Edges cut off of DVD when viewing on TV.

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Level 1

19 points

Edges cut off of DVD when viewing on TV.

I created a simple iDVD project and imported a video file (both .avi file and an iMovie project file). After burning the DVD and playing it on my DVD player, I noticed that a little bit of the edges of the video were being cut off (top, bottom, left and right sides). So I played the DVD on my eMac, and I was right, a small amount had been cut off when viewing on the TV. I played the DVD in several other DVD players of family and friends and as far as I can tell the same amount is getting cut off on all players. Does anyone know why this is?

I found online a plug-in for iMovie that allows me to "shrink" the video, basically adding small black bars along the outer edge of the video. This works fine, but it takes forever to "shrink" a 20 minute video (about 8 hours) and also when viewing the DVD on the computer, you see these black bars. If any one knows any easier solutions please let me know. Thanks.

Posted on Nov 2, 2005 12:50 PM

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Answer 1

Old Toad

Level 10

215,640 points

Nov 2, 2005 1:08 PM in response to Eric Rook

I found a way to do it with Quicktime Pro and an Apple script. It's a little more work than the iMovie plugin but takes much less time, maybe an hour the first time. Here's how:

Masking Movies to the TV Safe Area for iDVD
The mask should be 640 x 480 pixels and the movie 514 x 386 (I arrived at this figure by making a snapshot of the TV save area of an iDVD project with Snapz). You can set this size after youve joined it with the mask movie with Quicktime Player Pro.
Import the black mask jpg file into iMovie and and export it as a .mov file at the same length as your movie (there may be a way to not have to create a specific length mask for each movie but I haven't found it. If the times do not match the movie file will be synced to the length of the mask movie).
Open the mask movie in QT Player Pro and then open your regular movie and make it the front window of the two. Now you'll need to run a QT Player AppleScript titled "Merge Movie 1 into Movie 2". You can get it from this Apple site: Quicktime Player Scripts.
Then run the script. You can then run the merged movie to check it out. Your movie will be located in the upper lefthand corner of the window when played.
When you open the Movie Properties window from the Window menu for the combined file youll see the following:
Video Track 1: the black mask
Video Track 2 : you movie file
Tween track: Have no idea what this is.
Sound track: self explanaotry
Black mask.
To set the size of your movie to the correct size select it in the Properties window and click on Visual Settings pane. Then enter 514 in the first field and hit enter. With the Preserve Aspect Ration box checked the other size will automatically be set.
To center the video track in the center of the mask select the Video Track 2 item and plug in a offset of about: 60 & 40. You'll probably have to play with that to fine tune the centering. Doing the math and subtracting the movie dimensions from the mask dimensions and dividing by two just didn't get it perfectly centered. I'm sure I'm missing something here.
Now save as a new self contained movie after checking the High Quality box at the bottom right.
You can not import it into iDVD for preview and burning. One drawback is that you can't invoke the TV save area for a movie in iDVD to check it out. But you can mark it on the monitor screen while viewing a menu or still image slideshow and then play the movie to see how close you came.

Hope this has been of some help. Good luck.

OT

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Answer 2

F Shippey

Level 7

21,500 points

Nov 2, 2005 3:30 PM in response to Eric Rook

Eric,

The loss is due to something called "overscan". Analog TV CRT display devices need to see a video signal that includes synchronization pulses to end each line and to start a new video field. To avoid seeing this sync pulse "noise" on the display, the image sent to the display is larger that the area you actually can see (this is the "overscan"). Not all TV displays have the same amount of overscan, so we talk about two "safe" areas. Title safe is the part of the image that will be seen on ALL TV sets. Action safe is the part of the image that will be seen on MOST TV sets.

Masking the edges of you video images to make sure everything is shown on a TV screen, has the disadvantage of making the image look "ugly" when played back to a computer monitor.

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Answer 3

Eric Rook Author

Level 1

19 points

Nov 3, 2005 8:57 AM in response to Old Toad

Thanks, this should save me tons of time.

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Answer 4

Eric Rook Author

Level 1

19 points

Nov 3, 2005 9:11 AM in response to F Shippey

I created a test DVD, that had a background on the main menu with rectangles (4:3 ratio) each a different color, inside of each other. For example I started with 640x480 rectangle of one color, then a 600x450 rectangle of another color on top of that, centered, then a 540x405 rectangle of another color on top of that, centered, and so on. The object was to see just how much was getting cut off when viewing it on the TV instead of the computer. Then after creating the DVD I played it in my DVD player and discovered that when viewing on the TV you view roughly 600x450 of the 640x480 picture. That means you are losing 20 pixels from the sides, and 15 from the top and bottom. This is 12.1% of the total viewing area, doen't that seem to be a lot for overscanning?

I have not had a chance to play this test DVD on other players and TVs or to try and examine the difference with factory DVDs.

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Answer 5

F Shippey

Level 7

21,500 points

Nov 3, 2005 9:27 AM in response to Eric Rook

This is 12.1% of the total viewing area, doen't that seem to be a lot for overscanning?

Overscan varies from TV set to TV set - that's why we talk about Title Safe and Action Safe areas.

I have not had a chance to play this test DVD on other players and TVs or to try and examine the difference with factory DVDs.

Only the TV set has any affect on overscan.

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Answer 6

Eric Rook Author

Level 1

19 points

Nov 3, 2005 10:01 AM in response to F Shippey

Is this reasonable to lose that much of the viewing area from overscan? I guess it's just hard for me to believe that that much is getting cut of on my TV. I'll try the DVD on some friends' TVs and see if its any better or the same.

I guess I'm stuck losing 12% or having it look crappy on the computer.

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Answer 7

F Shippey

Level 7

21,500 points

Nov 3, 2005 10:24 AM in response to Eric Rook

I guess it's just hard for me to believe that that much is getting cut of on my TV.

That's because they consider the title safe and action safe areas when they shoot content for TV - they know you won't see the entire image that is transmitted, so they don't put important content around the edges.

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Answer 8

Eric Rook Author

Level 1

19 points

Nov 3, 2005 10:25 AM in response to F Shippey

Do you know how overscan is calculated? This is how I arrived at 12%:

640x480=307200 (total pixels)
600x450=270000 (total pixels viewed)
307200-270000=37200 (pixels not viewed)
37200/307200=.121*100 = 12.1 (percent of pixels not viewed)

According to the following page (about 1/3 down the page in the Geekbox table), my TV should have an overscan of 5%

http://reviews.cnet.com/SonyKV_32HS420/4514-64817-30895536.html

Thanks.

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Answer 9

F Shippey

Level 7

21,500 points

Nov 3, 2005 10:35 AM in response to Eric Rook

http://scanline.ca/overscan/ is an excellent overview of overscan

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Answer 10

F Shippey

Level 7

21,500 points

Nov 3, 2005 10:46 AM in response to Eric Rook

I guess I'm stuck losing 12% or having it look crappy on the computer.

BTW, one approach some people use is to put the movie on a DVD in two different sizes - one for TV viewing and one for computer viewing.

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Answer 11

Eric Rook Author

Level 1

19 points

Nov 3, 2005 10:56 AM in response to F Shippey

Thanks, this was very helpful.

Also, putting 2 versions of the movie on the DVD I think would be overkill. I think I'll just have to live with overscan.

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