What are the best settings for composite, to get the right aspect ratio and maximize screen use?

[Oen]

Hello everyone!

I'll start off with stating I have used, and think I understand, the following commands:

• disable_overscan
• overscan_scale
• overscan_top, bottom, right and left

I'm outputting to a standard definition television, using RCA cables.

The issue I am running into is that I can't figure out if I should be changing settings in the config.txt or within RetroArch to get the right aspect ratio and have everything fit correctly.

Three easy issues to replicate.

1. If I use overscan_top, overscan_bottom etc... to crop the screen to what is visible, the issue is everything appears letter box, there are black bars at the top and bottom. The games appear to have the right aspect ratio, but SNES games only fill 4:3 square (8:7 really..) within that letter box area. It would prefer it fit to the top and bottom of the screen.

2. If I use overscan_scale, this seems to make 720x480 fill into 640x480. This doesn't really work as it really seems to skew the aspect ratio of everything. GBA has a 3:2 aspect ratio, which happens to be the same as the NSTC SDTV resolution of 720x480. When overscan_scale is on, that makes the 3:2 view fill the 4:3 screen. Everything is stretched vertically, which prevents the letterbox effect. Though besides the skew, it makes SNES games appear as a noticeably slim picture in the middle of the screen.

3. If I don't crop the overscan, SNES games appear very close to correct. They fill the 4:3 screen. When I play GBA games though, they assume all 720 pixels wide are visible (they're not of course), so the left and right side of the screen are missing.

So my question is... what exactly is the best practice to resolve this? I would prefer SNES/NES like games are full screen (or close to it, I know they're 8:7). Then have games like GBA letterboxed. As I said above, GBA games look fine when I don't used overscan_scale, but SNES games appear much smaller, as a little 4:3 picture within a letter box view on the screen.

When I boot any emulator, and Push A to get into setup, it does state the video is SDTV NTSC 4:3. The tvservice command returns the same information as well.

Any advice is appreciated. Thanks!

[justinbeaird]

I am interested in this also just waiting for my new pi. so if you find the best setup for old tv please share.

[Oen]

@justinbeaird A side note, if you use Kodi or RasPlex, they both have a very easy setups for video calibration. You move the a marker in the top left and bottom right until it fits your screen. Then they show you a square, and you stretch and expand it to make it a perfect square. These two methods allow them to maximize your screen space and have the proper aspect ratio for videos.

As I mentioned above, you shouldn't have any issue getting everything on the screen. It just doesn't look right. The black bars at the top and bottom aren't the end of the world, but are noticeable when the 4:3 games have a black border visible on all sides of the image.

Here is an image so you know what to expect.

The black box and green box are both 4:3. The red box represents the 3:2 (720x480) signal being sent. Which the GBA emulator assumes is completely visible.

The black and green boxes are the typical 4:3 area on a CRT TV, and again the red area is the 720x480 signal. From my understanding most TVs work like the green box shown above. The signal is a little wider, so you lose a little on the sides, but there isn't any critical information.

The problem is, that red box is the area Gameboy Advance uses, so you lose view of lives and health meters that are in the corners of most games. My setup last night was like the black box shown, where the red box fits entirely within it, and appears like a letter box. You can see there are small gaps at the top and bottom. When a SNES game played in the middle, it isn't 4:3, but really 8:7, so it's slimmer than the green box shown in the middle. You can see though, the green box has a gap on all sides within that black box. So imagine a square image within the green box, but the black box representing your view area. That is what you'll experience unfortunately. It's what I'm hoping to resolve.

Personally I think the GBA emulator should shrink the red box to be within the green box, when a GBA game is launched, otherwise leave the display as the green box so that 4:3 games fill the screen top to bottom. :)