How to crop correctly. A guide using Megui.

[Jeremy Duncan]

How to crop your video using megui avs script creator
_______________________________________________________________

Watch youtube video guide (http://www.youtube.com/watch?v=VJNIxXIgH-w)


Step 1: Initializing the avs script editor to then use either method 1 or method 2
_______________________________________________________________

- From the megui tool tab, click avs script creator.

- Open the avs script creator and load your avs file. Your avs file should look like this. Notice nor resizing or cropping in the code:

directshowSource("C:\Users\red\Desktop\Blade Runner.GRF",audio=false,fps=23.976)

- From the Input Dar, go to "Select AR".
If the dvd box says 2.35:1, then type in 2.35
If the dvd box says the aspect ratio is 1.78:1, then type in 1.78
Then press ok.

Method 1
_______________________________________________________________

- Check the "Resize", "Suggested resolution mod16", "Crop" boxes.

- Assuming your source resolution is 720, 480 or 720, 576 Widescreen, And there is 8 pixel black bars on the left and right side of the video, change the 720 to 704 using the down arrow to the left of 720. Pressing it once will change the resolution to 704.

- Assuming the video is 720, 480 or 720, 576 Widescreen and there is no 8 pixel black bars on the left and right side, then keep the resolution to 720.

- Click the "Clever anamorphic encoding"box.

- You can now save the file.
Open the saved file and copy and paste the code you need to the avs you opened in the avs script creator process.

I needed to get 1.78:1 and after doing this my created avs looked like this:
# Set DAR in encoder to 16 : 9. The following line is for automatic signalling
global MeGUI_darx = 16
global MeGUI_dary = 9
Import("C:\Users\canteen\Desktop\test run2.avs")
#deinterlace
crop( 0, 0, 0, 0)

LanczosResize(704,464) # Lanczos (Sharp)
#denoise

And my working avs looked ike this after all this work was done and I'm ready to start encoding:

mpeg2source("C:\Users\canteen\Desktop\afro.d2v")
global MeGUI_darx = 16
global MeGUI_dary = 9
LanczosResize(704,464)

Method 2
_______________________________________________________________

- Assuming your source resolution is 1920x 1080 High Definition.

- Check these boxes:
Resize, Suggested resolution mod 16.
This will change the resolution of the 1920, 1080.

- Uncheck Suggested resolution mod 16.

- Check the crop box.

- Click Auto crop.

- Save the file.

- Copy and paste the results into your working avs file as done in method 1.

______________________________________________________


This picture shows how to initialize avs script creator to then do either of the two methods below

http://thumbnails17.imagebam.com/4044/b1793440437963.gif (http://www.imagebam.com/image/b1793440437963)

Method 1
http://thumbnails15.imagebam.com/4044/dd503840437964.gif (http://www.imagebam.com/image/dd503840437964)

method 2
http://thumbnails.imagebam.com/4044/74622840437966.gif (http://www.imagebam.com/image/74622840437966)


Comparison pictures below

http://thumbnails.imagebam.com/4044/6b8a9540438256.gif (http://www.imagebam.com/image/6b8a9540438256)

- You may be asking which method is the best one?
There is no Best method is the answer. Try a method. When have a finished avs with the values you got from the avs script editor, open the avs with megui, and there will be a picture pop up and it will show the aspect ratio of that picture.

If you do not think the aspect ratio shown in the picture is good enough, then try the other method. Simple as that. :)

- About cropping. If you select a video using your avs, and when the video screen pops up,and that video has a miniature video picture on the screen that is not what the rest of the movie resolution is.
Then when you crop using the avs script creator it will crop out the black border surrounding that miniature picture.
So you need to have a picture the size of the main movie in the pop up box when you start the avs script creator.

Note
Below is the original post for reference purpose. Above the line is my edited post with my solution I found

________________________________________________

sample vob (http://www.mediafire.com/?tn5lmnzyjzy)

I want to resize the video to these three resolutions.
Not all at once in the same encode though.

The first resolution is 720x480, or ntsc sd dvd
The second resolution is 720x576 or pal dvd
The third resolution is 1080p, or 1920x1080

This is the solution I have now and I think it's wrong?

LoadPlugin("C:\Program Files\AviSynth 2.5\plugins\DGDecode.dll")
setmtmode(5)
mpeg2Source("C:\Users\Red\Desktop\test run.d2v")
setmtmode(2)
a= last
b=a.Spresso()
SeeSaw(a,b)
LimitedSharpenFaster(strength=11)
LimitedSharpenFaster(strength=11)
super = MSuper(pel=2,hpad=4,vpad=4)
backward_vec = MAnalyse(super,chroma=false, blksize=16, isb = true, search=5, searchparam=1)
forward_vec = MAnalyse(super, chroma=false, blksize=16)
MFlowFps(super, backward_vec, forward_vec, num=60, den=1, mask=1, ml=49)
distributor()

Crop(0,0,-0,-0)
Spline36Resize(720,480)

[2Bdecided]

It's FHA 16x9.

Not sure about the pointless crop line, but what else can go wrong with the aspect ratio? Just resize to the desired resolution, and make sure you flag the SD versions as 16x9.

Cheers,
David.

[Adub]

Yeah, I believe if you want to reach your pal resolution you can just pad it with black bars. That way your aspect ratio doesn't change and you get your desired resolution.

[2Bdecided]

No, no black bars, just resize!

Cheers,
David.

[Jeremy Duncan]

This is what I'm using now for 16:9 1.78:1 aspect ratio.

Ntsc

1.78:1

LoadPlugin("C:\Program Files\AviSynth 2.5\plugins\DGDecode.dll")
mpeg2Source("C:\Users\Red\Desktop\test run.d2v")

Spline36Resize(848,480)

Pal

1.78:1

LoadPlugin("C:\Program Files\AviSynth 2.5\plugins\DGDecode.dll")
mpeg2Source("C:\Users\Red\Desktop\test run.d2v")

Spline36Resize(1024,576)
_____________________

Now what I am thinking of doing is doubling the resolution and I'm wondering if it needs anything like addborders added to the code.
if I do then please post the code it needs. :)
The code with double the resolution is below.

Ntsc

1.78:1

LoadPlugin("C:\Program Files\AviSynth 2.5\plugins\DGDecode.dll")
mpeg2Source("C:\Users\Red\Desktop\test run.d2v")

Spline36Resize(1696,960)

Pal

1.78:1

LoadPlugin("C:\Program Files\AviSynth 2.5\plugins\DGDecode.dll")
mpeg2Source("C:\Users\Red\Desktop\test run.d2v")

Spline36Resize(2048, 1152)

[midnightsun]

did you not say you wanted to resize to ntsc/pal DVD resolution? If so what's with 848x480 and 1024x576? Follow 2Bdecided's advice if that's your goal.

The last 2 pieces of code are ok, just remember they are for square pixels though.

[Jeremy Duncan]

did you not say you wanted to resize to ntsc/pal DVD resolution? If so what's with 848x480 and 1024x576? Follow 2Bdecided's advice if that's your goal.

The last 2 pieces of code are ok, just remember they are for square pixels though.

I use megui and don't know how to follow 2Bdecided's advice.
Where would this be set in megui I wonder?

I have a request. Could you or somebody translate my code in post #5 into non-square pixel resolution? :)

[2Bdecided]

MeGUI makes DVDs?!

[Jeremy Duncan]

MeGUI makes DVDs?!

I don't think so. For that you would use hc enc and make a mpeg2 then use a dvd builder to make the vobs.

[2Bdecided]

Yes, I know that - but you started off requesting DVD resolutions, then asked how to do it in MeGUI.

What are you trying to do?

Cheers,
David.

[Jeremy Duncan]

I ripped different aspect ratio sd dvd's then opened then in ripbot264 and got the cropping and resize resolutions for hd and sd at different aspect ratios.

The resolution of the 1.78:1 had no cropping applied or fancy resolution for hd or ntsc sd dvd. So I used the code in post five, section 1.
Spline36Resize(848,480)
Spline36Resize(1024,576)

I read these resolutions were for 16:9 online somewhere.
So I decided that doubling them would be a good idea then somebody here said doubling them still kept the 1.78:1 aspect ratio but at hd, or square pixels.
So I asked him or somebody for the non-square pixel version. :)

[kemuri-_9]

NTSC dvds are 720x480, so doubling that gets you 1440x960.
both resolutions need a pixel stretch of 32:27 to get 16:9 AR which you add in the encoder/muxer options.

the actual display resolutions at the 32:27 pixel stretch are
853(+1/3)x480 and 1706(+2/3)x960 respectively

PAL dvds are 720x576 iirc, so doubling that gets you 1440x1152.
both resolutions need a pixel stretch of 64:45 to get 16:9 AR (which again you add in the encoder/muxer options).

the actual display resolutions at the 64:45 pixel stretch are
1024x576 and 2048x1152 respectively

[2Bdecided]

I might be being incredibly thick, but I don't think that told us what you are trying to do.

I was expecting an answer like: I'm trying to burn them to DVD, I'm trying to upscale them and put them on BluRay, I'm trying to watch them at optimum quality on my PC, I'm trying to upload to YouTube HD - you know, something like that!


For as much as you've asked, kemuri-_9 has answered - I just don't understand why you'd want to do this.

Cheers,
David.

[Jeremy Duncan]

What am I trying to do?
I said that ripbot264 showed the crop and resize values for these:
sd dvd: ntsc, pal.
HD: 1080p, 720p

I ran into a problem because for 1.78:1 sd dvd, ntsc. The values shown in ripbot264 were simple with no cropping so I didtrusted this and looked online for the info ripbot264 should have given me and couldn't find it, so I decided to ask here for that info. :)
That's why I said sd dvd and 1080p.

I'll try and figure out how to interprete kemuri's answer later.
Edit,

Where in megui do I set it to 32:27, 64:45?
What is the sd dvd pal and ntsc sar for aspect ratios: 2.35:1, 2.40:1, 1.85:1
What is the sar for square pixel hd 1080p: 2.21:1, 1.78:1, 2.35:1, 2.40:1?
I looked for a wiki for the answers but couldn't find one, so I'm hoping you may post the answers.

[kemuri-_9]

Where in megui do I set it to 32:27, 64:45?

I don't use meGUI, but there's either a specific section that deals with aspect ratio, or you add the proper parameter to the encoder command line.


What is the sd dvd pal and ntsc sar for aspect ratios: 2.35:1, 2.40:1, 1.85:1
What is the sar for square pixel hd 1080p: 2.21:1, 1.78:1, 2.35:1, 2.40:1?
I looked for a wiki for the answers but couldn't find one, so I'm hoping you may post the answers.

these can all be mathematically calculated, as that's what they are after all - fractions.

a ntsc dvd has a 720x480 resolution, which is an AR of 3:2 (3/2)
PAL is 720x576, so its AR is 5:4 (5/4)

take the desired display aspect ratio you want to calculate the pixel stretch for and divide it by the source AR:

i.e.
(16/9) / (3/2) = 32:27
(16/9) / (5/4) = 64:45

2.35 / (3/2) = 47:30
2.35 / (5/4) = 47:25

and so on...
then naturally multiplying the width of the source aspect ratio by the pixel stretch gets you the display width:

720(x480) * 47/30 = 1128x480
720(x576) * 47/25 = 1353(+3/5)x576

which is what you would need to resize to for encoding as square pixels

[Jeremy Duncan]

I don't use meGUI, but there's either a specific section that deals with aspect ratio, or you add the proper parameter to the encoder command line.



these can all be mathematically calculated, as that's what they are after all - fractions.

a ntsc dvd has a 720x480 resolution, which is an AR of 3:2 (3/2)
PAL is 720x576, so its AR is 5:4 (5/4)

take the desired display aspect ratio you want to calculate the pixel stretch for and divide it by the source AR:

i.e.
(16/9) / (3/2) = 32:27
(16/9) / (5/4) = 64:45

2.35 / (3/2) = 47:30
2.35 / (5/4) = 47:25

and so on...
then naturally multiplying the width of the source aspect ratio by the pixel stretch gets you the display width:

720(x480) * 47/30 = 1128x480
720(x576) * 47/25 = 1353(+3/5)x576

which is what you would need to resize to for encoding as square pixels

:confused:

I wish I knew how to do what your asking me to do but that lesson is over my head...No way I'm going to get my answers doing that math on my own.
I guess if I stared at it for a hour or so it would make sense but not just at looking at it. :p

Could you do it for me please...?

[Alex_ander]

It is much easier to understand and calculate outside the unnecessary 'square/non-square' theory with its PAR'/DAR's/SAR's.

1.When you read about 'square pixels' this means that (with the type of file in question, like avi, full-res. HDTV etc.) the aspect ratio of a picture is completely defined by pixel numbers stored for its horizontal/vertical dimensions and you can use those numbers to calculate it or set it in the file you create within that type. A pixel itself doesn't have any geometrical properties, it's an artificial assumption derived from properties of the whole picture.

2.When you read about 'non-square pixels' this means that in a particular type of file (e.g.MPEG2 for SD DVD, DV files from camera etc.) the stored pixel numbers don't represent at all the AR of the picture (AR here and below means the same as the often used DAR). In that case the AR is independently defined by a separate parameter stored in video file: the AR flag (in case of DVD there are just 2 standard values: 4:3 or 16:9). Those AR flags are followed by a player independently from ratio of the stored numbers (mpeg2 stored pixel numbers can be 720x480/576, 480x480/576 - SVCD, 544x480/576 - DVB; they all can be 16:9 by AR).

In case 1 your resizing calculations are quite transparent.
In case 2 they are as simple if the originally shot video is either 4:3 or 16:9 - then you resize what you have to the standard numbers like 720x480 (no matter what the ratio of those numbers is) and set one of those two AR versions in your encoder. That is what 2BDecided already explained in the beginning of the thread.

In case original video is different from both 4:3 or 16:9 (like 2,35:1), you'll have to reduce image height + add horizontal borders inside a 720x480/576 image. This can be done using simple proportions known from primary school, still without involving tables of fractional numbers, PAR's etc. And you'll keep understanding what's happenning while you calculate it. E.g. for letterboxing a 2.35:1 image within 1.777:1, the new height will be:
480x1.777/2.35=363=~360 (it's a good rule to round it to a multiple of 8 or 16 when possible); then you add borders like 56+64 (mod 8).

There can also be considerations for setting DVD image width 720 or 704 (with or without borders) but they don't have influence on the above image height calculation.

[2Bdecided]

I still don't get what you're trying to do (what's your intended output?), but anyway...

I ran into a problem because for 1.78:1 sd dvd, ntsc. The values shown in ripbot264 were simple with no cropping so I didtrusted this and looked online for the info ripbot264 should have given me and couldn't find it, so I decided to ask here for that info. :)
That's why I said sd dvd and 1080p.

It's kind of trivial to grasp that if you have a source without black bars, and you want to keep all of the original image, then you don't need to do any cropping.

The sample you posted had no black bars. It's 16x9. You want 16x9. So ripbot264 didn't want to crop it.

Makes sense to me.

Cheers,
David.

[Gavino]

I guess if I stared at it for a hour or so it would make sense but not just at looking at it. :p
Well, it could be the most productive hour you've ever spent. :)
Once you understand how it works, you will be able to use that understanding in every future project you do (rather than just following a recipe).

BTW like 2Bdecided, I don't get what you're trying to do either. :stupid:

[Jeremy Duncan]

It's kind of trivial to grasp that if you have a source without black bars, and you want to keep all of the original image, then you don't need to do any cropping.

The sample you posted had no black bars. It's 16x9. You want 16x9. So ripbot264 didn't want to crop it.

Makes sense to me.

Cheers,
David.

Then, may I ask. If I don't need to do any cropping then I also do not need to do Addborders()?

I quoted your reply because I did not know this.

Edit,

You ask what my intended output is? It is a resolution at a aspect ratio, the file format is not important to me.
I want to be able to rip a dvd, look at the chart i put together and get the correct cropping and resize to get the sd dvd at ntsc or pal.
For instance. I chose sd dvd ntsc (720, 480) at 2.35 aspect in ripbot264 and it gave me this avisynth code:
Crop(video,0,56,-0,-62)
Spline36Resize(video,640,272)

As you can see the resolution is different than 720x480.
So there you go, get it yet? :)

Gavino,

I was going to devote some time to learning how to manually do the math, but now I see ripbot264 answers are correct then I don't need to do the work myself. :p

[Wilbert]

If i understand you correctly: your source is dvd and your target is dvd. Why do you want to crop and resize? In general, if you do this because you want to crop the black borders, you will also need to crop a part of the active picture (to get your DAR 4x3/16x9 again). Is this what you are trying to do?

[Jeremy Duncan]

I thought that keeping the resolution the same during encoding as it is on the dvd (720, 480), that the aspect ratio would be off.

I thought the encoder uses square pixels at 720, 480, so the non-square pixels from the vob when encoded would be treated as square pixels by the encoder.
So then I though that through cropping and resizing and addborders the encoder was forced to use non-square pixels.

That's why I was confused when ripbot264 used the dvd resolution. Why use dvd resolution in the encode when the encode treats non-square pixels as square pixels I thought.
This must be wrong.
And that's how this thread started with me asking for cropping and resize for sd dvd ntsc 1.78:1 aspect ratio, which uses non-square pixels.

[kemuri-_9]

you tell the encoder whether to add a pixel stretch flag to the stream or not.
not specifying a pixel stretch flag is then interpreted as square pixels on the decoder side.
i.e.
flagging 720x480 with 32:27 pixel stretch -> display as 853x480 (16:9)
flagging 720x480 with 8:9 pixel stretch -> display as 640x480 (4:3)
not flagging 720x480 at all (or flagging with 1:1 stretch) -> display as 720x480 (3:2)

in all cases it's the same 720x480 resolution in the resulting bitstream by the encoder, but they're just played back slightly differently.
...
this is all granted that the container and decoder you use both can and does respect the pixel stretch flag that was set by the encoder...
(*cough* AVI fail *cough*)

[Jeremy Duncan]

I updated my first post. It shows how I got the crop value ripbot264 gave me using megui's avs script creator.
Ripbot264 used my vc1 1080p blu ray avs.

I then applied that method to my afro samurai sample ans I got this code:

loadplugin("C:\Program Files\AviSynth 2.5\plugins\dgdecode")
mpeg2source("C:\Users\canteen\Desktop\afro.d2v")

spline64resizeResize(720,400)

Here is a comparison picture. The one one the left is at resize 720, 480, the one on the right uses this code above:

http://thumbnails17.imagebam.com/4040/7b0d4240397029.gif (http://www.imagebam.com/image/7b0d4240397029)

[kemuri-_9]

what are you trying to say/prove with that comparison?

you're comparing two pictures of different AR:
one that's lost some vertical resolution to use square pixels to more accurate AR
and one that's maintained its original resolution using non-square pixels, so it has inaccurate AR.

so imo, the comparison is void,
if you wanted a realistic comparison, you would of resized the 720x480 frame to 853x480
and compared that against the 720x400 frame (which is still incorrect AR, 704x400 would be more accurate)

[2Bdecided]

You ask what my intended output is? It is a resolution at a aspect ratio, the file format is not important to me.Well it should be - some formats only allow specific aspect ratios.

I want to be able to rip a dvd, look at the chart i put together and get the correct cropping and resize to get the sd dvd at ntsc or pal.
For instance. I chose sd dvd ntsc (720, 480) at 2.35 aspect in ripbot264 and it gave me this avisynth code:
Crop(video,0,56,-0,-62)
Spline36Resize(video,640,272)Yes, it crops the black bars away, and resizes (down) to square pixel (nearest mod 16 values).

So that's what you want to do?

If so, why do you talk later about adding borders?! You want 720x480 and square pixels?! That's pointless - there's a justification for one or the other - not both! If you've found a justification for having 720x480 containing a square pixel image, it probably means you've got a deep misunderstanding of something.

(If this isn't what you're doing, my apologies!).


I think it's very misleading to rename this thread "a guide" ;)

Still, if you're now happy with what RipBot is giving you, I guess everyone's happy. There's no question left.

Cheers,
David.

[Jeremy Duncan]

if you wanted a realistic comparison, you would of resized the 720x480 frame to 853x480
and compared that against the 720x400 frame (which is still incorrect AR, 704x400 would be more accurate)

I have done so. I added the picture comparison to the first post.
Megui would not open a resize with the value you gave, so I changed it to 852, 480.

2Bdecided,

I'm not sure what you don't understand.
I have told Wilbert what I was trying to do and told you a few times. Maybe we have a language barrier that prevents me from enlightening you on what I am trying to do.

I have updated the first post. :)

[2Bdecided]

I've just watched your YouTube videos.

In several places, I think you're making things more complicated than they need to be, for no good reason that I can see.

Your choice of destination resolution seems quite arbitrary - and resizing 720 down to 704 when you're resizing to square pixels makes no sense at all. You'd normally keep one or the other dimension the same, or (if needed) resize to something very different - resizing to something slightly different is odd.

Cheers,
David.

[Jeremy Duncan]

2Bdecided,

Can you rephrase yourself again. I don't follow your logic completely.

There is a encoding guide and a ffdshow guide, as well as a dll guide in the youtube site.
Each guide has nothing to do with each other.
The encoding guide has nothing to do with the ffdshow guide.

I know I use ffdshow for hd resolutions, but that doesn't mean I can't encode using sd resolutions.
I though about encoding at hd resolutions using megui avs script creator so I can get the aspect ratio correct at hd resolutions using sd source, but I don't know how.
So I kept the encoding guide for sd dvd using the resolution the avs script creator gave it when I load the source into it. :)

[2Bdecided]

So I kept the encoding guide for sd dvd using the resolution the avs script creator gave it when I load the source into it. :)Unless you mean something else, what you've said above simply isn't true - it started off with a 720 pixel width, and you explicitly changed it to 704. I know you did this because you've told us, and you show it in your video.

Cheers,
David.

[Jeremy Duncan]

Unless you mean something else, what you've said above simply isn't true - it started off with a 720 pixel width, and you explicitly changed it to 704. I know you did this because you've told us, and you show it in your video.

Cheers,
David.

The doom9 guide says to use 704:
link (http://www.doom9.org/index.html?/capture/par.html)

"704 x 480 1.3370 * 480 / 704 = 0.9116 This is NTSC DVD PAR"

Maybe you can rephrase yorself more so i can better understand what we are talking about? :)

[Inspector.Gadget]

You haven't accounted for overscan, and then you're into the whole software/ITU debate, and then you're off the edge of a cliff.. ;)

[2Bdecided]

We're going around in circles Jeremy - I think we established about a page back that you weren't encoding for a DVD, and were encoding square pixels.

So what the doom9 guide says about D1 (=DVD resolution) encoding, which by definition gives non-square pixels, isn't relevant.



And while I usually argue for proper ITU 704-pixel based encoding when you're coming from VHS or something with visible 8-pixel black orders, a 720-pixel wide DVD with absolutely no black borders (which is what this thread started with) has to be kept at 720, and is probably best treated as if the full 720 pixels define the aspect ratio.

Cheers,
David.

[Comatose]

You really should drop the guide making thing until you're well informed on what you're trying to do...

[Jeremy Duncan]

a 720-pixel wide DVD with absolutely no black borders ...is probably best treated as if the full 720 pixels define the aspect ratio.

Cheers,
David.

I now know. Thank you for sharing this info.

With borders I use the 704 rather than 720 though, right?

[2Bdecided]

With borders I use the 704 rather than 720 though, right?If there are ~8 pixel borders each side, then yes. If there are only borders top and bottom, then no.

[Jeremy Duncan]

If there are ~8 pixel borders each side, then yes. If there are only borders top and bottom, then no.

Are you saying if there is only top and bottom borders that the resolution is 704, or 720?

And if there are borders all around ~8 pixel each side the resolution should be 704 or 720?

By reading the doom9 guide the pal resolution stays at 720.
Is this correct, or not? Please clarify. :)

[kemuri-_9]

If there are ~8 pixel borders each side, then yes. If there are only borders top and bottom, then no.

i've never particularly seen such 4-way overscan....
but does it actually exist, and even to such an extent as that?

Are you saying if there is only top and bottom borders that the resolution is 704, or 720?

it would naturally crop to 720x464 for that vertical overscan situation


And if there are borders all around ~8 pixel each side the resolution should be 704 or 720?

think about it for just a minute...

[2Bdecided]

"each side" was misleading English - I meant exactly this...

For 720 pixel-wide source, if there are ~8 pixel borders left and right, then use 704. If there are no borders left and right, then use 720.

...and being more picky, I've often argued that the ITU PAR is correct (which means that the aspect ratio is defined by the centre 704 pixels, even if you have the full 720 present) - this is what all video standards say - but I've now verified that several video processors (including those used by the BBC!) fill the 720 pixels with content in such a way that the full 720 pixels define the aspect ratio - in direct contradiction of the ITU specs - the "extra" 8 pixels each side aren't extra at all - they're part of the true 16x9 or 4x3 image.

Cheers,
David.

[DarkT]

but I've now verified that several video processors (including those used by the BBC!) fill the 720 pixels with content in such a way that the full 720 pixels define the aspect ratio - in direct contradiction of the ITU specs - the "extra" 8 pixels each side aren't extra at all - they're part of the true 16x9 or 4x3 image.

Cheers,
David.

So basically, the whole idea of going to ~873 to avoid contortion can be... making things worse in soem cases?

[Ghitulescu]

If we discuss analog, there is one value set: 711 samples per line.

But 711 / 16 is 44.4375, that means it's no good for MPEG encoders. The next 16MOD values are 704 and 720. So far I know MiniDV is 704 (some camcorders fill however the missing 16 pixels with black) while the DVD allows both (720 seems to be more present).

The difference in PAR is negligible between 704 and 720. Important is not to change inutilly the PAR/DAR, the rest is pure philosophy.

[maldino800]

Hello.
Can you tell me step by step please,how I can change the reseluotion 720p( 1280 * 544 )mkv file to full reselution 720p(1280 * 720) ???

[Ghitulescu]

Hello.
Can you tell me step by step please, how I can change the resolution 720p (1280 * 544) mkv file to full resolution 720p (1280 * 720) ???

AddBorders() in Vdub and relatives or use uncropMKV by deank. Reencoding is necessary.

[maldino800]

AddBorders() in Vdub and relatives or use uncropMKV by deank. Reencoding is necessary.

But vdub can open mkv files?how?

[Ghitulescu]

But vdub can open mkv files?how?

The answer is here -> http://forum.doom9.org/forumdisplay.php?f=22
or here -> http://www.videohelp.com/forum/archive/mkv-problems-in-virtualdub-t332447.html

For uncropMKV -> http://forum.doom9.org/showthread.php?t=145905.

[maldino800]

The answer is here -> http://forum.doom9.org/forumdisplay.php?f=22
or here -> http://www.videohelp.com/forum/archive/mkv-problems-in-virtualdub-t332447.html

For uncropMKV -> http://forum.doom9.org/showthread.php?t=145905.
Ok.thanks for help.

[Jeremy Duncan]

I updated the guide, method one with this editing:

"- Assuming your source resolution is 720, 480 or 720, 576 Widescreen, And there is 8 pixel black bars on the left and right side of the video, change the 720 to 704 using the down arrow to the left of 720. Pressing it once will change the resolution to 704.

- Assuming the video is 720, 480 or 720, 576 Widescreen and there is no 8 pixel black bars on the left and right side, then keep the resolution to 720."

I hope it's correct.

[2Bdecided]

If we discuss analog, there is one value set: 711 samples per line.

But 711 / 16 is 44.4375, that means it's no good for MPEG encoders. The next 16MOD values are 704 and 720. So far I know MiniDV is 704 (some camcorders fill however the missing 16 pixels with black) while the DVD allows both (720 seems to be more present).

The difference in PAR is negligible between 704 and 720. Important is not to change inutilly the PAR/DAR, the rest is pure philosophy.PAL analogue is 702 and a bit x 575, but 704x576 is an exactly equivalent PAR+DAR.

DV is always 720, and not always (or even mostly) with black borders.

Cheers,
David.

[Jeremy Duncan]

PAL analogue is 702 and a bit x 575, but 704x576 is an exactly equivalent PAR+DAR.


You mean pal interlaced when you mention pal analogue?
What would be the source of this analogue: tv, dvd?

And you mean 704 if it has 8 pixels on the right and left side cropped off of 720 making the 704 resolution?

[2Bdecided]

You mean pal interlaced when you mention pal analogue?
What would be the source of this analogue: tv, dvd?Any video signal correctly generated and stored in the pre-DVD era ;)

Cheers,
David.

[Ghitulescu]

PAL analogue is 702 and a bit x 575, but 704x576 is an exactly equivalent PAR+DAR.

DV is always 720, and not always (or even mostly) with black borders.

Cheers,
David.

You're right I've checked again, after 9 years my memory faded a lot.

Around 2000 I got my first MiniDV camcorder, a Sharp, that recorded 720x576 wherein the leftmost 16 pixels were black. I've asked in one of the newly created digital forums and I was told this story, I didn't care too much since that was inside the overscan anyway. Since then I never inquired the values again, because I do all my work in hardware.

[Alex_ander]

If we discuss analog, there is one value set: 711 samples per line.

Your numbers are correct for NTSC, 711 is the visible part of image line captured with the standard ITU's sample frequency 13.5 MHz (unified for PAL/NTSC) and the standard number of samples per line (720 in both cases). Vertically there are 485 active lines in analog video and those 2 numbers correspond to the standard 4:3 AR. As in case of PAL, the number of captured lines was rounded to a multiple of 16 (by cropping to 480). So in case of NTSC the standard captured image can't be 4:3 by visible part (unless cropped after capture), while 704x480 area within it represents the standard AR. If stored as 720x480, cropping 711 to 704 is not necessary (but useful for encoding).