How to convert 4/3 format to 16/9

[groovyboy]

Hi!!

I know that there is different alternatives to convert aspect ratio 4/3 to 16/9 but my question is:

If i just strech the image i will still get the same amount of pixels right? so 720X480

but if i want to crop the top and bottom to keep the natural hight of the image, i guess i will loose pixels so it would give me something like 720X360 right? and it will be zoomed in right?

So i want to know between streching and cropping will there be a big difference in quality (details) when showing on a 42" HD TV screen?

If so is there a way to mixt a bit of cropping and streching?

I use Sony Vegas pro to edit and DVD architect for authoring.

[edDV]

Hi!!

I know that there is different alternatives to convert aspect ratio 4/3 to 16/9 but my question is:

If i just strech the image i will still get the same amount of pixels right? so 720X480

The TV can probably do the stretch. They normally show 4:3 with side pillars (correct), or wide stretched or non linear stretched.

but if i want to crop the top and bottom to keep the natural hight of the image, i guess i will loose pixels so it would give me something like 720X360 right? and it will be zoomed in right?

Yes, but the TV may show it as letterbox. or with black on four sides. You need to test what works on your DVD player and TV.

If you just chop the top and bottom you will have a lot of headless people. You would need to pan and zoom to make it watchable.

i want to know between streching and cropping will there be a big difference in quality (details) when showing on a 42" HD TV screen?

Yes you will be chopping out a quarter of the pixels, zooming up and recoding.

so is there a way to mixt a bit of cropping and streching?

I use Sony Vegas pro to edit and DVD architect for authoring.

Vegas allows pan and zoom, resize and recode.

[groovyboy]

So for image quality its better to strech i guess then?

[wulf109]

DVD Rebuilder can re-encode and convert 4:3 to 16:9 at the same time. Give it try you can judge the results. Some movies will turn out better than others.

[manono]

So for image quality its better to strech i guess then?

No, for image quality it's better to leave it at 4:3.

You can get the same results by just using the zoom button on your remote control for the player or TV set. Try it and see if you like what you see.

[wulf109]

It's correct that i f your TV allows you to promote a 4:3 to 16:9 and preserve the aspect ratio you get the best results. But not all TV's allow this. My Samsung for example only allows 16:9 by stretching the image width to fill the screen resulting in everyone looking like they weigh 500lbs. My Toshiba on the other hand seems ideally suited to 16:9 conversion. It offers three 16:9 options with different AR's,it also has a menu option to move the image up and down on the screen to improve framing.

[groovyboy]

Manono!!! I know that the best thing is to keep the original 4/3 aspect ratio dont get me wrong,but that was not my question...

I was comparing pan and crop vs strech... And I got the answer now. Pan and crop = 720X360 pixels so to fill the 16/9 screen they have to show bigger so less density=less details...

Strech = still 720X480 pixels ,so you are not totally right manono,because the image quality is actually the same,the only difference is that the pixels appear to be more rectangular instead.So people and objects looking streched out.

Personally, i find it really awfull to watch a 4/3 aspect ratio with piller box on a HD TV,it doesnt look good at all it kills all the theather looking movies. But the opposite is great though. Letter box on a 4/3 aspect ratio SD TV is looking just fine and actually almost better then full screen...

So that is why i am converting my older footage taken from a mini DV camcorder to fit into a widescreen TV to make it more plaisant to watch and make it look more professional.

So basicaly the best thing i guess is to strech 18% of the image and chop 12% top and bottom and follow the center of the image to keep the main things in your video.

This way you dont cut of too much pixels and people dont look too streched

Sorry for my englishI am french!!

[edDV]

If the movie cinema cropped or stretched a projected film, I'd demand my money back. Instead they close the curtain masks for 4:3 aspect films and it looks fine.

[Khaver]

You could also do a warped stretch where the edges are stretched more than the center. Many HD TV channels do this to "update" their 4:3 content. I believe there are Virtualdub and Avisynth plugins that will do this. This avisynth script will also do it.

 
myVideo=AviSource("D:\video\43video.avi")
wi=Width(myVideo)
he=Height(myVideo)

fourthree2sixteennine(myVideo)
lanczos4resize(int(he*1.7777778),he)

Function fourthree2sixteennine ( clip c)
{ 
HH=Height(c)
W=Width(c)
WW=int(Width(c) * 0.01)
c=converttorgb(c)
left1=crop(c,0,0,WW*4,HH).lanczos4resize(int(WW*4*1.72),HH).sharpen(0.7)
left2=crop(c,(WW*4),0,WW*4,HH).lanczos4resize(int(WW*4*1.63),HH).sharpen(0.65)
left3=crop(c,(WW*8),0,WW*4,HH).lanczos4resize(int(WW*4*1.54),HH).sharpen(0.6)
left4=crop(c,(WW*12),0,WW*4,HH).lanczos4resize(int(WW*4*1.45),HH).sharpen(0.55)
left5=crop(c,(WW*16),0,WW*4,HH).lanczos4resize(int(WW*4*1.36),HH).sharpen(0.5)
left6=crop(c,(WW*20),0,WW*4,HH).lanczos4resize(int(WW*4*1.27),HH).sharpen(0.45)
left7=crop(c,(WW*24),0,WW*4,HH).lanczos4resize(int(WW*4*1.18),HH).sharpen(0.4)
left8=crop(c,(WW*28),0,WW*4,HH).lanczos4resize(int(WW*4*1.09),HH).sharpen(0.35)
mid=crop(c,(WW*32),0,WW*36,HH).sharpen(0.3)
right8=crop(c,(WW*68),0,WW*4,HH).lanczos4resize(int(WW*4*1.09),HH).sharpen(0.35)
right7=crop(c,(WW*72),0,WW*4,HH).lanczos4resize(int(WW*4*1.18),HH).sharpen(0.4)
right6=crop(c,(WW*76),0,WW*4,HH).lanczos4resize(int(WW*4*1.27),HH).sharpen(0.45)
right5=crop(c,(WW*80),0,WW*4,HH).lanczos4resize(int(WW*4*1.36),HH).sharpen(0.5)
right4=crop(c,(WW*84),0,WW*4,HH).lanczos4resize(int(WW*4*1.45),HH).sharpen(0.55)
right3=crop(c,(WW*88),0,WW*4,HH).lanczos4resize(int(WW*4*1.54),HH).sharpen(0.6)
right2=crop(c,(WW*92),0,WW*4,HH).lanczos4resize(int(WW*4*1.63),HH).sharpen(0.65)
right1=crop(c,(WW*96),0,WW*4,HH).lanczos4resize(int(WW*4*1.72),HH).sharpen(0.7)
return StackHorizontal(left1,left2,left3,left4,left5,left6,left7,left8,mid,right8,right7,right6,right5,right4,right3,right2,right1)
}

[fritzi93]

DVD Rebuilder can re-encode and convert 4:3 to 16:9 at the same time. Give it try you can judge the results. Some movies will turn out better than others.

I've done a few like that, the movie "Home Alone" for one. My plasma will not allow correct AR in anything but "postage stamp" (i.e. letterbox and pillarbox) of some old 4:3 letterbox DVDs. I'm not willing to stretch and distort the video.

DVDRB will do the job just fine, albeit you have to re-encode.

[manono]

Strech = still 720X480 pixels ,so you are not totally right manono,because the image quality is actually the same,the only difference is that the pixels appear to be more rectangular instead.So people and objects looking streched out.

Therefore the image quality is not the same. Unless you like watching short fat people. Yes, you're right in that the amount of detail is still there and no reencoding is required. But at what cost? And if you do that strech 18% of the image and chop 12% top and bottom nonsense, then you will reencode, and there goes your image quality.

Khaver shows an AviSynth script that does what it's usually possible to do on TV sets (sometimes called 'Panarama View' or some such), stretch it little in the center and a lot out at the sides. It still looks like crap, though. But there's a much easier way - through the SimpleResize filter:

WarpedResize(720,480,0.5,0)

WarpedResize is also included in the SimpleResize.dll. WarpedResize will do a non-linear
stretch/squeeze in both the horizontal and vertical dimensions. This can be useful when
you want to change the aspect ratio of a video clip and have it mostly distorted at the
top, bottom, and side edges.

This could be combined with a crop to lose part of the image and non-linearly stretch the rest. The included doc explains how to configure it. It can be found here:

http://avisynth.org/warpenterprises/

[groovyboy]

<<And if you do that strech 18% of the image and chop 12% top and bottom nonsense, then you will reencode, and there goes your image quality.>>

You dont have to reencode because you take that decision BEFORE encoding!!! But,anyways what i am tying to do is loose a minimum of details and keep a maximum of the original aspect ratio. What you guys are talking me about is lightning my curiosity because i actually never heard of that warped stretch thing.It seems to be a very good alternative for anti-pillerbox man like i am...

I really want to give it a try,but i downloded the software avisynth but dont know how the hell it work??? The is no program??? I installed it and all i get is a few script files examples but dont know how to deal with that...

[manono]

Personally, i find it really awfull to watch a 4/3 aspect ratio with piller box on a HD TV,it doesnt look good at all it kills all the theather looking movies.

It looks fine. It looks exactly how it's supposed to look - 1.33:1 at the correct aspect ratio. Anything else is foolish. And at the original 1.33:1 you don't even have to reencode.

But,anyways what i am tying to do is loose a minimum of details and keep a maximum of the original aspect ratio.

You keep the maximum of the original aspect ratio by either not reencoding or by reencoding at the OAR.

I really want to give it a try,but i downloded the software avisynth but dont know how the hell it work???

Start reading:

http://avisynth.org/mediawiki/Main_Page

[guns1inger]

. . . . . because i actually never heard of that warped stretch thing.It seems to be a very good alternative for anti-pillerbox man like i am...

Actually it is about the worst option available

[zenzen1]

Khaver
"I believe there are Virtualdub and Avisynth plugins that will do this.

What is the name of the Virtualdub plugin ??
Cannot find it in a google search.....

[jagabo]

Actually it is about the worst option available

I agree. It usually looks ok for static shots but panning shots can make you sea sick. An example from an earlier thread:
https://forum.videohelp.com/threads/286202-Converting-resolution-size?p=1731366&viewful...=1#post1731366