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neoRiley
Level 7

42 x 22 margin around screen area?

I've tried to search the docs and forum but nothing is posted about this non-viewable area around the screen when you set something to 0,0 position.

When I create an object and position it at 0,0, 42 pixels on the left and 22 pixels at the top are off screen. If I set the translation = [42,22] it's perfectly aligned with the left/top edges of my tv 

1.  Is this something that's expected / anticipated / done on purpose?
2. If so, what are the reasons behind it?  would love a link to docs explaining it further
3.  Is it different on other TV's?
4.  Is it different for different resolutions/aspect ratios?

Thanks for the help
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8 Replies
Roku Employee
Roku Employee

Re: 42 x 22 margin around screen area?

"neoRiley" wrote:
I've tried to search the docs and forum but nothing is posted about this non-viewable area around the screen when you set something to 0,0 position.

When I create an object and position it at 0,0, 42 pixels on the left and 22 pixels at the top are off screen. If I set the translation = [42,22] it's perfectly aligned with the left/top edges of my tv 


It sounds like your TV may not be displaying the full resolution, or may be in overscan mode.
It's a bit outdated, but you may want to read https://sdkdocs.roku.com/display/sdkdoc ... 2Safezones
Also, if you search the web for "tv action safe area" or "tv title safe area" you may find more general information.
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Komag
Level 9

Re: 42 x 22 margin around screen area?

Sounds like the overscan demon strikes again. Someday we'll kill it for good.
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EnTerr
Level 8

Re: 42 x 22 margin around screen area?

@neoRiley -
look here for typical amounts https://en.wikipedia.org/wiki/Overscan#Overscan_amounts
In your case we see 2-3% (depending if you are in 720 or 1080).

My rule of thumb is, I assume that 3-5% on each side are LIKELY to be lost due to overscan and plan accordingly. Meaning, don't put stuff you care about there - but keep in mind on some TVs those edges will be visible so don't leave them contrastingly empty either
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EnTerr
Level 8

Re: 42 x 22 margin around screen area?

"Komag" wrote:
Sounds like the overscan demon strikes again. Someday we'll kill it for good.

Highly doubtful, i am afraid. There is absolutely no need these days for overscan but for historical reasons all TV sets ship in that mode and most people watch TV in that mode. For LCD/[OQ]LED screens that means they take the image (e.g. 1920x1080), enlarge it a little (say to 2004x1124), then chomp the presumed "underscan" edges (say 42 horizontally and 22 vertically) - and display the 1920x1080 leftover on the 1920x1080 discrete pixels of the LCD panel. Coincidently, that means one's line-art will be blurred by the +6% magnification - so don't you do line art for TV
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Komag
Level 9

Re: 42 x 22 margin around screen area?

Oh I'm aware of the history, I just believe it will eventually go away completely. Not soon of course, but at some future day.
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neoRiley
Level 7

Re: 42 x 22 margin around screen area?

"EnTerr" wrote:
@neoRiley -
look here for typical amounts https://en.wikipedia.org/wiki/Overscan#Overscan_amounts
In your case we see 2-3% (depending if you are in 720 or 1080).

My rule of thumb is, I assume that 3-5% on each side are LIKELY to be lost due to overscan and plan accordingly. Meaning, don't put stuff you care about there - but keep in mind on some TVs those edges will be visible so don't leave them contrastingly empty either

Thanks VERY much for the reply AND information - I really appreciate it
So, are you saying that on every project you do, you account for 3-5% area around a given project's design for content?
I'm going to ask this next question, though I realize you probably would have pointed it out:  Is there a way to programmatically determine this safe area of what is actually viewable on any device?
Thanks again for your help,
John
PS> Of course this is my first venture into a Roku (TV) project, so any silver bullet-type tips/links are very much appreciated
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EnTerr
Level 8

Re: 42 x 22 margin around screen area?

Yes, you should be ready screen fringes maybe get be chewed away on screen. There is no way to know if that's happening, so don't put important stuff there. This btw is the case developing for tv on any platform
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neoRiley
Level 7

Re: 42 x 22 margin around screen area?

"EnTerr" wrote:
Yes, you should be ready screen fringes maybe get be chewed away on screen. There is no way to know if that's happening, so don't put important stuff there. This btw is the case developing for tv on any platform

Ok great, thanks again for the information and help, I do appreciate it,
John
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