My 640 x 480 video is clipped (cropped) on TV sets

ingvarai wrote on 5/18/2008, 5:20 PM
Hi,
I have made my very first compiled video, recorded using a mobile phone and edited using Vegas. And I make a DVD setup using DVD Architect.

It looks magnificent on my PC. And it looks great on the 4 different TV sets I have tested it on, old CRTs and new widescreen LCDs. With one exception - it is clipped (cropped), information gets lost on both the sides and on the top/bottom.

In this regard, I have two questions:

- How can I preview this clipping on my PC monitor, so that I, if possible, can tweak Vegas and/or DVD Architect to avoid this? The preview function in DVDA seems not to be able to do this, without using a PC card and an external TV monitor.

- How can I render my video to avoid clipping? I believe this clipping is called "letter boxing".

Ingvar

Comments

farss wrote on 5/18/2008, 5:33 PM
You should always assume that part of what you shoot with any camera will be clipped and make allowance for it. Good cameras have options to turn on a range of Safe Area Generators so you can see what might get lost when you're shooting. At the same time never assume that anything will be cropped either.

Of course none of this will be available in a mobile phone camera so you might either have to just guesstimate or draw some marks on the screen. Just how much to allow is a difficult question, different TVs crop different amount of the picture, 10% is normally pretty safe.

In Vegas Preview window you can turn on a two safe area generators as you can in DVDA. By default they're at 10% and 15%. They provide Action Safe and Title Safe areas but again they are adjustable and there's no hard rules regarding where they ahould be set although the defaults will probably serve you OK.

And no, your problem as you've described it is not letterboxing. Letterboxing occurs when a 16:9 image is fitted into a 4:3 image leaving black bars at the top and bottom.

Bob.
Terry Esslinger wrote on 5/18/2008, 5:34 PM
Its not letterboxed unless you have black areas surrounding the video or at least on the top and bottom. It sounds more like you are experiencing over/underscan. This is not an occurance on a PC monitor but EVERY TV set has some degree or other. The problem is that different tvs have different amounts. Its a PIA. However in the Vegas preview window you should see two sets of dotted lines encircling the window. The outer one is the Scan safe area. Supposedly nif you keep your video within that area you should avoid scan problems with the majority of tv sets. However this area is adjustable (I believe in the preferences) so it can be changed and be either better or worse. BTW the inner one is the Title safe area and you should keep all titling within that boundary.
johnmeyer wrote on 5/18/2008, 10:25 PM
You might find this article on the Artbeats site useful:

Pixel Aspect Ratio, Part 1, Fitting rectangular pixels into square holes

Here's another useful reference:

A Quick Guide to Digital Video Resolution and Aspect Ratio Conversions

And finally this one:

Determining Aspect Ratios and Resolutions

Ultimately, pretty much any time you change formats -- in this case from 640x480 square pixel to 720x480 at 0.9091 pixel aspect ratio (PAR) -- you will end up with some letterboxing. If you don't have letterboxing, then you will end up with a stretched or squashed picture. Some people insists on filling the screen, even if the video becomes distorted, but that really isn't the "right" way to display video.

Vegas usually does the correct thing, as long as you set the project properties to equal the way you are going to render the result. Once in awhile, Vegas will not correctly read the video header. You can right click on the video on the timeline and select Properties. Check to make sure that all the video properties are correct, especially the PAR.

P.S. You can download and run GSpot, drop your video onto it, and then use the "Resizing" buttons to get advice on how to re-size to 720x480 (or some other resolution).

rmack350 wrote on 5/18/2008, 11:09 PM
The term I usually hear for black on the sides is pillarboxing.

Rob
ingvarai wrote on 5/19/2008, 9:18 AM
Thanks to everybody for great help!
I have learnt that this is not quote as simple as I had imagined.
To farss, I see what I want on my PC, so the mere recording was successful. The challenge is to get as much as possible from what I see on my PC to be displayed on TV sets.
And again thanks to johnmeyer, very interesting links you have posted. What I really need now is a software based TV simulator..

Here is another interesting link:
http://www.jeremymoore.com/AdobePremiere/PAR_Displays/

Ingvar
rmack350 wrote on 5/19/2008, 11:19 AM
One of the takeaway's from John's middle link is that you shouldn't expect a 640 by 480 image to fill an SD projects frame on the left and right edges. I'm not sure why it looked okay but it actually shouldn't have. For Vegas (and this is particular to Vegas) the movie from your cell phone would have needed to be 654x480 (at least in an NTSC project)

There are ways you could compensate, by putting the media onto the timeline and then adjusting it to fill the frame, but you'd have had to either know this ahead of time or be able to see that there was a problem.

Rob Mack
Terry Esslinger wrote on 5/19/2008, 1:55 PM
What I really need now is a software based TV simulator

But it wouldn't do you much good! The under/overscan thing is different for each television set. One set may overscan 2% while another set may overscan 8% etc. Thats why the scan safe areas are there. Thats also one of the reason many people use a tv monitor hooked to their computer to get an idea of hat they are going to lose (at least with that particular set). You either shoot with the out edges of your frame containing disposable material or you pan/crop to bring the edges in and risk having some pillerboxing on sets that don't overscan as much as others. In my mind the former is preferable.
John_Cline wrote on 5/19/2008, 2:59 PM
An experienced shooter would have been aware of the overscan properties of television sets and would have framed their shots a little "looser" so that nothing of any importance was anywhere near the edges of the image. Now that you are aware of this, you have gained that experience. In the future, you will frame a little looser, too. The cropping can't be avoided, but you can compensate for it when shooting. Video shooters have been doing this for over 50 years.

In Vegas, turn on the "Safe Areas" by clicking on the cross-hatch button at the top of the preview window. The larger, outside box is called "Safe Action" and anything between this box and the edge of the preview window may (and very likely will) be lost when viewing your project on a television. The size of this overscan area will vary from television to television. Just make sure when you are shooting that nothing of any importance falls outside of the "Safe Action" box. The smaller, inside box is called "Safe Title", any text must be placed inside this box in order to absolutely guarantee that it will be fully visible on all televisions. Get a feel for where those boxes are and, in the future, frame your shots accordingly.

A lot of people are initially tempted to make the image smaller and add some black to the top, bottom and sides of the video to make the entire image visible on a TV. The problem is that all TVs overscan to different degrees and how much should you zoom in? The answer is, you probably shouldn't. I realize that this doesn't solve your current problem with the footage you have already shot, but is there really anything that important going on at the edges of the image?

If your video will only be viewed on a computer monitor and never be viewed on a TV, then you can ignore the safe action and safe title areas.
ingvarai wrote on 5/20/2008, 2:27 AM
I believe, and please correct me if I am wrong, that the ultimate goal is an identical image in the camera and on the monitor. I also believe that digitalizing video, with digital monitors, is already moving in this direction. Now, isn’t it already a certain video format which, played back on the latest digital monitors, that just skips this “ancient analog compensations” and plays back what it is fed, pixel by pixel, on a 1:1 basis? I think I recently read something about this. It was about a Hitachi (or Sony) camera, and I think it was something called a “true” 16:9 format.

I will soon drop my mobile phone camera :-) and get a real video camera, and want to leap frog over all previous stages and right to the latest technology.

Ingvar
John_Cline wrote on 5/20/2008, 3:04 AM
"I will soon drop my mobile phone camera :-) and get a real video camera, and want to leap frog over all previous stages and right to the latest technology."

I wish you the best of luck with that.
farss wrote on 5/20/2008, 3:55 AM
I believe, and please correct me if I am wrong,

Sorry to blunt but I've read what you believe several times and can't find a thing you've got right.

Suggestion. Do a LOT of reading before you leap frog or some less than honest salesman could take you for quite a ride.

Bob.
ingvarai wrote on 5/24/2008, 11:51 AM
Here is what I have done with this:
First I tried all kinds of settings, especially aspect ratios, but never got it the way I wanted it. I had a test video with vertical and horizontal numbers, to see exactly what I missed from the original footage.

I then ended up with this approach:
Being a total beginner in this field, I had misunderstood the format of my original footages. So using GSpot I found out it is 720 x 540, and I set my project's properties accordingly.

Then I rendered my Vegas project to a WMV file, all options set to best possible quality, and the format the same as my footages, 720 x 540.
The new file was loaded into a new project.
This file again was rendered to yet another WMV file, using these settings in the Event Pan/Crop editor:

Cropping 720x540 for TV

Note that "Maintain aspect ratio" is No, otherwise it won't work.
This file was used in my DVD Architect project, and lo and behold, it looks just great on the TV sets I have tried it on so far, almost no clipping, and no letterbox seen so far.

Note: I live in Norway, so it is PAL here.
I hope this infornation will be useful to someone, I like to share it with you.

Ingvar
johnmeyer wrote on 5/24/2008, 12:30 PM
I don't think you should have to do that pan/crop resize. Every time you do that, you lose quality.

In looking at your numbers, PAL DV is 720x576:

720/576 = 1.250

Now, the resizing in your pan/crop is 785.3 x 565.9. This is a ratio of:

785.3/565.9 = 1.388

What I think is happening is that you are rendering using a WMV template that uses square pixels, whereas PAL DV uses non-square pixels and has a pixel aspect ratio of 1.0926. If you take 1.388 and divide by 1.250 you get:

1.388/1.250 = 1.11

This is basically the 1.0926. In fact, I bet if you take set your pan crop height to exactly the PAL height of 576, and then multiply the PAL width by the PAL pixel aspect ratio in order to get the square pixel aspect ratio, you will probably get even closer to a perfect render (i.e., with no borders). This would be 720 x 1.0926 = 786.7 (rather than the 785.3 that you created via trial and error).

Thus, while I don't understand your workflow and therefore don't understand why you render to WMV (rather than AVI) for something that you are later going to import back onto the timeline, nonetheless, if that is what you want to do, then you should click on the Custom button in the Render As dialog and then after you have all your settings, change your pixel aspect ratio to whatever is needed to get back to the original aspect ratio, when measured in square pixels.
ingvarai wrote on 5/24/2008, 4:10 PM
John,
I realize it was a mistake to use WMV instead of AVI. I made some tests, and did not really see any difference though. And I also realize that resizing the way I do means that I lose quality.
However, it was the only way I could get a decent output on my TV, with no clipping.

I am still a bit confused about all the various topics to consider, but I am learning..
Now - how would you tackle this, in a better way than I did? I admit I do not fully understand everything you say, so please excuse me if I have overlooked something:

At one end, I have my timeline in Vegas filled up with various tracks, partly overlapping, with FX effects, sound and images. The project's property is 720 x 540 pixels, square (multi media format).

At the other end, I have DVD Architect, for which I will generate a file it can use to burn a DVD that I can play back on PAL TVs, with as little clipping og the original material as possible.

What I have done is described in my previous post. So, can I hop over the intermediate step I used, and render a file directly DVDA can use, and avoid clipping? I tried MPEG1 and came close by varying the pixel aspect ratio, but not close enough to make me satisfied.

Ingvar
Chienworks wrote on 5/24/2008, 4:27 PM
You should be using a project template that matches the output as closely as possible. Since you want to play this on PAL TVs you should use PAL DV, which is 720x576 at 1.0926PAR, but don't worry about any of those details. Just choose that project template. Drop your video on the timeline. Vegas will fit your video in the frame the best it possibly can. If your video isn't exactly the same shape then Vegas will leave some black space either on the sides (if your video is too narrow, which 640x480 is) or on the top and bottom (if your video is too wide).

If you want your video to fill the frame you have two options. 1) You can go into Pan/Crop, right-mouse-button click and choose "match output aspect". This will crop your video to match the shape of the output and fill the screen, but you'll lose some of the video. Or 2) instead of cropping, in Pan/Crop turn of 'maintain aspect ratio' on the left side of the window. This will stretch your video to fit the frame. It will distort it slightly, but you won't lose any of it.

To make a DVD rnder to MPEG2 for the video and AC3 or WAV for the audio. These are the only official formats for a DVD.
ingvarai wrote on 5/25/2008, 4:29 AM
Chienworks,

I will start a new thread regarding project templates etc.
But in general, I thought that the project should use a template in accordance with the media recorded, not the target I want to publish to. What if I want to publish my project to various targets? DVD, PAL TV, NTSC TV, YouTube.. and so on.

Ingvar
rs170a wrote on 5/25/2008, 4:45 AM
But in general, I thought that the project should use a template in accordance with the media recorded, not the target I want to publish to.

Set your project properties to the target you want to publish to - and, in the case of multiple output targets, always go with the highest quality target.
You can always change render settings later to accommodate things such as YouTube or other web-based formats.

Mike
Chienworks wrote on 5/25/2008, 4:59 AM
Mike's right.

As far as PAL TV, NTSC TV, PAL DV, NTSC DV ... you'll find that the frame aspect ratio of all of them match closely enough that it's not worth worrying about.

The important point is to choose the most appropriate output template to begin with, then let Vegas do all the thinking for you so that you don't have to. Chances are Vegas will make much better choices about formats, conversions, and fitting images to the frame than most humans will. A lot of the problems discussed in this forum come down to people trying to do all the frame and pixel ratio math themselves and not quite understanding how it works when they could have let Vegas do it all to begin with and gotten it right effortlessly.

Another large number of problems discussed in the forum revolve around having the output cropped unexpectedly on the TV. The simplest way to deal with it is to accept it and do nothing, and remember next time around to allow extra space around the edges of the frame. If you do want to fix it so the entire frame is displayed then the process is quite simple.

- Chose the most appropriate output template, such as PAL DV. Change nothing!

- Place your media on the timeline and open up Pan/Crop. Make sure that maintain aspect ratio and size about center are both selected. Drag the cropping frame out larger to reduce the size of the image inside the frame.

That's it. You're done. Do nothing else. Of course, there's the question of how much smaller to make the image, and the correct answer is ... guess. You can't know in advance how much any particular TV will crop, so the best you can do is guess. Be prepared for the fact that if you shrink it a lot, some TVs will show a black border around the image. There's nothing you can do about that, except keep the cropping in mind when shooting the original video and allow for it.
ingvarai wrote on 5/25/2008, 5:31 AM
Place your media on the timeline and open up Pan/Crop
Hi Chienworks,
Can this be done on a project basis? I have 40-50 events in on of my projects and some already have customized Pan / Crop settings.

Ingvar
rs170a wrote on 5/25/2008, 5:38 AM
If some events already have customized Pan / Crop settings, then no, you can't do it on a project basis as these events will get messed up by being forced to match new settings.
I work with still images a lot and, as long as they're in landscape mode as opposed to portrait mode, I can run a script to have every image match the project template.
Only then do I go in and customize any images I need to for zooming and/or panning.

Mike