I currently have two Retropie setups: one on a Raspberry Pi 3b and the other on a Raspberry Pi 4b. I did this to work through some issues I was having getting the OS updated from the Raspbian Stretch to Buster. Now that I have two working units, I brought one to the bavastudio to try and see how it looks attached to a 27″ CRT TV. Using a handy HDMI to RCA convertor I can take the signal from the Retropie and convert it to an AV signal that plugs right into an old school CRT TV’s RCA inputs. So, that’s easy enough.
After that, I needed to adjust the overscanning option on the Retropie to make sure it scales appropriately to the TV. To do this you take the SD card out of the Retropie and plug it into your computer and edit the config.txt file on that boot disk. The existing settings for overscanning were the following for me:
# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1
# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
overscan_left=16
overscan_right=16
overscan_top=32
overscan_bottom=64
I uncommented the disable_overscan option and set it to 0 and then commented out the rest:
# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=0
# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=32
#overscan_bottom=64
I also tried to change some settings in the Retroarch config via the Retropie interface, but I’m not certain those changes made a difference. The above does get me consistently 4:3 Atari games on a 27″ TV with very little black space around the margins. It maps almost 1:1 against the actual Atari 2600 and 5200 consoles I have running on that TV—so I have a control to test with.
Next step will be trying this out on the Retropie 4b, but I do like that at least one of the Retropies is using a CRT rather than a 4K monitor—the latter just seems wrong for all kinds of reasons.
Any reason you’re not using the built in composite out from the Pis?
Hi Ryan,
I did try it on the Retropie 3b a while back and it wasn’t working for me, so I abandoned that approach (along with bluetooth wireless controllers). That said, it would be easier, so I need to return to that. I have a mini to composite around somewhere, so I will give that a go again on the 3b and test it on the 4B. The wireless controllers would be the real coup, so thanks for giving me the nudge.
As an update here, I did try the composite out on both the 3b and 4b Pies with no luck. The 3.5 mm mini jack to RCA I have must not be working correctly—which I am seeing is a common issue. I ordered a new one from Adafruit based on some recommendations in the forums, this will help confirm if the cable was the issue (I am thinking it might be).
Given what a PITA over scanning is proving on my Retropies, I’m hoping the jack out works and saves me from trying to play around with the overscanning settings in the config.txt file. I tried the same settings I listed above on my Raspberry Pi 4b, and nothing I did could get rid of 1.5″ black margins on the left and right of screen.
When I got the Adafruit mini composite to RCA the output on the Raspberry Pi 3B and 4B worked (https://www.adafruit.com/product/2881), so the issue was the mini 3.5 composite I was using for sure. Also, the output works on both my 19″ PAL TV and 27″ NTSC, but there are a series of settings I had to work through, namely overscan as referenced above in this post. That said, I’m finding those settings vary widely, so there is no one size fits all there, so this post may be a bit useless in the end.
Alternatively, while you will have to change several settings in config.txt for the mini to Ccmposite to work, the following Retro CRT TV Out configurations automate some of the ratio switches for various consoles and arcade gammes, which makes this process a lot easier: https://github.com/Sakitoshi/retropie-crt-tvout
Below is a look at the config.txt changes for an NTSC TV the Retro CRT TV Out configurations method suggests, and I found they work quite well for both NTSC and PAL:
## Copy the following lines to the end of your /boot/config.txt file
#
# CRT tweaks
sdtv_mode=0 #Enables NTSC 480i mode. EmulationStation will switch to 240p mode when Retroarch launches.
sdtv_aspect=1 #4:3 aspect ratio.
disable_overscan=1 #We'll handle overscan on a per-system basis with Retroarch.
audio_pwm_mode=2 #Optional but recommended. Enables an alternative audio driver that works great with the analog audio out.
#framebuffer_width=580 #To properly use this setting you first need to edit out "-yres 448" on "configs/all/runcommand-onstart.sh" and "-yres 480" on "configs/all/runcommand-onend.sh". Optional but recommended if you'll only use a crt tv. Adjust the text of the RetroPie config menus.
#framebuffer_height=360 #To properly use this setting you first need to edit out "-yres 448" on "configs/all/runcommand-onstart.sh" and "-yres 480" on "configs/all/runcommand-onend.sh". Optional but recommended if you'll only use a crt tv. Adjust the text of the RetroPie config menus.
#hdmi_group=1 #Optional. Forces HDMI into 480p mode, useful if you want to emulate a crt tv to test something on an HD display.
#hdmi_mode=2 #Optional. Forces HDMI into 480p mode, useful if you want to emulate a crt tv to test something on an HD display.
#hdmi_ignore_hotplug=1 #Optional. Forces composite tv-out even if HDMI is connected.
The other piece (I’m now officially using these comments as notes to return to for a post) is the retroarch config settings for video rtio seem to work best on the 27″ CRT at 16:9 and if I recall correctly are better at 4:3 for the 19″ PAL TV, but need to check all that and document. Getting good composite out of for the Retropie (and the Batocera I am learning) is a royal pain in the ass. You are better off just pushing HDMI out to a HDMI -> AV convertor given that seems to do most of the heavy lifting for you.