Cannot adjust Overscan on Pi>HDMI>Polaroid LCD
#1
Hi All -1st Post here! Big Grin

I was having real trouble getting any sound at all out of my new Pi with Raspian, so sorta last resort I flashed another SD card with OPENELEC and wham! TUNES! no need to send it back! etc! Nod

There is one problem tho; the Polaroid TV itself boots up proclaiming it's 1440 x 900, 60 Hz but there is some serious overscan coming from the Pi- the crawling info at the bottom, buttons in the right corner, and logos at the top are mostly off screen.

The OPENELEC resolution was set default at 1440 x 900; changing it to any other value just makes the overscan worse.

OPENELEC is the current version: 5.0.8

To make things totally confusing, Noobs Raspian on the same SD card boots up with a bit of underscan - 3/8" black bars surrounding the display (on a 10"x16" LCD).

So what should I try next? Thanks in advance guys.
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#2
Look for the setting on your tv to turn overscan off.
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#3
(2015-04-03, 00:15)CaptSunset Wrote: There is one problem tho; the Polaroid TV itself boots up proclaiming it's 1440 x 900, 60 Hz but there is some serious overscan coming from the Pi- the crawling info at the bottom, buttons in the right corner, and logos at the top are mostly off screen.

For info - the Pi isn't adding Overscan, Overscan is what your TV does.

Most CRT (aka tubed) TVs overscanned by default, on purpose, so you didn't see the edges of the pictures (which often contained a little bit of junk that broadcasters didn't really want you to see). Flat panel LCDs and Plasmas usually default to having some overscan too for similar reasons. On many (most?) displays this can be disabled, at least when driving the panel at native resolution, but this isn't possible on all displays. (On my first gen Sony 1920x1080 HDTV I can only get no overscan when feeding it 1080i or 1080p, there is always a small amount in 720p or SD modes. I have an LG display that is 1680x1050 which will only disable overscan when driven 1680x1050, but will only do this at 60Hz, so I have to have overscan when watching 50Hz content...)

The first thing, as others have suggested, is to look in all the menus to see if your HDTV has an option to disable overscan. This can be called lots of different things - and in some cases is triggered by relabelled the AV input as "PC". It may be called PC Mode, Just Scan, True Format etc.

If you can't disable your display overscan then you need the Pi to compensate. You can try this in two ways.
1. Set the overscan settings in the config.txt file on your Pi. This will get the Pi firmware (I think) to handle overscan compensation.
2. Calibrate in Kodi. This will get Kodi to scale any video and GUI to compensate for your display overscan.
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#4
Thanks guys; it is hard to keep my logic straight sometimes.Tongue

This Polaroid LCD is early, from 2007.

It has P. Mode (Vivid, CInema, etc) and P. Size, which says 'Not Adjustable' -I'm assuming that's the one that would have handled the overscan?

It also has Input of TV, Video1 (AV), V2 (S-Vid), V3 (YPbPr) , & V4 (HDMI)

What puzzles me is that booting Noobs Wheezy results in a quite acceptable amount of underscan; but booting into OpenElec results in serious overscan that can't seem to be reduced by changing screen resolutions within Kodi.

I guess that leaves config.txt, but also me with other questions- is there a separate config.txt file for each boot choice?
Otherwise, why the difference in output?
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#5
P Size is probably there to allow you to adjust how 4:3 content is displayed on a 16:9 screen. Overscan is usually elsewhere - often not a "Picture" control but more of a set-up (sometimes on an input-by-input basis) setting. It is one of those settings that you aren't expected to adjust that often - so unlike volume, contrast, brightness etc. it can be trickier to find. Not every TV will have the control though.

I only run OE as a standalone install on its own SD card and don't run NOOBs so can't comment on that.
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#6
(2015-04-03, 15:14)CaptSunset Wrote: I guess that leaves config.txt, but also me with other questions- is there a separate config.txt file for each boot choice?
Otherwise, why the difference in output?

Paste you config.txt on pastebin.com.

It's possible your config.txt may include some inappropriate overscan settings. These settings may be producing an acceptable image for Wheezy (which would otherwise have a huge underscan border) while also making OpenELEC overscan significantly.

As noggin suggests, the solution is to configure your TV so that it's using "Full size" or "1:1 Pixel" or whatever the unscaled video setting is. Once you have that configured, you should be able to adjust any overscan settings in config.txt so that all distributions display correctly.
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.
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#7
Thanks much Noggin & Milhouse; I'm trapped into a couple days of holiday-ing, but will get on this asap.

pastebin, huh? musta missed the memo; it's added to my bookmarks, so much to learn...

btw, I posted an enthusiastic mention on the screenwriters forum American Zoetrope- (they like 'works right straight from the download')
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#8
OK, here's the NOOBS config.txt file on pastebin (public I hope) : http://pastebin.com/nB91nZma

Overscan & Console Size are both mentioned; but I was under the impression that OpenELEC was standalone software, so would it be somehow using the Raspian settings? (The small amount of underscan running Wheezy is no problem)

There may be some interaction at the dual-boot loader? dunno

I reflashed the SD card as my only way to review the whole problem, NOOBS detected the HDMI monitor at 1392x868, 60 Hz.
OpenELEC went with 1440x900; and is running Kodi 14.1
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#9
I've never used NOOBS but as far as I'm aware those config.txt settings will apply to every OS you boot.

My advice would be to remove the "NOOBS Auto-generated Settings" from the end of that file, in particular the overscan_* settings, and then disable overscan by setting disable_overscan=1.
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.
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#10
Thanks Milhouse! sorry that my time isn't my own lately...
OK I will try that.

NOOBS is a 1st boot utility AFAIK; on the Pi 2B is will install Raspian (Debian flavor) from the SD card and other OSs as multiboot options direct from the net. I have just Raspian & OpenELEC (Kodi) installed.
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Cannot adjust Overscan on Pi>HDMI>Polaroid LCD1