How to find out correct resolution in Megui?

[rudolfp]

Hi guys, im new to the encoding world and megui. I like old horror movies and i have a lot Bluray discs at home, so i wanted to encode some of them to a smaller size. So the movie im trying to encode has a resolution of 1920 x 1080 and 16:9 aspect ratio. In Megui when i want to resize to 720x... there are 4 options (mod16, mod8, mod4, mod2). By default it is set to mod8, so it gave me the resolution of 720x392 (after removing top and bottom blackbars), my question is: how can i find out the proper resolution for the video? I mean how can i know which from the 4 options is proper? When i switch from mod8 to mod16, it gives me 720x384, and mod2 gives 720x390. Any ideas?

Thanks in advance

Regards

[LigH.de]

Neither is, as far as I see: 720 : 16 * 9 = 405. The reason for this mistake is probably that you want to rescale from a square pixel format (HD video) to another square pixel format (for PC or mobile devices), but MeGUI assumes an ITU-R deskewing which would have been correct in times of analogue TV.

Before continuing ... are there any constraints your result has to fulfill? Is your target playback device equipped with a lower resolution display, so you are forced to limit the width to 720 pixels? Or do you just erroneously assume that it would be a good idea to use the same common width as on a DVD Video?

[hello_hello]

Are you using the script creator? Even if you are, it's impossible to know what the aspect ratio of the source is without knowing how much black border MeGUI cropped.

1980/1080 = 16:9 or 1.777778

If MeGUI cropped a total of 40 pixels from the top and bottom then your new resolution is 1980/1040 = 1.903846

If you picked a height of 720 then the exact width would be 720 / 1.903846 = 378.181818

The mod setting kind of determines how accurate the resizing can be. The nearest mod16 height (height divisible by 16) is 384. For mod2 (height divisible by 2) it's 378. I'd stick with mod4 for playback compatibility.

Mod4 also gives you 720x378 for my example above, but that's why the script creator displays an aspect error. You want it to be as close to zero as possible, so after MeGUI has chosen a height, disable automatic resizing and adjust the cropping manually (and/or the height) until the aspect error is very low. You might have to crop a few pixels from the sides, maybe a few extra top and bottom too, but fiddle with the cropping and aim for a very low aspect error.

For my example, if you increased both the top and bottom cropping by eight pixels each for a total of 56, you'd be resizing to 720x384 with zero aspect error. (1920/1024=1.875 and 720x384=1.875) Or, you could increase the top and bottom by a total of 6 pixels between them and resize to 720x388 for almost zero aspect error. Sometimes it's a little trial and error and you can always choose to adjust the cropping by cropping less of the black rather than cropping extra picture. Whatever you prefer.

You can also determine the new height by making the calculation shorter. Divide the original height by the original width (the remaining width and height after cropping) and multiply that by the new width for the new height. ie 1024/1920*720=384.

But let MeGUI worry about all that and check the displayed aspect error.

All the above applies to sources with square pixels. For sources where the resolution and display aspect ratio are different (such as DVDs and standard definition on Bluray) it gets a bit harder to calculate it manually, but MeGUI will still do it for you. Just aim for a low aspect error.

Edit: See post #26 for an alternative way to do it with MeGUI.

[jagabo]

720/392 is about 1.84:1 so the the movie is likely 1.85:1 DAR. Some codecs and/or players have restrictions on frame sizes requiring mod 4, 8, or 16. Some codecs are more efficient at mod8, mod16, or even mod32. And video is usually encoded as YV12 which requires even frame sizes, ie, at least mod 2. For modern players and h.264 encoding I'd stick with mod 4.

[_Al_]

Just do it with common sense, resizing or cropping. It comes here again and again but always backwords, so here it goes:

Original is 16:9, so resize to it exact 16:9 again like 960x540 or 768x432 or 640x360 whatever just exact 16:9 and THEN crop top and bottom , just black bars, not live image. Just leave some black lines there, no one even notices. Even if you do, you still get no aspect ratio error though because you resized first and then cropped.
Find Megui script to do exactly that. Or let Megui do that , even with those errors nothing happens. You could have those files all with slight AR error or not, your choice.

[jagabo]

Yeah, I don't know why people are so freaked out about small black borders and/or aspect ratio errors.

[Bernix]

Hi, I think you mean me with aspect ratio errors... I don't care about black bars, nor AR, I am watching all at 16:9 ratio with or without black bars. But it is really upsetting when you see big difference in AR (in something you really want to keep in best possible quality) that shouldn't be here.
Just here are two samples of differences between 1,85:1 and 16:9 and 4:3 and 16:9. Note that first is very small hardly noticeable in real life video.

[Attachment 43726 - Click to enlarge]

[Attachment 43727 - Click to enlarge]

Bernix

[hello_hello]

Just do it with common sense, resizing or cropping. It comes here again and again but always backwords, so here it goes:

Original is 16:9, so resize to it exact 16:9 again like 960x540 or 768x432 or 640x360 whatever just exact 16:9 and THEN crop top and bottom , just black bars, not live image. Just leave some black lines there, no one even notices. Even if you do, you still get no aspect ratio error though because you resized first and then cropped.
Find Megui script to do exactly that. Or let Megui do that , even with those errors nothing happens. You could have those files all with slight AR error or not, your choice.

Yep. Here we go again. You do realise you're possibly the only person in the known universe who does it the way you do while claiming everyone else is doing it backwards?
Common sense tell you it's possible to crop and resize with virtually zero aspect error, or with zero aspect error (I offered an example in my previous post), and as I've repeated 1045 times, you can't choose the output resolution as easily if you resize first then crop. The maths is exactly the same though. You can resize 1980x1080 to 960x540 in exactly the same way you can crop it to 1980x800 and resize to 960x400. Where's the aspect error?

As you proved when you repeatedly ignored the samples I posted during the last discussion, any aspect error can be reduced to the point where it's undetectable. I think the Avisynth resizers, due to the way they resample, can introduce a small aspect error on their own anyway, even if you don't crop. On a few occasions I've compared the source to a resized version running fullscreen on my TV and noticed a few pixels of picture missing from the sides I definitely didn't crop. Try it sometime. I think you'll find you're not as aspect error free as you imagine.

[jagabo]

A 30 percent AR error is obvious to just about everyone. 4 percent may visible in some material. But the OP's 720x392 (assuming the source is really 1.85:1 and MeGui isn't otherwise correcting the scaling) is less than 1 percent. If he goes with mod 4 he'll get a 720x388 frame and only about a 1/2 percent error.

[_Al_]

hello_hello

Why would I care about your samples if mine workflow is correct? You HAVE AR error most of the time (negligible but you have).

I explained op an option, do you understand ? No AR error ever, he can do whatever he wants as you can do. Now piss off.

[Bernix]

Yeah, I don't know why people are so freaked out about small black borders and/or aspect ratio errors.

I felt it has something to do with my post, it was just 3% so less then 1,85/(16:9). thats all.
Thank you for clarification of it.

Bernix

[hello_hello]

hello_hello

Why would I care about your samples if mine workflow is correct? You HAVE AR error most of the time (negligible but you have).

For the same reason you ignored my comment about resizers producing an aspect error in my previous post, because it doesn't support your claims. And no, I DON'T have an aspect error most of the time any more, because my new script, which is just about ready for prime-time, does sub-pixel cropping. Well at least it's theoretically zero, just as it is when you're resizing the black borders you love.
Seeing as you asked though, when you're having a discussion with someone, they make points, you read them and reply, and they read yours and reply to them etc. Children discuss topic by ignoring anything that doesn't suit them. That's why you might care, if you were all grown up.
Yes, I sometimes had an aspect error so small, YOU couldn't detect it, so you pretended not to look at the samples, and YOU CAN'T crop and resize to a specific resolution most of the time as I do.

I explained op an option, do you understand ? No AR error ever, he can do whatever he wants as you can do. Now piss off.

Whoops. I upset baby Al by disagreeing with him again. No you didn't just explain an option, you explained how to use common sense and not to do it backwards as though your method was the only sensible one, like the rest of the world does it differently for no apparent reason.

[_Al_]

I lay down an option, do you understand?
This is quite retarded. You messing up yet another thread. Do you know why there is this forum? To bring answer's, options. This forum does not have a rule to follow consensus only. I give one opinion about resize. You seam to have a problem with it for no reason whatsoever, not even realizing it. I cannot wait when you start to include a Planck constant in your calculation to prove something. Missing the point that there is nothing to prove. I say there is an error, you say negligible, so let it be right there.

[_Al_]

Whoops. I upset baby Al by disagreeing with him again. No you didn't just explain an option, you explained how to use common sense and not to do it backwards as though your method was the only sensible one.

It is a common sense for me right after I gave it a though how I can write a program to automatize this without introducing an error or back control so that error is not too big. Then I realized that there is methods (megui and whatever else) that use other things to make sure. I realized it is not needed. I realized I have to resize first. That was all. I said , Jesus that's a common sense, why would no one brought it up before. Why no one is mentioning this. Do not take this freaking personally. The baby here is you, not even seeing it. So I bring this option up here.

[hello_hello]

I lay down an option, do you understand?
This is quite retarded. You messing up yet another thread. Do you know why there is this forum? To bring answer's, options. This forum does not have a rule to follow consensus only. I give one opinion about resize. You seam to have a problem with it for no reason whatsoever, not even realizing it. I cannot wait when you start to include a Planck constant in your calculation to prove something. Missing the point that there is nothing to prove. I say there is an error, you say negligible, so let it be right there.

I messed up a thread, yet you keep arguing. Self-righteous much?
My problem is the OP asked a specific question about using MeGUI to crop and resize, and here's a newsflash, you didn't even come close to answering it. MeGUI, like every other GUI on the planet, doesn't work the way you do. Do it your way. I'm happy for you. We all have different workflows. I've said that countless times, That's common sense and not backwards. Now tell the OP how to do it your way using MeGUI, because that's the question he asked.

"Start to include a Planck constant in my calculation to prove something"? Well aside from the fact that if I did, you'd ignore it and go back to repeating yourself, you're just being childish again. I've created a script. You've created a program for resizing. Wow, that sounds so different, yet apparently yours is far more clever. Your program must double as a neutrino detector.

[hello_hello]

Whoops. I upset baby Al by disagreeing with him again. No you didn't just explain an option, you explained how to use common sense and not to do it backwards as though your method was the only sensible one.

It is a common sense for me right after I gave it a though how I can write a program to automatize this without introducing an error or back control so that error is not too big. Then I realized that there is methods (megui and whatever else) that use other things to make sure. I realized it is not needed. I realized I have to resize first. That was all. I said , Jesus that's a common sense, why would no one brought it up before. Why no one is mentioning this. Do not take this freaking personally. The baby here is you, not even seeing it. So I bring this option up here.

Why do you keep asking the same question over and over while ignoring the answer over and over? You can't crop and resize to a specific resolution doing it your way and that's why every GUI on the planet is designed to do it the other way around. Common sense really.
Have you noticed the edges of your borders/picture get noticeably more fuzzy after you've resized them? I certainly have. That's another reason I crop them before resizing.

[_Al_]

I really do understand why some guys have problems in science to bring an issue up or new methods. Those older guys usually have to die out and young ones take over.

Because they just take an opinion and pull a problems out of their asses. Resizer messes up resize (so does your resize), edges are messed up (so are yours so hey I have wonderful idea cut it!). Unbelievable. You do not see those because it is on the edge. Christ sake.

I can pretty much imagine a GUI encoder/resizer that allows you to resize to the same AR, then image pops up with a slider to manually adjust and get rid of those black bars. You just set mode, or it warns you. Or there is going to be autocrop.dll that would crop that without cutting live image with chosen mode. Autocrop.dll author might do that modification if he wanted or someone else. You see nothing fancy. I do not give rats ass how guys do it now. Because I just told you, I made mine and it does automatically as I want, so the other can do it as well if they want.

[hello_hello]

I really do understand why some guys have problems in science to bring an issue up or new methods. Those older guys usually have to die out and young ones take over.

Don't hesitate to disrupt the thread again another pointless rant.

Because they just take an opinion and pull a problems out of their asses. Resizer messes up resize (so does your resize), edges are messed up (so are yours so hey I have wonderful idea cut it!). Unbelievable. You do not see those because it is on the edge. Christ sake.

As the points become lamer, highlighting is often used to compensate. When you were highlighting, did you notice everything you just said confirmed your method is no more free of problems than mine is?

I can pretty much imagine a GUI encoder/resizer that allows you to resize to the same AR, then image pops up with a slider to manually adjust and get rid of those black bars. You just set mode, or it warns you. Or there is going to be autocrop.dll that would crop that without cutting live image with chosen mode. Autocrop.dll author might do that modification if he wanted or someone else. You see nothing fancy. I do not give rats ass how guys do it now. Because I just told you, I made mine and it does automatically as I want, so the other can do it as well if they want.

You should explain to the OP how to use your imaginary GUI. And while you're at it, explain how to take a 1920x1080 image, resize it to 1280x720, crop a few pixels from the top and bottom, and still have a 16:9 image. Is that how it'd work?
How guys do it now is another thing you don't give a rats arse about is it, along with answering the question the OP asked?

[_Al_]

You can't crop and resize to a specific resolution doing it your way

op does not know what he wants, he needs to make it smaller.
Like most questions they do not know.
So he says hey, I need to resize to 720. I told him a rule. It needs to be 16:9. 720 cannot do it. He just made it up. So does that mean , lets jam the bucket and do it. We should be first to tell him, not 720, forget that number it is not year 1990. If he wants 720 (note, he does not, no reason) then MeGUi can pull its calculating spree and come up with a number depending on a mode. I do not dispute that. You seam to have some comprehensive disorder, I gave a solution for HIM, not MeGui. It's is not 1990 anymore to insist on it. Move on.

[_Al_]

Anyway go to hell, will you, I'm done. It's ridiculous.

[hello_hello]

A 30 percent AR error is obvious to just about everyone. 4 percent may visible in some material. But the OP's 720x392 (assuming the source is really 1.85:1 and MeGui isn't otherwise correcting the scaling) is less than 1 percent. If he goes with mod 4 he'll get a 720x388 frame and only about a 1/2 percent error.

Al's fabulous resize first, crop second method, also completely ignores the fact that his cropped image has to be upscaled to whole pixel dimensions on playback. That's probably just as likely to introduce as much or more distortion as I do when cropping an image and resizing it with less than 0.1% aspect error.

Edit. Oh dear. Baby Al appears to have spat out his dummy again.

[hello_hello]

You can't crop and resize to a specific resolution doing it your way

op does not know what he wants, he needs to make it smaller.
Like most questions they do not know.
So he says hey, I need to resize to 720. I told him a rule. It needs to be 16:9. 720 cannot do it. He just made it up. So does that mean , lets jam the bucket and do it. We should be first to tell him, not 720, forget that number it is not year 1990. If he wants 720 (note, he does not, no reason) then MeGUi can pull its calculating spree and come up with a number depending on a mode. I do not dispute that. You seam to have some comprehensive disorder, I gave a solution for HIM, not MeGui. It's is not 1990 anymore to insist on it. Move on.

I've moved on from 1990. I'm adding Plank constants to my scripts and doing sub-pixel cropping for zero aspect error, while you're resizing everything, cropping the fuzzy black borders you created and living with the remaining aspect ratio. It sounds more like something you'd have done while running Windows 3.1 than you'd do today on Windows 10. Modern computers are pretty fast at calculating that sort of thing. Have you considered making better use of your PC?

[_Al_]

also completely ignores the fact that his cropped image has to be upscaled to whole pixel dimensions on playback. That's probably just as likely to introduce as much or more distortion as I do when cropping an image and resizing it with less than 0.1% aspect error.

Edit. Oh dear. Baby Al appears to have spat out his dummy again.

Another pissant argument, that relates to you as well. So in your World it makes my resize wrong. Wonderful. Except your mistake could be added, mine is created. But I guess my negligible error is a bastard as oppose your error. And if someone works with that copy it is still 1:1, so further error might not be introduced. If you insist on pissant argumentations.

[hello_hello]

also completely ignores the fact that his cropped image has to be upscaled to whole pixel dimensions on playback. That's probably just as likely to introduce as much or more distortion as I do when cropping an image and resizing it with less than 0.1% aspect error.

Edit. Oh dear. Baby Al appears to have spat out his dummy again.

Another pissant argument, that relates to you as well. So in your World it makes my resize wrong. Wonderful. Except your mistake could be added, mine is created. But I guess my negligible error is a bastard as oppose your error. And if someone works with that copy it is still 1:1, so further error might not be introduced. If you insist on pissant argumentations.

If I crop an image and resize to 16:9 with 0.1% error, that's it. I can upscale to 1080p on playback without introducing any further error. That's the basis of your entire argument.
When you resize to 16:9 first and then crop a few pixels, how much aspect error is introduced when upscaling to 1080p on playback? Often it'd be more than 0.1%, I'd guess. Sometimes a negligible aspect error is unavoidable and you can't have it both ways. Either it matters or it doesn't. It's not a pissant argument, it's simply not living in denial.
And you still haven't explained how you'd resize a 16:9 image down (as the OP is doing) to 16:9 dimensions, crop a few lines of black, and still end up with 16:9. As soon as I know how to do that, I'll switch methods.

[_Al_]

If I crop an image and resize to 16:9 with 0.1% error, that's it. I can upscale to 1080p on playback without introducing any further error. That's the basis of your entire argument so you can't deny it.
When you resize to 16:9 first and then crop a few pixels, how much aspect error is introduced when resizing to 1080p? More than 0.1%, I'd guess. Sometimes a small aspect error is unavoidable. You're not using an aspect error free method and you can't have it both ways. Either a negligible aspect error matters or it doesn't. When you've made up your mind.....
And you still haven't explained how you'd resize a 16:9 image down (as the OP is doing) to 16:9 dimensions, crop a few lines of black, and still end up with 16:9. As soon as I know how to do that, I'll switch methods.

I know you are a douchbag, but that above says you are a moron, that changes the whole thing, also you are the only one talking about 16:9 delivery here. Adios.

[hello_hello]

I know you are a douchbag, but that above says you are a moron, that changes the whole thing, also you are the only one talking about 16:9 delivery here. Adios..

How many times are you planning on leaving? You've already had more farewell posts than Barbra Streisand had farewell tours.
16:9 was just an example. Pick your favourite aspect ratio and tell me how you resize first, then crop to always achieve it, because for related episodes of a TV show, many people like to crop and resize them to the same aspect ratio.
16:9 is just the aspect ratio you might be most likely to aim for, because many sources are very close to 16:9 after cropping, and you may have noticed, that's also your TV's aspect ratio.
Anyway, I can wait until you're done with pathetic, childish name calling and you've stopped crying long enough to explain how you do it.

Oh.... and you're the only one talking about resizing first and then cropping. The rest of us were talking about how to crop and resize using MeGUI, as per the OP's question.

[hello_hello]

Giwen Al has spat the dummy and won't answer a simple question after making a mess of the thread, for completeness I'll explain how to do it backwards using MeGUI (resizing first and cropping second). No need to write your own special program.

- Open your source video using MeGUI's Script Creator. You can add filtering such as de-interlacing or noise removal if need be, but disable cropping.

- Resize to exact 16:9 dimensions. The closest width to 720 that gives you exactly 16:9 is 704, so you'd resize to 704x396. It's mod4. If you want a slightly higher resolution, try 832x468. It's still exactly 16:9. I use both those resolutions regularly for standard definition 16:9. I generally use Spline36Resize.

- Save the script, but don't load it for encoding.

- If the Script Creator closed, open it a second time from the Tools menu. This time, instead of using the source video as the input for the Script Creator, use the script you just saved. Your source will now be 704x396 or 832x468 etc, at least as far as the Script Creator is concerned.

- Disable the script creator's resizing if need be and apply any cropping required to remove the black, keeping it mod4. The remaining picture will be the remaining picture aspect ratio without any aspect error, whatever that turns out to be.

- Save the second script and encode it.

Personally I prefer to crop first and control the output aspect ratio, even if there's an aspect ratio so small it's not detectable, but if you're Al and can only accept one way of doing things, that's how you do it his way using MeGUI.

[_Al_]

OMG that is what I told you, using Avisynth script, you bring this up now? Instead of yapping you should post it right away and we did not have to argue, I'd correct you then and we'd go home.

But you actually omitted how to do it properly
and
there is actually a visual feedback for cropping changing so anyone can crop as pleases, yes that feature that you were mocking as a non existent actually exist right underneath your own arse

so as he put it, Tools/avs file creatore/ dgindex (I chosed), then go into queue to start indexing. Then actual avs script creator pops up.


Then it should be done rather this way:
firstly, in that AVS script creator window, one better to change default "avs script profile" pressing CONFIG button for right order, or make a new profile:
<input>
<resize>
<crop>
you can delete everything if not denoising and just paste in that above, note resize is above cropping, save it

Then back in avs script creator window, you change crop, you do not know what values, you can enter some values like cutting 10 from top and bottom. Then select resize (yes nice exact 16:9) , then check preview window for intimidate graphic image feedback pressing "PREVIEW Avs Script button"

Then just correct crop as you please, and again press that "PREVIEW Avs Script button", do it , correct it as many times needed, after that Save it.

Go to the queue and encode.

[_Al_]

Personally I prefer to crop first and control the output aspect ratio, even if there's an aspect ratio so small it's not detectable, but if you're Al and can only accept one way of doing things, that's how you do it his way using MeGUI.

I do not dismiss whatever you or Megui or other do, I suggested other option and you torpedo it like it is Russian invasion.

With proper DVD, BD or UHD sources it is more that ok to do. I do not talk about some other stuff that you like to bring up, video that was in some way more or less manually messed up before.

[hello_hello]

But you actually omitted how to do it properly
and
there is actually a visual feedback for cropping changing so anyone can crop as pleases, yes that feature that you were mocking as a non existent actually exist right underneath your own arse

Personally, I'd recommend you omit the personal insults when trying to prove you know better, because you're once again blaming someone else for your own behaviour.
Forgetting for the moment you're at least partly wrong, maybe if you'd been all grown up when you started posting here and explained how to do it, you'd have saved a lot of arguing.

so as he put it, Tools/avs file creatore/ dgindex (I chosed), then go into queue to start indexing. Then actual avs script creator pops up.

Then it should be done rather this way:
firstly, in that AVS script creator window, one better to change default "avs script profile" pressing CONFIG button for right order, or make a new profile:
<input>
<resize>
<crop>
you can delete everything if not denoising and just paste in that above, note resize is above cropping, save it

Then back in avs script creator window, you change crop, you do not know what values, you can enter some values like cutting 10 from top and bottom. Then select resize (yes nice exact 16:9) , then check preview window for intimidate graphic image feedback pressing "PREVIEW Avs Script button"

Then just correct crop as you please, and again press that "PREVIEW Avs Script button", do it , correct it as many times needed, after that Save it.

Go to the queue and encode.

I've used MeGUI for many years so I know it quite well. The problem is, MeGUI always bases it's resizing on the cropped input, even if you swap the order of cropping and resizing. It's something anyone who's cropped and resized before should notice.

Admittedly you can do it exactly how you described, but next time you explain it, be sure to emphasise that if you change the cropping/resizing order, MeGUI's aspect error calculations will be wrong unless you calculate a new Input DAR yourself and change it. Or you could manually add the cropping to the script rather than use the GUI, or you could even cut and paste the cropping MeGUI adds in order to move it below the resizing, and yes and you can preview the result, but how would MeGUI factor that into it's aspect ratio calculations?

A newbie probably wouldn't know to ignore the aspect error though. That's why I suggested doing it in two steps. First you resize, then save the script and use it as the basis for creating a new one, and when you open it, MeGUI will base it's calculations on the script's display aspect ratio and show the correct aspect error. You could even use the anamorphic option, make note of the aspect ratio MeGUI adds to the top of the first script, and set that as the Input DAR after loading it as the video input for the second script.

Check out the following screenshots. If you've gone through the process yourself I'm astounded you didn't notice what was right under your arse. I've resized first myself and then cropped on occasion, if was warranted for some reason, but you need to know to ignore the aspect error MeGUI displays and do any necessary calculations yourself. The OP did ask how to determine the correct resolution in MeGUI though, not how to get it to display the wrong one.