixels have to be cropped off of both sides in order to fit that format in the correct aspect ratio. So when we take that as our source to convert back to anamorphic widescreen, those 16 pixels have to be added back in to compensate for the ones originally taken away.
So I think that really the borders are 24 pixels plus 8 pixels to replace the 8 pixels of actual picture cropped by the dvd manufacturer would equal 32 pixels.
I still don't fully understand all of this aspect ratio stuff completely and probably never will but I think this is right from what I've been reading. If anybody who knows better knows different please let me know.

[manono]

It seems like when a widescreen film is converted to 4:3 dvd format...
What 4:3 DVD format? Are you talking about the 720x480 resolution of NTSC DVDs? If so, it's 3:2.
...8 pixels have to be cropped off of both sides in order to fit that format in the correct aspect ratio.
That was already taken into account in both Inspector.Gadget's and my calculations. Are you saying now you want to make a 704x480 DVD (perfectly legal)?
If anybody who knows better knows different please let me know.
Inspector.Gadget already gave you the correct script and I agreed with him.

[simple_simon]

What 4:3 DVD format? Are you talking about the 720x480 resolution of NTSC DVDs? If so, it's 3:2.

As far as I'm aware, DVD only has two aspect ratios, 4:3 and 16:9. I don't know where you're getting 3:2. The only time I've seen that figure is when talking about 3:2 pulldown which is something completely different. And yes, like I've already said, it's a NTSC DVD.

That was already taken into account in both Inspector.Gadget's and my calculations. Are you saying now you want to make a 704x480 DVD (perfectly legal)?

This you took completely out of context and apparently didn't read the original paragraph yourself. I was referring to the fact that the original DVD manufacturer originally cropped 8 pixels off of each side which is apparently necessary in order to convert to 4:3 Letterboxed aspect ratio. I'm not cropping those 8 pixels. They've already been cropped. I'm adding them back in in the form of extra border width to compensate for them. Hence the 32 pixel borders instead of 24 which would be what the DVD would have had if it had been made anamorphic widescreen from the start.

Inspector.Gadget already gave you the correct script and I agreed with him.

You didn't agree with him because he didn't use ITU in his example and you did and your version wasn't even 1:66.1.

But anyway I was asking for clarification about whether it's true or not about those 16 pixels being cropped originally to convert the film to 4:3 NTSC DVD aspect ratio.

I went non-ITU, but adaptation to ITU isn't difficult.

Inspecter.Gadget, what do you mean by this? What is the adaptation procedure to ITU and how do I know when I need to do this?

I've read on another board that the pay version of FitCD scans your source and tells you whether it is ITU compliant or not but they also say you can do it manually by counting the number of pixels in the original picture once all borders are cropped but they never go into detail about what the calculation actually is to figure that out after that.

[Inspector.Gadget]

No software can tell you whether a DVD was created according to ITU sizing procedures. That's nonsense. You'd have to have the film master in front of you to compare to the encoded result.

[manono]

As far as I'm aware, DVD only has two aspect ratios, 4:3 and 16:9. I don't know where you're getting 3:2. The only time I've seen that figure is when talking about 3:2 pulldown which is something completely different. And yes, like I've already said, it's a NTSC DVD.
You're right, I misunderstood you. But since what you said made no sense at all (I was referring to the fact that the original DVD manufacturer originally cropped 8 pixels off of each side which is apparently necessary in order to convert to 4:3 Letterboxed aspect ratio.), the misunderstanding is justified, I think. I was referring to the native 3:2 NTSC resolution. 720/480=3:2. If done correctly nothing is cropped from the sides. Rather, it's put on the DVD (both 16:9 and 4:3 DVDs) in a 704 width with 8 more columns of pixels added to the left and right to fill out the 720 width. This isn't done all the time, of course.
Hence the 32 pixel borders instead of 24 which would be what the DVD would have had if it had been made anamorphic widescreen from the start.
Do it anyway you like. However you asked for the proper script to do this and Inspector.Gadget already gave it to you.
You didn't agree with him because he didn't use ITU in his example and you did and your version wasn't even 1:66.1.
We arrived at the same conclusion using different methods. And mine was 1.66:1. I have no idea what makes you say otherwise. The 720x390 resolution I entered in the box is what remains after the cropping is done on your 4:3 DVD.
But anyway I was asking for clarification about whether it's true or not about those 16 pixels being cropped originally to convert the film to 4:3 NTSC DVD aspect ratio.
I doubt it, but as he says there's no real way to know. It's certainly not necessary.

[simple_simon]

No software can tell you whether a DVD was created according to ITU sizing procedures. That's nonsense. You'd have to have the film master in front of you to compare to the encoded result.

Well I don't own Fit2Disc. I was going by what I read on this page http://forum.videohelp.com/threads/145529-Should-ITU-R-BT-601-4-in-FitCD-be-turned-on-when-resizing

If done correctly nothing is cropped from the sides. Rather, it's put on the DVD (both 16:9 and 4:3 DVDs) in a 704 width with 8 more columns of pixels added to the left and right to fill out the 720 width. This isn't done all the time, of course.

Here is one of the sources that I read that made me believe that when a widescreen source is converted to 4:3 that 8 pixels have to be cropped off the left and right to make it work. http://www.animemusicvideos.org/guides/avtech/aspectratios.html#mozTocId829564
But i guess you're saying that 8 pixels are actually added to each side. Why is that? Why wouldn't it just be scaled to 720 to begin with?

We arrived at the same conclusion using different methods. And mine was 1.66:1. I have no idea what makes you say otherwise. The 720x390 resolution I entered in the box is what remains after the cropping is done on your 4:3 DVD.

Your example ends up with a 1.7016 aspect. Even though it is close, how is that the same as 1.66:1?

[MilesAhead]

That's why I say sometimes it's easier just to let AutoGK do it. It figures it all out. Slice a piece off the DVD and convert to .avi. See if the aspect ratio comes out right after the autocropping etc.. If so, do the whole vid. ;)

[manono]

But i guess you're saying that 8 pixels are actually added to each side. Why is that? Why wouldn't it just be scaled to 720 to begin with?
8 pixels added? No, I'm saying the calculations can be properly done whether the active video is 704 pixels wide or 720 pixels wide. But, the 4:3 and 16:9 are based on a 704 width. Which is why the aspect ratio increases a bit when dealing with a full 720 width.
Here is one of the sources that I read that made me believe that when a widescreen source is converted to 4:3 that 8 pixels have to be cropped off the left and right to make it work. http://www.animemusicvideos.org/guid...mozTocId829564
That's a good article. Too bad you don't understand what you read. So, when they say cropping 8 from the left and right allows a resize to a 640x480 square pixel video, the inference is that if the active video is the full 720 width and can't/shouldn't be cropped, it's not really a 1.33:1 video, and something like 656x480 (1.367:1) would be accurate. Again, true 4:3 and 16:9 resizes are based on a 704 width. If the DVD contains a full 720x480 pixels, it's wider than 1.33:1 (4:3 source DVD) or 1.78:1 (16:9 source DVD).

[simple_simon]

Again, true 4:3 and 16:9 resizes are based on a 704 width. If the DVD contains a full 720x480 pixels, it's wider than 1.33:1 (4:3 source DVD) or 1.78:1 (16:9 source DVD).

So is that why your resize example was for an aspect of 1.7016? Is that what the aspect ratio for 1.66:1 should be when dealing with 720 pixels instead of 704?

[manono]

Is that what the aspect ratio for 1.66:1 should be when dealing with 720 pixels instead of 704?
Yes, that's what I'm saying. Plus, there's some slight change of aspect ratio when cropping for Mod2 (as is necessary) and resizing for Mod16 (as is recommended). There's quite a lot of discussion about this here and there. Here's one very helpful post. It even has some support for your position, although I think here at DOOM9 there's not much argument:

http://forum.videohelp.com/threads/322346-same-resolution-but-difference-in-display-w-r-t-height-and-width?p=1995959&viewfull=1#post1995959

The figures are given for 704 widths. That's why when a 16:9 DVD fills the entire 720x480 frame, the real aspect ratio is about 1.82:1 (although that isn't always honored by the DVD production companies or by the players). And in the Newbies Forum there's a current discussion about the same thing:

http://forum.doom9.org/showthread.php?t=155240

If you really want to get into it, try and make your way through this:

http://www.iki.fi/znark/video/conversion/

[MilesAhead]

Have you filed a bug report or other documentation of this vague problem? Given the frequency of updates to Win32 Avidemux builds linked from these forums, I'm skeptical of any statement that broad being accurate.

Edit: OP, if using Avidemux, make sure to pay attention to setting the correct pixel aspect ratio in the Xvid config window and take PAR into account when resizing. Also, do any IVTC or deinterlacing BEFORE resizing.

You skepticism notwithstanding, I posted a screen shot when reporting the issue. The response was "use 2 pass." That's the extent of the update in this area. For some reason they don't want to use the high precision motion detection. I can't read their minds to figure it out. I just use version 2.4 that works well with one pass mode.

edit: anyway, back on topic. I tried enabling ITU with 16x9 on one run. The source letterboxing looks pretty close to 1.85:1 if the black bars were chopped so it's tough to say if that made the difference. I'll have to try on more sources. If I can just check that option then I'd use DVDRB instead.

edit2: I did another run with a letterboxed source that I would guess is 2.35:1 if cropped. The output aspect looks fine. I thought sure I tried the ITU option when I first attempted these but I may have missed a click or something. On my quad the video encoding was much faster than AutoGK to produce an .avi. Unless something changes this is my preferred method to "sixteen-by-nine-ify" stuff. :)

[MilesAhead]

Not to beat this thread to death, but I did find something interesting. When processing windowboxed dvd if I use DVD RB avs convert to 16x9 with ITU option checked, the resulting dvd has the image sized to fill the 16x9 frame on the TV. If I use AutoGK I'll get the postage stamp effect. In the first case the picture is softer since it has been sized up to fill the 16x9 TV display. In the second case the picture is sharper since the .avi frame is not sized up but shown in the postage stamp.

It gives you a choice without getting into doing your own calculations. You may want to slice off a piece of video and try it with both methods. Seems like the softening of the picture is only very noticeable with windowboxed dvds. Even 2.35:1 letterbox converted to 16x9 with the DVD-RB method the picture was still pretty crisp. Just something to mess around with. :)