So, you've sat down to watch your latest entirely legal DivX downloaded from the P2P application of your choice. You're watching it from the comfort of your easy chair in front of your big telly via the TV out mode of your fancy graphics card, and all seems well.
But wait! The picture doesn't fill your 32" screen! What are those unsightly black bars doing all around the edges?
It's by design, it turns out. Televisions typically chop off the edges of the picture by a varying amount - rather than having an expensive process where the picture is calibrated to exactly fill the screen, the TV manufacturers know that all that's really important is that the whole screen is lit, so they err on the side of losing some of the image off the edges. This is known as overscan.
The graphics card manufacturers know that the TV is going to chop off the edges of the picture. To compensate, they make the picture a little smaller to ensure that you don't lose anything. Because they don't know how much the TV will overscan, they tend to overcompensate, leaving a black border.
This would be all well and good if for some crazy reason you were trying to word process on your TV and didn't want the menu bar to disappear off the top of the screen. However, if you're trying for the 'watching television' experience, the black bars all around the picture are rather irritating.
A partial solution
Fortunately, you should be able to enable overscan mode on your TV card. The procedure for this will vary according to your card - my ATI Radeon card has it as an undocumented feature in the Windows control panel - there's a utility called 'Rage3D Tweak' which (amongst other things) makes an 'enable overscan' toggle box appear.
Hooray! The nasty black borders disappear and once more all seems well.
However, you are left with the nagging feeling that something is still not right. Wait! Now that we're not compensating for the TV's overscan, doesn't that mean we're losing the edges of our picture?
Unless you have an extraordinarily well calibrated TV (or one that allows you to calibrate it yourself), you will in fact now be losing some of your painstakingly downloaded picture off the sides of the screen.
This seems a shame.
DIY black borders
What you need to do is introduce some black borders of your own. But not hastily estimated nasty black borders like the graphics card produced - no! These black borders will be carefully sized in order to exactly fill that part of the picture that the TV is scanning off the edge of the screen, ensuring that the whole picture is squeezed into the displayed area.
You might think that it would be a simple matter to resize your video window on the desktop such that it has some gaps around the edges and fills your TV screen precisely. If you find you can do this, then good for you - all is well. (Windows users - Note that an app called Zoom Player will enable you to configure precise black borders and save you having to resize the media player window each time.)
However, in the case of (at least) certain ATI cards, you can only enable overscan mode when the card is set to what ATI call 'theater mode', where the 'overlay' (i.e. the part of the screen that has your video clip playing on it) is automatically displayed full-screen on the TV. This scuppers any attempts to avoid the overscan because it insists on filling the TV screen with the video clip regardless of its size and position on the desktop.
A straightforward way to introduce one set of borders (in spite of 'theater mode') is to adjust the aspect ratio of the picture. Some media players (e.g. Zoom Player) will allow you to adjust this. If you make the picture wider, this effectively introduces horizontal borders at the top and bottom of the image sent to the TV. (Think about how a widescreen movie looks on a normal TV). If you adjust the picture width just right, you can get the top and bottom edges of the picture to exactly match the top and bottom of the TV screen.
So now you have compensated for the overscan at the top and bottom of the picture, but are still losing some of the picture off the edges.
Happily for Windows users, there exists a nifty utility called DivXG400. This can be made to introduce vertical bars at the side of the image in such a way that they become part of the overlay area, and thus appear on the TV. All you have to do is adjust the width of the bars until your picture exactly matches the displayed area.
So, now, relax and enjoy your DivX, safe in the knowledge that not one pixel can escape your attention.
At the time of writing -
Rage3D Tweak available at
Zoom Player available at http://www.inmatrix.com/files/zoomplayer_download.shtml
DivXG400 available at http://www.tac.ee/~prr/videoutils/divxg400.html