General Resizing HEIGHT/Avisynth understanding

[Krelmaneck]

Hi people of videohelp.

I need some help with resizing as it relates to HEIGHT for NTSC. I have quite a bit of good help from the doom9 forum but they are probably shaking their heads now. So maybe some of you guys can help me understand.

As I understand so far, NTSC heights for a video generally do not change but as I have seen people's scripts I have seen more heights than just 480.

I also am no longer going by the active area as outlined in the Article "A quick Guide to Digital Video Resolution and Aspect Ratio Conversions.


What I have learned from Doom9 is that you take the width and multiply it by the reciprocal of the par. The PAR for DVD can be found by par=dar/sar 4/3 / 704/480 = .909090909090909 or 10/11. And if I am not mistaken but HAVE NOT CONFIRMED YET BY ANYONE the PAR for SVCD for 480 x 480 would be 4/3.


And the other thing I have learned is that if you have a outgoing source of 352 x 360 and you want to get the new height for DVD do this: take the height target (480) and divide by height source 360 and coincidentally you get: 4:3 in this example. Then you take that answer and multiply it by the source width and the RECIPROCAL of the target PAR that you figured out earlier. I heard professionals use this par.

4/3 * 352 * 11/10 (inversed)

Thus

LanzcosResize(516,480)
AddBorders(102,0,102,0)


So now you are CAUGHT UP NOW to where I have left off on the other forum.


I still have some questions now regarding to width.

Above is a perfect example of what to do.



But since we are talking about width would this be appropriate for DVD?

I forgot some information: if the two example below were 640 x 360 would the following bottom one's be acceptable? ADDED


LanzcosResize(704,360)
And then add borders to equal 720 x 480


or how about just NO BORDERS -- or will the encoder just spit this one out and say try again buddie? In other words, you said screw the height--it stays, thus 640 x 360 = 640/1 (11/10) =7,040/10 = 704
LanzcosResize(704,360)






Is 360 ACCEPTABLE as HEIGHT? And if so WHY is it acceptable? As from what I know most heights of NTSC stay at 480. This is a honest question that I am asking. Not a test. And not a troll. As I told you, people at doom told me alot of good things about width. I need to UNDERSTAND calculating HEIGHT.


And what is the difference between these bottom two scripts if you took a 352 x 360 source?

LanzcosResize(704,480)

and


LanzcosResize(516,480)
AddBorders(102,0,102,0)


And for OLD SCHOOLERS, if you took the 352 x 360 source wanting to turn it into a 4:3 SVCD that it not trendy anymore, besides 480 as a height(480 x 480), is there any other acceptable heights for SVCD? Can 360 work as a height? Why? it is not 480. Some people have told me not to even touch the height when resizing. Does 360 magically turn into 480 height somehow?

Again, this is NOT A TEST. This is so that I can have a more complete understanding of resizing. The doom9 people kind of got tired with me because it took like 15+ post for me to understand WIDTH. But now, I would like to complete the end of the conversation using this forum where people may have more fresh opinions.

[jagabo]

NTSC DVD requires 720x480, 704x480, 352x480, or 352x240 frame sizes. No other sizes are acceptable. If you come up with any other size it will have to be padded or cropped to match one of those sizes.

The DVD spec refers to the MPEG 2 spec regarding aspect ratios. The MPEG 2 spec does not follow the ITU spec. It says the aspect ratio refers to the full frame unless the optional sequence_display_extension is present (in which case the aspect ratio refers to the frame size indicated in the extension). This is at odds with the ITU 601 D1 spec which says the aspect ratio refers to center 704x480 sub section of a 720x480 frame. So on a DVD the 4:3 or 16:9 image is contained in the full 720x480 frame. You can avoid this discrepancy by using a 704x480 frame.

So the pixel aspect ratio on a 720x480 4:3 DVD is 8:9, not 10:11. For a 720x480 16:9 DVD it is 32:27, not 40:33. Otherwise the calculations are the same:

DAR = SAR * PAR

For example:

DAR = 720:480 * 8:9
DAR = 720/480 * 8/9
DAR = 720 * 8 / 480 / 9
DAR = 1.333... = 4:3

In the real world the difference between the MPEG2 spec and the ITU spec is often ignored. Some professionally mastered DVDs follow one, some the other. Some players follow one, some the other, some depend on which output you use. My Philips DVP 5992 follows the ITU spec at the s-video and composite outputs, but follows the MPEG 2 spec for upscaled HDMI output.

[Cornucopia]

I find more consistent results by looking at the center 704x480, using 10:11 (or 40:33) and then padding the extra 16pixels (whether with black or signal). Otherwise, I completely agree with jagabo.

The thing to remember is that in analog video, only the # of lines/rows is invoiable (fixed in stone). It's the width that one ought to be adjusting, so most of those calculations of yours were in the right vein, but taking the wrong approach.

Scott

[Krelmaneck]

I find more consistent results by looking at the center 704x480, using 10:11 (or 40:33) and then padding the extra 16pixels (whether with black or signal). Otherwise, I completely agree with jagabo.

The thing to remember is that in analog video, only the # of lines/rows is invoiable (fixed in stone). It's the width that one ought to be adjusting, so most of those calculations of yours were in the right vein, but taking the wrong approach.

Scott

The people at doom told me that (704 x 480) PADDED to meet 720 x 480 standards is something that the broadcasting industry uses for proffesional DVD's hence the 10:11 par that I should aim for but PAD it to meet 720 x 480. In other words, they told me to write the avisynth script to so that it is RESIZED to 704 x 480 AND padded so it meets the 720 x 480 standards.


My main concern, and here is an example, if you had a 352 x 360 SOURCE targeted for 720 x 480 (resized to 704 x 480) would the height look squished if I did

SplineResize(704,360)
Add Borders(8,120,8,120)

You see this does give the 720 x 480 spec for DVD but would it look squished. I forgot to tell you it is for 4:3 analog. I do have an HDTV. But I am NOT learning that JUST YET.

Or would the same source 352 x 480 Look better as this:

SplineResize(704,480)
AddBorders(8,0,8,0)
This is 720 x 480 when you add the borders but RESIZED at 704 x 480(10/11 spec) but when encoded had the 8:9 spec that we are talking about.


So my question is WHAT will define a good HEIGHT for the resize when adding BORDERS? I think that may be a little more clearer

Like if I did something NUTSO like:
SplineResize(704,200)
AddBorders(8,280,8,280)
This is 720 x 480 when you add the borders it probably destroys it I am thinking.

Is my question a little more clearer now: if ADDING borders, what height for a 352 x 360 source, would be the best and what would be like watching a straight line almost? Is there a technique used, if for example, had the 360 height that tells you--oh maybe I should increase it or descrease the height so when adding borders it would like good?

[Cornucopia]

A "352x360" source is Non-standard indeed! Most CIF (aka 1/4 D1) files are 352x240 (or PAL 352x288). This maps exactly 2x to 704x480 (or 704x576).

Hard to say what a 352x360 file's native PAR was supposed to be (or DAR for that matter). Think about it - it's Taller than it is Wide.!?

An NTSC CIF file like above would have the same PAR and DAR as the 704 D1 file (10:11 for 4:3). Widescreen CIF files (40:33 PAR with 16:9 DAR) are uncommon, but not "illegal" (and I have successfully created a working VCD to demonstrate).

Now, most 1/2 D1 files (aka 352x480) have a 20:11 PAR with a 4:3 DAR.

IOW, when I see something with a Non-standard height (standard NTSC/HD being = 240, 480, 720 or 1080), I first start thinking that whoever has this file has already done something WRONG with the source, and that what I'm hearing about is no longer the true source file...

What's the file's provenance?...

Scott

[jagabo]

The people at doom told me that (704 x 480) PADDED to meet 720 x 480 standards is something that the broadcasting industry uses for proffesional DVD's hence the 10:11 par

They are quoting the ITU 601 spec, not the DVD or MPEG 2 spec. I have't seen the DVD spec myself but from talking to someone who has, the DVD spec refers to the MPEG 2 spec regarding aspect ratios. The MPEG 2 spec is very clear: the aspect ratio refers to the full frame, not a 704x480 subsection of the 720x480 frame. See for yourself:

http://cutebugs.net/files/mpeg-drafts/is138182.pdf

As I said earlier, I've seen professionally mastered DVDs follow either spec. Nobody can see the 2 percent difference anyway.

Regarding your 352x360 video. My guess is it was originally a half D1 recording (352x480) of a letterboxed 16:9 source. Somebody removed the black bars leaving a 352x360 frame. If that's the case the proper resize for 16:9 DVD is:

WhateverResize(720,480)

Or, if you want to follow the ITU 601 spec:

WhateverResize(704,480)
AddBorders(8,0,8,0)

For 4:3 DVD:

WhateverResize(720,360)
AddBorders(0,60,0,60)

Or:

WhateverResize(704,360)
AddBorders(0=8,60,8,60)

But without seeing the actual video nobody can tell you what the correct resizing method is.

By the way, the pixel aspect ratio for a half D1 video is twice as wide as for full D1: 20:11.

[edDV]

But most editing/authoring software use ITU Rec.601 (D1) pixel aspect ratios which are the same for 704x480/576 and 720x480/576. These are used for both ATSC and DVB broadcasting.

for 4:3
704x480 or 720x480 0.9090...
704x576 or 720x576 1.0925...

I see there is a new wiki on the subject
http://en.wikipedia.org/wiki/Pixel_aspect_ratio

The classic
http://lipas.uwasa.fi/~f76998/video/conversion/

[jagabo]

Read the spec.

[Bonie81]

In addition to edDV

for 4:3
704x480 or 720x480 0.9090...
704x576 or 720x576 1.0925...

This is what vegas and AP follows.

Im general,
For PAL-DVD:
720 × 576 px (known as Full D-1), or, 704 × 576 px
352 × 576 px (known as the SEA), or, 352 x 288 px
For NTSC-DVD:
720 × 480 px (known as Full D-1), or, 704 × 480 px
352 × 480 px (known as the SEA), or, 352 x 240 px

[jagabo]

Unless someone can point out an updated MPEG 2 spec:

http://cutebugs.net/files/mpeg-drafts/is138182.pdf

aspect_ratio_information -- This is a four-bit integer defined in the Table 6-3.

aspect_ratio_information either specifies that the “sample aspect ratio” (SAR) of the reconstructed frame
is 1,0 (square samples) or alternatively it gives the “display aspect ratio” (DAR).

• If sequence_display_extension() is not present then it is intended that the entire reconstructed frame is intended to be mapped to the entire active region of the display. The sample aspect ratio may be calculated as follows:

SAR = DAR * horizontal_size / vertical_ size

The only time I've seen the sequence_display_extension used on a DVD is to define a 4:3 region for fullscreen display. It's always been 540x480. Note that 540/480 is 1.333. And that also implies the full 720x480 frame is 16:9 (1.333 * 720 / 540 = 1.777).

If you have a TV with a non-overscan mode, I urge you to go see what your upscaling DVD/Blu-ray players do. Mine upscale the full 720x480 frame to 1280x720 or 1920x1080 HDMI output.

[edDV]

Like you said, there are two conflicting specs and the difference is small. The ITU spec collection has consistency back to analog video and up to ATSC/DVB. There are historical reasons for 704 and 720. The MPeg DVD spec was pulled out of thin air for authoring convenience (or left optional). Probably a political decision. There was no compelling reason in 1994 for DVD aspect ratio to be consistent with analog or digital broadcasting. This left TV set manufacturers holding the bag to sort out the discrepancy. This probably explains why overscan is wider than it needs to be on HDTV sets.

[Krelmaneck]

The people at doom told me that (704 x 480) PADDED to meet 720 x 480 standards is something that the broadcasting industry uses for proffesional DVD's hence the 10:11 par

They are quoting the ITU 601 spec, not the DVD or MPEG 2 spec. I have't seen the DVD spec myself but from talking to someone who has, the DVD spec refers to the MPEG 2 spec regarding aspect ratios. The MPEG 2 spec is very clear: the aspect ratio refers to the full frame, not a 704x480 subsection of the 720x480 frame. See for yourself:

http://cutebugs.net/files/mpeg-drafts/is138182.pdf

As I said earlier, I've seen professionally mastered DVDs follow either spec. Nobody can see the 2 percent difference anyway.

Regarding your 352x360 video. My guess is it was originally a half D1 recording (352x480) of a letterboxed 16:9 source. Somebody removed the black bars leaving a 352x360 frame. If that's the case the proper resize for 16:9 DVD is:

WhateverResize(720,480)

Or, if you want to follow the ITU 601 spec:

WhateverResize(704,480)
AddBorders(8,0,8,0)

For 4:3 DVD:

WhateverResize(720,360)
AddBorders(0,60,0,60)

Or:

WhateverResize(704,360)
AddBorders(0=8,60,8,60)

But without seeing the actual video nobody can tell you what the correct resizing method is.

By the way, the pixel aspect ratio for a half D1 video is twice as wide as for full D1: 20:11.

I guess the bottom half is the answer to my question. But I would like to know why for example if when you encode a 352 x 360 source to an ITU 601 spec -- can you in layman's terms explain the relationship of what the 360 height means comparing it to a 480 height. What is the difference? The one relationship I can think of is 360 is saying is that the tv needs to cut slightly less than half so it can show on a 4:3 display. What is the relationship?

[manono]

What source comes as 352x360? Any examples? What kind of format is it, MPEG? Is it something you downloaded from somewhere?

[jagabo]

can you in layman's terms explain the relationship of what the 360 height means comparing it to a 480 height. What is the difference? The one relationship I can think of is 360 is saying is that the tv needs to cut slightly less than half so it can show on a 4:3 display. What is the relationship?

I don't understand your questions. Analog NTSC TV always displays 480 scan line (actually it's literally 485 scan lines but you only see about 440 of them because of overscan, 480 lines is the common storage format for digital video). One way or another your 360 line image has to be converted to 480 lines for display.

All that matters is what the display aspect ratio of your source is. Then you resize as appropriate for DVD. If your 352x360 is a half D1 video with the black borders cropped away then the pixel aspect ratio is 20:11. So the display aspect ratio is 352 / 360 * 20 / 11 = 1.778, or 16:9. If it's square pixel the proper display aspect ratio is 352 / 360 * 1 / 1 = 0.978.

[Krelmaneck]

Please keep in mind that this is a learning experience. I am going to keep to the ITU standards.


I am just thinking of some odd examples so that if I do have these kinds of videos, it will be less painful and I can just resize and send it to the encoder. It also is helping me to understand how one is suppose to resize better--but of course not perfect, as perfect may be hard since equipment changes.


could you explain what the picture is doing thus illustrate to me in words what exactly is happening when you take the height in 352 x 360 or even the height in a standard 640 x 360 and you either keep it as 360 or change it to 480?

[Krelmaneck]

can you in layman's terms explain the relationship of what the 360 height means comparing it to a 480 height. What is the difference? The one relationship I can think of is 360 is saying is that the tv needs to cut slightly less than half so it can show on a 4:3 display. What is the relationship?

I don't understand your questions. Analog NTSC TV always displays 480 scan line (actually it's literally 485 scan lines but you only see about 440 of them because of overscan, 480 lines is the common storage format for digital video). One way or another your 360 line image has to be converted to 480 lines for display.

All that matters is what the display aspect ratio of your source is. Then you resize as appropriate for DVD. If your 352x360 is a half D1 video with the black borders cropped away then the pixel aspect ratio is 20:11. So the display aspect ratio is 352 / 360 * 20 / 11 = 1.778, or 16:9. If it's square pixel the proper display aspect ratio is 352 / 360 * 1 / 1 = 0.978.

You might have answered THE question I had. So it is the RATIO that determines what the height is? So the par would be 10/11 for 704 x 360 thus allowing a 16:9 ratio. Which is acceptable for DVD. So if for any reason I get something that has a weird ratio that does not make sense like 0.6363633333. I just made that up, then I did things wrong. If the ratio= 1:1, I need to change it so I get a ratio of 4:3 or 16:9. 352 x 360 is acceptable for COMPUTERS but not for DVD. Anything that has square pixels need to be changed so that they either meet DVD or ITU 601 standards. I am just repeating what I just learned from you.


So as I take it we kind of want to get a ratio of 4:3 or 16:9. I think that makes sense. I think this post is coming to an end.


HAPPY THANKSGIVING.

[Bonie81]

What source comes as 352x360? Any examples? What kind of format is it, MPEG? Is it something you downloaded from somewhere?

manono
you should get either chinese. korean, or japanese (Ms. Mia Chou) girlfriend to watch 352x288 (not 352x360 in question), so you can watch at-least some cartoons like InuYasha.

[Cornucopia]

Ok, I'm going to take a stab at this...

Let's suppose someone's got a DVD with 1/2 D1 (aka 352x480) video on it, and it's a 4:3 image (DAR). That must mean the PAR is 20:11.
But let's pretend that the program shows a movie that is hard-letterboxed. When hard letterboxing a 4:3 height video to achieve a 16:9 video, one has to apply black bars of 60 pixels from the top and 60 pixels from the bottom, thus giving 352x360 (still in a 352x480 4:3 window).

<edit>:
When re-encoding to AVI, those black bars get cropped. And this now has a DAR of 16:9 but STILL a PAR of 20:11.

NOT square pixel. Even though most would expect an AVI to be square pixel. </edit>

Now, you want to get back to DVD-compliant specs, so...

You could do it in one of 2 ways.

A)
Take your 352x360 and re-apply the black borders, creating 352x480. Optionally, you could ALSO stretch the 352 to 704 or 720 so you end up with say 720x480 D1 (instead of 1/2 D1). Either way, you should encode the MPEG2 with the DAR of 4:3 (remember the 16:9 is created by the added letterbox borders).

or

B)
Take you 352x360 and stretch to either 352x480 or 704x480 (or 720x480, of course). Either way, you should encode the MPEG2 witha DAR of 16:9.

(A) has the benefit of NOT resizing the vertical, retaining that little bit extra of quality. Works great with 4:3 TVs, but will show as Windowbox (black on all sides) on a 16:9 TV (without some kind of Zoom function on the TV).
(B) has the benefit of being a modern, Anamorphic widescreen encoding (what most knowledgeable consumers expect from a widescreen DVD program) - it's applicable to either 4:3 TVs or 16:9 TVs. But you lose a little bit vertical rez in the stretch.

Hope this matches what you've encountered...

Scott

edit2: BTW, unless you're bitrate starved, D1 has much more functionality within DVDs than 1/2 D1.

[Krelmaneck]

What source comes as 352x360? Any examples? What kind of format is it, MPEG? Is it something you downloaded from somewhere?

This was a hypothetical post to help me understand what to do when it comes to resizing. I brought up the 352 x 360 example just to see how one deals with such a resizing. but that has been covered in the doom9 forum already. I made it hypothetical so that I can understand HEIGHT.. The actual video I am doing is 640 x 360. Again, there is no such video on my computer that I have been working on. Maybe I remember that number from along time ago.

But I think I have a good understanding now so I think this post has a solution and I may not ask any more questions on this post unless someone brings up something else.

[Krelmaneck]

Ok, I'm going to take a stab at this...

Let's suppose someone's got a DVD with 1/2 D1 (aka 352x480) video on it, and it's a 4:3 image (DAR). That must mean the PAR is 20:11.
But let's pretend that the program shows a movie that is hard-letterboxed. When hard letterboxing a 4:3 height video to achieve a 16:9 video, one has to apply black bars of 60 pixels from the top and 60 pixels from the bottom, thus giving 352x360. And this now has a DAR of 16:9 but STILL a PAR of 20:11.

NOT square pixel.

Now, you want to get back to DVD-compliant specs, so...

You could do it in one of 2 ways.

A)
Take your 352x360 and re-apply the black borders, creating 352x480. Optionally, you could ALSO stretch the 352 to 704 or 720 so you end up with say 720x480 D1 (instead of 1/2 D1). Either way, you should encode the MPEG2 with the DAR of 4:3 (remember the 16:9 is created by the added letterbox borders).

or

B)
Take you 352x360 and stretch to either 352x480 or 704x480 (or 720x480, of course). Either way, you should encode the MPEG2 witha DAR of 16:9.

(A) has the benefit of NOT resizing the vertical, retaining that little bit extra of quality. Works great with 4:3 TVs, but will show as Windowbox (black on all sides) on a 16:9 TV (without some kind of Zoom function on the TV).
(B) has the benefit of being a modern, Anamorphic widescreen encoding (what most knowledgeable consumers expect from a widescreen DVD program) - it's applicable to either 4:3 TVs or 16:9 TVs. But you lose a little bit vertical rez in the stretch.

Hope this matches what you've encountered...

Scott

Hi this was already convered in the doom 9 forum. This is where PAR get INVERSED. The par is 10/11

480 Target height/Source Target heigh = horizontal scaling
Horizontal scaling x source width x INVERSED PAR =new width

480/360= 1.33333333333

Therefore 1.3333333333333 (352) (11/10) = 516 NEW WIDTH

I found it.

SplineResize(516,480)
AddBorders(102,0,102,0)

[Cornucopia]

Not for DVD you shouldn't - it's not compliant.

Plus, in my scenario, the PAR is 20:11. And it shouldn't be inversed.

So it wouldn't be 512, it would be 1.3333 * 352 * 20 / 11 = 853. If that figure sounds familiar it should be - that's what a SQUARE PIXEL widescreen width would be if the vertical was 480.

But, again, since DVDs are not SQUARE PIXEL, you're missing the final component in your equation. When doing a scaling function keeping the DAR the same, you need to have both the source PAR and the target PAR in there.

So that should look like this:

(Generalized)

Source W / Source H * Source PAR = Source DAR
and
Target W / Target H * Target PAR = Target DAR

when Source DAR and Target DAR are supposed to be the same (in this case 16:9), that gives:

Source W / Source H * Source PAR = Target W / Target H * Target PAR

To solve for Target W, you would rearrange to get:

Target W = Source W * Source PAR / Target PAR * Target H / Source H

Pluging that in...

Target W = 352 * 20/11 / 40/33 * 480 / 360 = 704

Scott

[Krelmaneck]

Not for DVD you shouldn't - it's not compliant.

Plus, in my scenario, the PAR is 20:11. And it shouldn't be inversed.

So it wouldn't be 512, it would be 1.3333 * 352 * 20 / 11 = 853. If that figure sounds familiar it should be - that's what a SQUARE PIXEL widescreen width would be if the vertical was 480.

But, again, since DVDs are not SQUARE PIXEL, you're missing the final component in your equation. When doing a scaling function keeping the DAR the same, you need to have both the source PAR and the target PAR in there.

So that should look like this:

(Generalized)

Source W / Source H * Source PAR = Source DAR
and
Target W / Target H * Target PAR = Target DAR

when Source DAR and Target DAR are supposed to be the same (in this case 16:9), that gives:

Source W / Source H * Source PAR = Target W / Target H * Target PAR

To solve for Target W, you would rearrange to get:

Target W = Source W * Source PAR / Target PAR * Target H / Source H

Pluging that in...

Target W = 352 * 20/11 / 40/33 * 480 / 360 = 704

Scott

In the way I was taught, the dar is calculated first. 10/11. The 4:3 number here is a conicidence. The 1.33333333333 is the scaling factor.

And then:

SplineResize(516,480) FOUND TYPO: EDIT.
AddBorders(204,0,204,0)

720 x 480 is super compliant with DVD.

HOLD ON. That would be toooooooooooooooo much blackborders, right?

maybe I should burn it with the 204 borders to see what it looks like.

[manono]

What source comes as 352x360? Any examples? What kind of format is it, MPEG? Is it something you downloaded from somewhere?

This was a hypothetical post to help me understand what to do when it comes to resizing.

Then come back when you come across such a video.

The actual video I am doing is 640 x 360. Again, there is no such video on my computer that I have been working on.

Yeah, but that size isn't all that uncommon. Since it's 1.778:1, what's the big deal? A little knowledge is a dangerous thing. If you resize using ITU then:

FavoriteResizer(704,480)
AddBorders(8,0,8,0)

Otherwise:

FavoriteResizer(720,480)

And encode as 16:9. Or just let FitCD do all the figuring for you.

[manono]

What source comes as 352x360? Any examples? What kind of format is it, MPEG? Is it something you downloaded from somewhere?

manono
you should get either chinese. korean, or japanese (Ms. Mia Chou) girlfriend to watch 352x288 (not 352x360 in question), so you can watch at-least some cartoons like InuYasha.

Hehe, I have plenty of 352x288 25fps VCDs. But none are Inuyasha.

[Krelmaneck]

If PAR=DAR/sar, why can't sar be 160/129 for 516/480?

4/3 / 516/480
4/3 (480/516)

1/1 160/129

And if 160/129 is a par, 516 x 480 could equal a strange 4:3 image

516/480 x 160/129

4 /3 (1/1) = 1.333333333333333


Thus just add borders to LanzcosREsizer(516,480) Addborders(204.0,204,0)

I did not CATCH THIS MISTAKE it is AddBorders(102,0,102,0) I accidently put 204 make it 408. That was a big mistake. But 102 is the number.





So in a strange way, isn't 516/480 = 1.3333333 yeah, not DVD until you add borders, but still 4:3?

[jagabo]

The aspect ratio flag in MPEG 2 only supports four values:

1:1 PAR
4:3 DAR
16:9 DAR
2.21:1 DAR

Of those four possible aspect ratios, DVD only supports two. 4:3 DAR and 16:9 DAR. NTSC DVD is limited to frame sizes of 720x480, 704x480, 352x480, and 352x240. Satisfying both those restrictions limits the possible pixel aspect ratios.

4:3 DAR, 720x480: 8:9 PAR
4:3 DAR, 704x480: 10:11 PAR
4:3 DAR, 352x480: 20:11 PAR
4:3 DAR, 352x240: 10:11 PAR

As I understand it, 16:9 DAR is further limited to only 720x480 and 704x480 frame sizes:

16:9 DAR, 720x480: 32:27 PAR
16:9 DAR, 704x480: 40:33 PAR

Then there's PAL...

[Krelmaneck]

The aspect ratio flag in MPEG 2 only supports four values:

1:1 PAR
4:3 DAR
16:9 DAR
2.21:1 DAR

Of those four possible aspect ratios, DVD only supports two. 4:3 DAR and 16:9 DAR. NTSC DVD is limited to frame sizes of 720x480, 704x480, 352x480, and 352x240. Satisfying both those restrictions limits the possible pixel aspect ratios.

4:3 DAR, 720x480: 8:9 PAR
4:3 DAR, 704x480: 10:11 PAR
4:3 DAR, 352x480: 20:11 PAR
4:3 DAR, 352x240: 10:11 PAR

As I understand it, 16:9 DAR is further limited to only 720x480 and 704x480 frame sizes:

16:9 DAR, 720x480: 32:27 PAR
16:9 DAR, 704x480: 40:33 PAR

Then there's PAL...

True. But when you take a video and resize it the final result that it put through then encoder must be one of these specs. But when you resize and add borders as LONG as they match up to one these specs it all good.

So if you did this avisynth script the encoder see's it as 720 x 480

SplineResize(516,480)
Addborders(102,0,102,0)

So the AVS script that is posted above once sent through the encoder will see it as 720 x 480. Just FLAG the mpeg for 4: 3. Or type in the script above and send it to Gspot and it will say 720 x 480. CORRECTION: Gspot won't show you the stats if you just feed in a AVS script, so kill that idea. Bu still 516 +102 + 102= 720. 204 pixels of black bars are added to meet the standard. 102 on the left. And 102 on the right.


And right now LITERALLY I just encdoded this;

LanzcosResize(704,360)
AddBorders(8,60,8,60)

This was from a 640 x 360 source Because 640 x inversed par 11/10 (instead of 11/10) = 704

I opened IFOedit and selected DVDauthor. And it said the mux was acceptable and it made a VOB with no errors..



PS--a 352 x 360 may be hard to find. But this was a hypothetical post, a what if post if you may.

[Cornucopia]

So you've only been talking hypothetically the whole time? No wonder it's been so convoluted!

IIWY, I'd not only try to get the gist of those Doom9 shortcuts, but also to see the big picture relationships, because if you understand those you can solve most any resize/encode problem.

It's a universal rule that "Width/Height * PAR = DAR". So any resize calculations have to take this rule into account. It's a friggin' high school algebra problem, plugging in variables, rearranging to get the element(s) you want all on one side, and solving for an unknown.

Whatever shortcuts you gathered from Doom9 (as knowledgeable as they often are) are only accurate if, for example, they've simplified the equation by cancelling things out under special circumstances. Just like Newtonian physics is a limited subset of Einsteinian physics, where you don't need to count certain things because they either cancel out or are insignificant.

*****************************

What I want to know is, why are we still having this conversation when it's basically a rehash of a conversation we (you, me, jagabo, edDV, etc) had last August, and before that in 2007? I don't think you're dense or anything, but I'm beginning to think you're just baiting/trolling...

Let me know when you've got a true existing problem, and when you give us the full scoop, I'll get back to you.

Scott