Aspect ratio, cropping, letterbox... AAARGGH!! Help please!

cadmus · Post by **cadmus** » Fri Mar 24, 2006 1:27 pm

I'm really hoping someone can help me out here please!! I'm having a problem with the left and right edges of my video being chopped when rendering to DVD Mpeg, and my head is now spinning in trying to work out aspect ratios and where it all sits.

I'm using MiniDV PAL source video, which is 720x576, or 1.25:1. I'm creating DVD PAL files, and putting them to 4:3, as I believed was what I needed to do (standard). However, 4:3 = 1.33333:1, which is a lot different to 1.25:1, which I think explains why my left and right edges are being chopped.

I have used some images, and thoght I was doing the right thing by making these 720x576, but they seem to show the problem worse than the video... ;-(

It's really quite annoying, and I need to rectify it so that I show the entire video. Letterbox would be fine. How can I do this?

I thought initially that it was an "overscan" issue, and that I just had to "lump it" on my old CRT TV. But as I now have a plasma (852x480 = 1.775:1 - more crazy numbers!!), and it is exactly the same "cropping" of the L&R edges on it, I don't think it is now.

I would think this would be a very common problem, and even more so for NTSC, as at 720x480 it is 1.5:1, which is even further out...

Am I missing something? Or is my understanding completely flawed? Or both??

Any help would be greatly appreciated thanks guys. I'm going nuts!!!

Downstairs Video · Post by **Downstairs Video** » Sat Mar 25, 2006 3:19 am

Hi cadmus,

Welcome to the world of video editing.

Lets keep it simple.
Firstly, in pal you are correct, 720x576 is the standard for 4:3

You talk about letterbox, I will come to that soon (more numbers - sorry)

The problem you are facing with the cropping on the left and right is actually a problem with the monitor or TV, ALL do it to some degree.

TV picture tubes are not all that acurate, when I did some tests in the early stages of learning, and running into all your problems causing me much grief, I did a controlled test.

If you copy your work back to a video camera, you will get some cropping, then if you copy it to a VHS tape, you will get more cropping, and then if you watch it on TV, the TV will crop it again. Therefore you are not the one at fault.

Now to the solutions.
Firstly, your edited production to DVD will have a lot less cropping when watched back on an LCD screen than a TV. But you need to allow for this cropping. That is why in MSP when you go to make a title clip it shows you the rectangle, safety margin, that you need to stay inside when creating text so your text doesn't get cropped later.

Most people aware of this problem, both film their video and create their slides to allow for the cropping effect.

"Oh dear! I have produced my video and slides without allowing for the cropping" -
SOLUTION
I found a simple work around is to make a template with a moving path, 'picture in picture'
I have found that the left and bottom is a little more cropped than the top and right.
Therefore, try making a "picture in picture" with the Width at 650, Height at 520, X at 368 and Y at 283
Then, drop the template on all the effected video and slides, and by the time you play it on your TV - hey presto it looks right.

Now to letterboxing - This is different again. This is to create wide screen on 4:3 Another words, when you watch it on a 4:3 TV it has a black strip at the top and bottom. If you would like to know more about wide screen (16:9) both letterboxing or non leterboxing let me know, but be warned - more numbers.

I hope this helps a little, give it a go and let me know the results.

cadmus · Post by **cadmus** » Sat Mar 25, 2006 10:25 am

Thanks for taking the time to help out, Downstairs. I feel stupid as I've been doing this off and on for probably 5 years now, but I've only really just sat down and done the math to work out where my problem might lie!

My impetus for revisiting this problem was watching my latest work on my newly-acquired plasma TV (yee-hah!!). I found that it was virtually IDENTICAL cropping of the left and right to a normal old CRT TV, which was not what I expected at all.

I know about the title-safe margin box, and use it, so my MSP8 titles work great. For this production though (I'm doing commercial DVD's of local Kickboxing shows) I decided to change the titles to use a Photoshop image (720x576) for the fighter details instead of using MSP8 titles, which now might have been a mistake! I had a problem with the image not going to the edges in my preview window, which I think was from not ticking the "Keep aspect ratio with moving path" box, but it was perhaps the right way to go with it not ticked - it might at least look correct when displayed on a TV that way!

In previous DVD's I have rendered out the video to MPEG, and then re-rendered after applying a moving path to it at 660x528 (keep aspect ratio - X360,Y288)), much like you suggested, except your idea is a lot smarter! Obviously my old way was not ideal, as I lose quality by re-rendering it, so I was hoping for another way around it I wasn't aware of (that didn't involve the moving path). I've avoided using the moving path on the files within the editor simply because I think of it too near the end, and by then I have about 20-30 different video clips in 12-15 fights to add the moving path to, but now I think about it that's ridiculous - it's hardly any harder to add it to 30 than it is to 1!! So I'm going to do it now over the ones I'm still working on, and redo it over the ones I've already done. It really isn't going to add too much time - and may even help the eventual file sizes, which will allow me to increase quality!

The "left and bottom" thing is interesting - I've previously only done it from the centre, assuming uniformity. I'll have a go your way and see what it does for me.

When you say template though, are you just meaning a custom Moving Path based on a PIP? If so, that's what I've done, but if not, how? I've got a video filter applied to each project as standard, but didn't think there was a way to apply a moving path across every file in the project.

It still seems strange that this is such a problem. Why haven't the new standards for TV's (LCD/plasma) and video camera standards met???????

Again, thanks for your time and help. I'll let you know how I went. Cheers!!

Downstairs Video · Post by **Downstairs Video** » Sun Mar 26, 2006 5:11 am

(When you say template though, are you just meaning a custom Moving Path based on a PIP? If so, that's what I've done, but if not, how? I've got a video filter applied to each project as standard, but didn't think there was a way to apply a moving path across every file in the project. )

Yes moving path is what I meant.

(It still seems strange that this is such a problem. Why haven't the new standards for TV's (LCD/plasma) and video camera standards met??????? )

I live in a more rural area of Australia (Tasmania) And one of the TV stations (yes we have more than one

) Never gets it correct on their own braodcasts, sometimes cropped at the top, sometimes on the right, sometimes both. It drives me nuts that pros get it sooooo wrong!
So if pros struggle ...... We are allowed to as well!

cadmus · Post by **cadmus** » Sun Mar 26, 2006 5:32 am

To be fair, the "pros" working at the local station near you probably dont even meet your/our standard! I have to say too, that being from Tasmania would have to give you guys an unfair advantage with video editing - dual monitor work would be easy with your two heads!!

:shock:

Anyway, thanks for your help, and for making me feel slightly less stupid. The only way to repay you for your time and help would have to be by making old Tasmanian jokes at your expense, wouldn't it?